CONGENITAL ABNORMALITIES AND CONDITIONS
OF THE PANCREAS PRESENTING IN ADULTS AND CHILDREN
Introduction
Congenital abnormalities and conditions of the pancreas may be encountered in adulthood as well as in childhood, on a variety of imaging studies (1-3). These
conditions may be significant or asymptomatic. Multiple uncommon and rare conditions which may affect the pancreas related to developmental variants and
inherited disorders include pancreatic divisum, annular pancreas, absent dorsal pancreas the latter with or without a heterotaxy syndrome - and other variants of
pancreatic development; intrapancreatic splenule; cystic fibrosis, congenital cysts, von Hippel Lindau disease, and lymphoepithelial cyst; and very rare conditions
including Schwachman-Diamond syndrome, nesidioblastosis, and pancreaticoblastoma. Since some of these conditions and developmental variants are
asymptomatic or discovered in young adulthood or adult life on cross-sectional imaging studies performed for unrelated reasons, they may come to medical
attention in adulthood. Other conditions are discovered early in life, and others such as annular pancreas have varying presentations and may be discovered in
childhood or adulthood. Adult and pediatric radiologists who perform gastrointestinal imaging should therefore be familiar with this spectrum of variants,
conditions, and disorders, and their potential complications, as illustrated in this poster. The utility of various modalities for correct prospective diagnosis will also
be stressed, with emphasis on CT.
1,2
1,2
Intrapancreatic Splenule
Intrapancreatic accessory spleen (or splenule) is much more common than realized, although there are few reports of its identification on imaging (37-39). In general,
accessory spleens, which vary in size from a few millimeters to several centimeters, are found in up to 30% of autopsies, and almost 20% are in or near the pancreatic tail
(37). Accessory spleens, in individuals who have not had previous splenectomy or trauma, can be found anywhere within the embryologic dorsal mesentery of the stomach
and pancreas, and rarely have even been reported in the pelvis or scrotum (37). They should be considered a congenital variant, whose significance is only that they need to
be distinguished from other lesions which are clinically important (37-39). At CT (Fig. 15) and MR, an intrapancreatic splenule has a characteristic location and appearance;
a well-defined round uniform density lesion in the pancreatic tail is seen, which has the same density/intensity as the spleen on non-enhanced and contrast-enhanced
examinations. If the diagnosis remains unclear, an intrapancreatic splenule can be confirmed on SPECT sulfur colloid or head-damaged red blood cell scans (37-39).
1,2
Joseph P. Mazzie, D.O. , Lewis Shin, M.D. , Anita P. Price, M.D.
2
1,2
1,2
Thomas H. Smith, M.D. , Burton M. Gold, M.D. , Douglas S. Katz, M.D.
Departments of Radiology, Winthrop-University Hospital1, Mineola, NY
State University of New York at Stony Brook2, Stony Brook, NY
Cystic Fibrosis
Pancreatic Divisum
Pancreatic divisum is the most commonly encountered congenital ductal anomaly of the pancreas, and is present in up to 6-10% of the population (4). During
development, dorsal and ventral pancreatic buds are formed; in the second month, the ventral bud elongates, rotating behind the duodenum into the position of the
pancreatic head and uncinate process, placing it more caudal than the stationary dorsal bud, the latter which gives rise to the pancreatic body (5,6). Fusion of the
dorsal and ventral ducts then usually occurs, resulting in the main pancreatic duct, the duct of Wirsung (Fig. 1A). Lack of fusion results in divisum, with persistence
of ventral and dorsal pancreatic ductal systems. The ventral portion of the pancreas arises near the common bile duct, and drains into the duodenum at the
ampulla of Vater (major papilla) via the duct of Wirsung; a dorsal pancreas which empties into the duodenum at the minor papilla via a separate duct of Santorini is
also present (5). On ERCP, in the complete form of divisum, a shortened duct with early arborization is demonstrated on cannulation of the major papilla and
injection of contrast into the ventral duct. Cannulation of the minor papilla and injection of contrast into the dorsal duct reveals a separate duct (Fig. 2).
The relationship between pancreatic divisum and pancreatitis is controversial (7-10). In patients with acute pancreatitis and no definitive explanation, there is a
reported high prevalence of divisum, in up to 12-50% of cases (7). The cause of the pancreatitis is believed to be inadequate drainage through the minor papilla.
As CT is used routinely to follow and detect complications of pancreatitis, the recognition of divisum could point to the potential etiology of the pancreatitis (Fig.
3). A variety of findings have been reported which suggest the presence of divisum. A distinct oblique cleft between the ventral and dorsal pancreas has been
reported (6). Also, 44% of patients have been reported to have lobulation of the pancreatic head; however, this may also occur in patients without divisum (5).
Enlargement of the pancreatic head has also been reported in divisum, and in the absence of heterogeneity or other signs of pathology such as biliary or pancreatic
ductal obstruction, the diagnosis may also be suggested (4). Additionally, the characterization of pancreatic ductal anatomy on CT in divisum is subtle, even with
thin-sections, and establishing the diagnosis of divisum requires that both the dorsal and ventral ducts be identified (6,10). In one study, the dorsal duct was
visualized in all 12 patients as a result of the duct's predominantly horizontal course, but the ventral duct was seen in only 5 of the patients, likely due to its partially
vertical course (6). Zeman et al. (6) therefore proposed that the criteria for diagnosing pancreatic divisum on CT include the failure to see a union of the dorsal and
ventral ducts and identification of the ventral duct joining the common bile duct. To our knowledge, the use of multidetector CT to identify pancreas divisum has not
yet been reported.
On MRCP, divisum is diagnosed by identifying the dorsal duct passing anterior and superior to the common bile duct on axial images (11).
Annular Pancreas
Annular pancreas is the second most common congenital abnormality of the pancreatic ductal system after divisum (12). The exact etiology is unknown, but one
theory is that adherence of the tip of the right ventral pancreas to the duodenal wall results in a ring of tissue around the duodenum at the time of dorsal rotation (12)
(Fig 1B). Another theory is that the anomaly results from abnormal rotation and migration of the ventral bud that results in the ring of tissue (12). One classification
system for annular pancreas proposes three types: a divisional annual pancreas, where the ventral and dorsal duct systems fail to fuse; branch annular pancreas,
where the tail of the annular duct arises as a branch from the main duct; and main duct annular pancreas, where the tail of the annular duct fuses with the dorsal duct
to form the main duct (13).
The second portion of the duodenum is encircled in 85% of cases, and the first or third portions are encircled in the remaining 15% (12). The ring of pancreatic
tissue may be complete or incomplete. Associated anomalies occur in 75% of patients, including Down's syndrome, tracheoesophageal fistula/esophageal
atresia, imperforate anus, and Hirschsprung's disease (12). Approximately half of all patients present in childhood with duodenal obstruction (7), and males are
more commonly affected than females (13). When diagnosed in older children or adults, a less symptomatic or even asymptomatic presentation occurs, usually
without other congenital anomalies. Symptoms can include nausea, vomiting, upper abdominal pain, and less commonly jaundice and GI bleeding (7). There are
increased rates of acute and chronic pancreatitis, which is usually limited to the pancreatic annulus (7). There have also been reported cases of annular pancreas
and divisum occurring in the same patient, which is not surprising as the migration of the ventral pancreas and the fusion of the ductal systems occur during similar
times of intrauterine life (13).
Several imaging modalities have been used to detect annular pancreas (Figs. 4-6), including plain films (“double bubble” sign), contrast radiography, CT, MR,
and ERCP (12). On UGI, an eccentric defect on the outer margin of the second portion of the duodenum suggest the diagnosis, with mucosal effacement in the
absence of mucosal destruction and symmetrical dilatation of the proximal duodenum with reverse peristalsis (13). On contrast-enhanced CT, pancreatic tissue
can be differentiated readily from the duodenum, which contains variable amounts of gas, fluid, or oral contrast (12, 14-15). Additionally, contrast-enhanced CT
can be used to distinguish between a partial or complete ring of tissue encircling the duodenum and the apparent circumferential thickening of the duodenal wall
which may be associated with duodenal stenosis (12). The diagnosis of annular pancreas on ERCP is also quite specific; two major patterns are seen: fusion of the
two ductal systems (85%), and the less common annular divisum variant (12,16,17).
Fig. 5. A. Newborn boy with “double bubble” sign
on frontal chest and abdominal radiograph, due to
duodenal atresia and annular pancreas. B. Image
from an upper GI series in a newborn girl with
duodenal stenosis and annular pancreas shows
significant narrowing of the second portion of the
duodenum; the distal duodenum also does not
distend well.
Fig. 17. Newborn boy with congenital pancreatic head and neck cyst. A. Ultrasound demonstrates a 4.1 by 2.5 cm simple cyst adjacent to the liver.
Cyst was detected on prenatal sonography (not shown). B-C. CT on the same patient shows a large cyst in the expected location of the pancreatic
head. There is associated biliary and pancreatic ductal dilatation.
Congenital Cysts
Fig. 12. 33-year-old woman with chronic pancreatitis and non-incidental absence of the dorsal pancreas.
Notice subtle calcifications in the pancreatic head and neck immediately adjacent to the portal-splenic
venous confluence (A). There is no pancreas anterior to the splenic vein (B).
Fig 18. Cystosis of the pancreas in an older woman, of uncertain etiology. Note the absence of any renal
cysts. There is some sparing of the pancreatic head and neck region (A). Appearance simulates cystosis
which can be rarely seen in patients with cystic fibrosis.
Fig. 6. 35-year-old man with nausea. CT scan shows an annular pancreas. Note gas in the duodenal lumen which is completely encircled by the pancreatic
head. The distal pancreas is also shortened (A). Note the prominent hemiazygos to the left of the aorta (A-C), in this patient with multiple congenital anomalies,
including dextrocardia (not shown). (Courtesy Dr. Hines and Dr. Michael Macari, Bellevue Hospital and New York University Department of Radiology, New York,
New York.)
Absent Dorsal Pancreas and the Heterotaxy Syndromes
As noted above, normally during development, the ventral pancreatic bud forms the pancreatic head and uncinate, and the ventral bud migrates around the
duodenum where it fuses with the dorsal pancreatic bud (21-22). Failure of development of a normal dorsal bud results in congenital absence of a majority of the
pancreas, whereas agenesis of the ventral bud or of both buds is not compatible with life (23). Absence of the dorsal pancreas (ADP) is relatively rare and is
typically diagnosed incidentally during an investigation of a patient with abdominal pain. The first reported case in a living person in the English literature was in a
26-year-old diabetic man presenting with duodenal ileus (24). An association with diabetes has been noted in other patients (24, 25), as well as with the
polysplenia syndrome, as noted below.
The diagnosis of ADP can be suggested or established on sonography, CT (Figs. 11-12), or MR, when there is absence of pancreatic tissue ventral to the splenic
vein (26-28). ADP can be misinterpreted as pathology, especially on sonography. Deignan et al. (27) suggested that this diagnosis should be considered when a
vertical echogenic line, which separates the normal pancreatic head and the adjacent ill-defined retroperitoneal fat, is found.
The finding of premature termination of the pancreatic duct on cannulation of the minor papilla is suggestive of ADP (29), but findings on CT or MR are
diagnostic, with absence of pancreatic tissue ventral to the splenic vein (26,28). MRCP has also been used in lieu of ERCP in this situation (28).
Complete fatty replacement of portions of the pancreas are unusual, although lesser degrees are common (30). Proposed etiologies for diffuse or focal fatty
replacement in adults include obesity, aging, diabetes, chronic pancreatitis, pancreatic ductal obstruction, and steroid therapy (30). In contradistinction to ADP,
fatty replacement of the dorsal pancreas should retain the endocrine apparatus along with ductal and vascular structures. On CT, a linear density (the pancreatic
duct) can be identified in the low attenuating, fat-replaced pancreatic bed region (30). Uneven fatty replacement has been characterized using CT by Matsumoto et
al. (31), in a study of 80 patients. The most severely affected area of fat replacement was the anterior aspect of the head of the pancreas. The posterior aspect of
the head, the uncinate process, and the tissue adjacent to the common bile duct were the most resistant to fatty replacement (31).
Heterotaxy, or situs ambiguous, is a disordered arrangement of organs in the thorax and abdomen. In contrast to situs inversus, where a mirror image
arrangement of abdominal and thoracic organs occurs (Fig. 13), in one form of heterotaxy - the polysplenia syndrome (also known as double left-sidedness) bilateral bilobed lungs, a centrally located liver, a stomach in indeterminate position, and multiple spleens are discovered. Interruption of the inferior vena cava with
azygos or hemiazygos continuation in conjunction with cardiac anomalies occurs (32).
There is a paucity of literature describing the radiologic appearance of the pancreas in patients with polysplenia (Fig. 14). Pathologic examination of six
pediatric patients in a series by Hatayama et al. (33) showed a short, “stubby” pancreas. Since then, few cases have appeared in the imaging literature (32, 34-36).
The presence of only a pancreatic head was observed in 5 of 8 patients reported by Fulcher et al. (36), with one other patient having a pancreatic head and a small
pancreatic body. One patient in this study, with asplenia, was also described as having a short pancreas. There have been multiple theories as to why the
pancreas is short in heterotaxy syndromes, but the most accepted explanation is that ADP occurred.
von Hippel Lindau disease (VHL) is an autosomal dominant disorder characterized by central nervous system hemangioblastomas, retinal angiomatosis, renal cell
carcinomas, pheochromocytomas, and cyst formation in the kidneys, pancreas, and epididymis. Only a few percentage of patients develop all of these manifestations, and
approximately 50% have only single-organ pathology (Fig. 19) (53). Pancreatic lesions include cysts, cystic replacement, cystic tumors, and islet cell tumors. In a review by
Hough et al. (54) of 52 patients, 56% had a pancreatic abnormality. Pancreatic cysts were identified in 21 patients, and ranged from a solitary cyst to multiple clusters of cysts
to cystic replacement of the pancreas. In six patients, the pancreas was the only site of intra-abdominal findings; four patients had cysts, and two had islet cell carcinomas.
Two patients with pancreatic cysts as the initial sole manifestation of VHL, years later developed extraabdominal findings, emphasizing the significance of pancreatic
imaging in VHL (54). Similarly, Girelli et al. (53) observed 5 patients with multiple pancreatic cysts with minimal or no symptoms who were subsequently diagnosed with VHL.
Therefore, VHL should be a diagnostic consideration in young patients with pancreatic cysts, especially those without specific pancreatic symptoms.
Microcystic adenomas are also seen in VHL, and should be suggested when there is focal enlargement of the pancreas, with multiple, radially aligned small cysts forming
a central, calcified scar; however, clinical distinction from cysts is not important, as both simple pancreatic cysts and pancreatic cystic lesions are conservatively managed
(55).
Islet cell tumors (Fig. 19E-G) may be the only pancreatic lesion identified in patients with VHL (54). These commonly exhibit intense enhancement on CT or MR.
Calcification may be present, and necrosis may be seen with large tumors (2,55). Intraoperative sonography (Fig. 19F) is useful for guiding local resection of small islet cell
tumors (55).
Fig. 13. Incidental situs inversus in a 51-year-old woman. The pancreas would be totally normal in
appearance if the image was inverted.
Fig. 7. ERCP in a 53-year-old man shows an inverted “Ushaped” pancreatic duct, representing a normal variant.
Lymphoepithelial Cyst
Lymphoepithelial cyst (LC) of the pancreas is a rare lesion lined by squamous epithelium which is surrounded by lymphoid tissue and which contains keratinous material,
similar to lymphoepithelial cysts in the parotid gland (56). They are similar to epidermal inclusion cysts, but are distinguished by the presence of prominent lymphoid tissue
and the absence of hair or teeth. Although reported in the pancreatic body and tail, primarily in men who are either asymptomatic or who complained of non-specific
abdominal symptoms, LCs are believed to be most likely related to a developmental anomaly. It is proposed that they develop from ectopic pancreatic tissue contained
within a peripancreatic lymph node, with subsequent fusion with the pancreas; alternatively, they may represent a branchial cleft remnant. The latter theory was proposed
because LCs resemble the histologic appearance of branchial cleft cysts, and the former theory was proposed because of the characteristic location of the LC along the
anterior surface of the pancreatic body or tail (56-58). Cyst formation may result from chronic irritation of ectopic pancreatic epithelium with subsequent squamous
metaplasia (58). On CT (Fig. 20), an LC usually appears as a well-marginated multiloculated cystic lesion with thin walls and wall calcification, ranging in overall size from 2
to 13 cm (56,58,59). The differential diagnosis includes micro- and macrocystic tumors as well as cystic teratoma (56,60).
Schwachman-Diamond Syndrome
Schwachman-Diamond syndrome is a rare autosomal recessive disorder, but it is the second most common cause of pancreatic insufficiency in children following cystic
fibrosis (61,62). Schwachman-Diamond syndrome is characterized by exocrine pancreatic deficiency, neutropenia with a deficiency in neutrophil chemotaxis, and
metaphyseal dysostosis (61). Affected children present with foul-smelling feces, growth retardation, and recurrent infections. The pancreatic acini are replaced by fatty
tissue, although the pancreatic ducts remain normal (61). There have been very few reports of the imaging findings in this disorder (61-64). On CT and sonography (Fig.
21), patients have atrophy and marked lipomatosis of the pancreas, and this fatty replacement occurs at an early age. Patients with Schwachman-Diamond syndrome are
also at risk for leukemia and pancytopenia (61).
Fig. 8. 43-year-old man who underwent CT for evaluation of bladder cancer. CT shows a transverse lie of the entire pancreas (A-C), which is an unusual variant
not described in the literature (to our knowledge).
Fig. 14. Spectrum of pancreatic abnormalities in polysplenia, on CT. A-C. 45-year-old woman with incidental polysplenia. Note the absence of a pancreatic tail. The inferior vena cava is normal. There is a nearly
horizontal liver (C). Patient underwent CT for staging of breast cancer. (Case courtesy Dr. Philip Beuchert, BAB Radiology Group, Long Island, New York.) D-E. 49-year-old woman; the pancreatic head is fattyinfiltrated, and there is no pancreatic tail or body. F-H. 61-year-old woman who underwent CT because of “extrinsic compression” on the duodenum at endoscopy. There is a prominent pancreatic head without a body
or tail (F-G). There is hemiazygos continuation of the inferior vena cava (G-H).
Nesidioblastosis
Fig. 19. Spectrum of abnormalities of the pancreas in von Hippel Lindau syndrome. A-B. Multiple cysts in the pancreas in a middle-aged woman. C-D. 47year-old woman with a cyst in the pancreatic tail (C), and a cyst and adjacent renal cell cancer in the left kidney (D). E-G. 44-year-old man with two adjacent
pancreatic head and neck islet cell tumors (E), which were also confirmed at intraoperative sonography (F); note the hemangioblastoma in the upper lumbar
spine on the sagittal reconstructed image (G). H-J. Middle-aged woman who had a right nephrectomy in the past for renal cell cancer; there are multiple
pancreatic cysts (H), as well as multiple cystic and solid masses in the remaining left kidney.
Pancreaticoblastoma, also known as pancreatoblastoma, is a rare primary pancreatic neoplasm which histologically resembles fetal pancreatic tissue at approximately 7
weeks of gestation (68). Affected children are usually between ages 1 and 8, although pancreaticoblastoma has been reported in infants (68). Clinical presentation is
variable, ranging from an asymptomatic mass to various gastrointestinal signs and symptoms. On cross-sectional imaging, a large heterogeneous mass is discovered,
whose organ of origin may not be apparent, and metastatic disease, especially to the liver, may be identified (68). Therapy is surgical, and the role of adjuvant therapy is
unknown. In children, primary pancreatic tumors other than pancreaticoblastoma are extremely rare, with case reports of cystadenoma, hemangioendothelioma, and
rhabdomyosarcoma (68).
Fig. 9. Variant pancreatic tail anatomy. In this patient, the pancreatic tail makes an abrupt 90 degree turn anteriorly (A-C).
Fig. 20. Lymphoepithelial cyst of the pancreatic body, in a 42-year-old woman. CT shows a complex lesion composed of multiple small cysts with wall
calcification.
Fig. 15. 83-year-old woman with a round lesion in the pancreatic tail, which is isodense to the spleen. This
lesion was unchanged from a prior CT obtained at an outside institution two years earlier (not shown). The
lesion is consistent with a pancreatic splenule.
Fig. 2. 59-year-old man with
history of recurrent episodes of
pancreatitis and pancreatic
divisum. ERCP shows completely
separate ventral (A) and dorsal
(B) pancreatic ductal systems.
Fig. 21. Two-month-old boy with diarrhea and steatorrhea secondary to Schwachman-Diamond syndrome. Sonography shows atrophy of
the pancreas, and the pancreas is increased in echogenicity (A). The pancreas is difficult to identify on unenhanced CT (B-C). (Case
courtesy Dr. Dan Barlev, Long Island Jewish Hospital, New Hyde Park, New York.)
Fig. 11. A-B. Incidental absence of the pancreatic
tail on CT. C-E. 37-year-old woman with incidental
absence of the pancreatic tail, and an atrophic/nondeveloped pancreatic body (D). F-G. 83-year-old
woman with absent dorsal pancreas.
Notice
absence of any pancreatic tissue anterior to the
splenic vein (G).
Fig. 4. ERCP demonstrates an annular pancreas.
Fig. 3. 40 year-old man with history of pancreatic divisum based on ERCP (not shown) and prior cholecystectomy, now with recurrent episode of pancreatitis. CT
images (A-C) demonstrate inflammatory changes in the peripancreatic fat. The diagnosis of divisum is not evident on these images.
Nesidioblastosis is a diffuse ductoendocrine proliferation of beta cells in the pancreas, which may be associated with severe infantile hypoglycemia (65,66). Clinically,
affected infants may be large for gestational age, and can present with seizures, lethargy, and hypotonia (67). Failure to treat may result in mental retardation, permanent
neurological sequelae, and even death. There are two histopathologic forms, which occur with equal frequency: diffuse and focal. Originally considered to be a sporadic
disease, more recently an autosomal recessive etiology has been discovered in some cases (66). The exact pathophysiology is unclear, and numerous etiologies have
been suggested, but it appears that the glucose-mediated regulation of insulin release is lost (67). To our knowledge, the imaging findings of this disorder have not been
reported with any modality, nor has the appearance of the residual pancreas following surgery. Although the choice of definitive therapy has been controversial, in the past
25 years, 95% pancreatectomy has become the mainstay (67). Typically, the sooner a near-total pancreatectomy is performed in these patients, the better the outcome for
the infant (65). Initially following surgery, infants experience hypoglycemia, with normoglycemia developing between 6 and 18 months later. Possible complications include
permanent diabetes, frank steatorrhea, and pancreatic endocrine failure (65).
Pancreaticoblastoma
Fig. 10. 86-year-old woman with incidental 90
degree angulation between the pancreatic neck and
body.
Fig. 1. A. Schematic showing normal stages in pancreatic development. The
ventral and dorsal pancreatic buds fuse; the main pancreatic duct is formed by the
junction of the distal part of the dorsal pancreatic duct and the entire ventral
pancreatic duct, as shown. B. Proposed embryologic basis for an annular
pancreas. (From Larsen WJ, Human Embryology.)
True solitary simple cysts of the pancreas are rarely congenital and on even rarer occasions may be multiple. They may be encountered in the fetus, infant, child, or adult
(49-51). These pancreatic cysts are thin-walled, filled with clear fluid, and are bordered by true epithelium (Fig. 17); they are most often discovered in the pancreatic body
and tail (49). A female predominance has been reported for congenital pancreatic cysts (50). Congenital cysts are thought to arise from abnormal segmentations of primitive
ducts of the pancreas (49). Prenatally-diagnosed cases have been incidental or have been associated with polyhydramnios, and postnatal presentations have ranged from
asymptomatic to abdominal distension, vomiting from mass effect on the stomach, and jaundice from biliary obstruction (50). Treatment is total excision of the cyst when
located in the pancreatic body or tail, with internal drainage an option for lesions located in the pancreatic head (50).
Pancreatic cysts can also occur in patients with polycystic kidney disease as well as von Hippel-Lindau disease, but the pancreatic cysts which are found with increasing
frequency in older individuals on cross-sectional imaging studies performed for other reasons are acquired, analogous to most renal cysts in middle-aged and older people
(52). Pancreatic cysts in older adults are usually small and solitary, although occasionally they can be multiple (Fig. 18) (52). Pancreatic cysts in older individuals are usually
asymptomatic, in contrast to children with congenital cysts.
von Hippel Lindau Disease
Other Pancreatic Variants
A variety of other variants of pancreatic morphology exist, which have no known clinical significance (Figs. 7-10). Examples of a U-shaped pancreatic duct (Fig. 7),
an extremely unusual transverse lie of the entire pancreas (Fig. 8), a 90-degree anterior angulation of the pancreatic tail relative to the body (Fig. 9), and a
pronounced angulation between the pancreatic neck and body (Fig. 10) are illustrated.
Considerable variation occurs in the size, shape, and location of the normal pancreas (18-20). The lateral contour of the pancreatic head and neck, relative to
the gastroduodenal artery or anterior superior pancreaticoduodenal artery, is commonly variant. In a series of 119 patients who underwent thin-section CT, 35%
had an anterior, horizontal, or posterior lie of the lateral contour relative to the artery (18). Similarly, the pancreatic tail has a variable location relative to the left
kidney and spleen (19). The pancreatic tail can lie at the same level as the upper pole of the left kidney, but can also be cranial to as well as anterior or anterolateral
to the kidney (19). Cranial curving of the pancreatic tail is found in less than 50% of normal individuals, and close proximity of the splenic vein and pancreatic tail is
found in only 40% (19). Care must be taken so at to not mistake variant anatomy for a mass. With state-of-the-art multidetector helical CT, the finer details of
pancreatic anatomy can be appreciated.
Cystic fibrosis (CF) is an autosomal recessive disorder where a primary dysfunction of a chloride ion transporter results in pancreatic abnormalities including fatty
replacement, fibrosis, calcification, and cyst formation. Plain films may reveal pancreatic calcifications, which range from a few pinpoint calcifications to diffuse, granular and
fleck-like calcifications (40-43). There is no direct correlation between endocrine dysfunction in CF and the severity of pancreatic calcifications (42). Early in the disease, the
pancreas is diffusely heterogeneous with fat attenuation interspersed with soft-tissue attenuation. Complete fatty replacement usually occurs in older patients (Fig. 16)
(40,41). Soyer et al. (43) demonstrated a correlation of increased fatty replacement with smaller amounts of residual pancreatic glandular tissue, with the extent of
pancreatic exocrine insufficiency. This also correlated with a sonographic study by Willi et al. (44), where the pancreas in CF patients was smaller and more echogenic than
normal.
Typical cysts in the pancreas in CF patients are microscopic to small (1-3 mm). Larger cysts are less common, but rarely there can be complete replacement of the
pancreas with macroscopic cysts of varying sizes, called pancreatic cystosis (Fig. 18). The etiology of cyst formation is proposed to be related to the protein
hyperconcentration, inspissated secretions, and subsequent ductal ectasia (45).
The spectrum of pancreatic abnormalities in CF can also be demonstrated by MR, and reflects the varying degrees of fatty infiltration and fibrosis (46,47). Increased
signal intensity is observed on T1-weighted images, with fatty replacement, and areas of low signal on T1- and T2-weighted images may be seen, representing fibrosis (40).
The pancreatic duct, if demonstrated on MRCP, reveals varying degrees of stricture, dilatation, and beading (48).
Fig. 16. CT spectrum of pancreatic abnormalities in children and adults with cystic fibrosis. A. 45-year-old man with fatty infiltration of the pancreas, and
cirrhosis and splenomegaly. B-C. 16-year-old girl with cirrhosis, portal hypertension, and marked splenomegaly. There is marked fatty replacement of the
pancreas. D-F. 32-year-old man with marked fatty replacement of the pancreas. The pancreatic parenchyma is not recognizable (D-E). Note bronchiectasis
at the right lung base (F). G. 11-year-old boy with cystic fibrosis. Note the punctate calcification in the pancreas.
References
1. Herman TE, Siegel MJ. CT of the pancreas in children. AJR 1991; 157: 375-379.
2. Vaughn DD, Jabra AA, Fishman EK. Pancreatic disease in children and young adults: evaluation with
CT. RadioGraphics 1998; 18: 1171-1187.
3. Berrocal T, Prieto C, Pastor I, Gutierrez J, Al-Assir I. Sonography of pancreatic disease in infants and
children. RadioGraphics 1995; 15: 301-313.
4. Soulen MC, Zerhouni EA, Fishman EK, Gayler BW, Milligan F, Siegelman SS. Enlargement of the
pancreatic head in patients with pancreas divisum. Clin Imaging 1989; 13: 51-57.
5. Burdeny DA, Kroeker MA. CT appearance of the ventral pancreas. J Can Assoc Radiol 1988; 39:
190-194.
6. Zeman RK, McVay LV, Silverman P, et al. Pancreas divisum: thin-section CT. Radiology 1988; 169:
395-398.
7. Rizzo RJ, Szucs RA, Turner MA. Congenital abnormalities of the pancreas and biliary tree in adults.
RadioGraphics 1995; 15: 49-68.
8. Warshaw AL, Simeone JF, Schapiro RH, Flavin-Warshaw B. Evaluation and treatment of the
dominant dorsal duct syndrome (pancreas divisum redefined). Am J Surg 1990; 159: 59-64.
9. Morgan DE, Logan K, Baron TH, Koehler RE, Smith JK. Pancreas divisum: implications for
diagnostic and therapeutic pancreatography. AJR 1999; 173: 193-198.
10. Lindstrom E, Ihse I. Computed tomography findings in pancreas divisum. Acta Radiologica 1989; 30:
609-613.
11. Leyendecker JR, Elsayes KM, Gratz BI, Brown JJ. MRCP: spectrum of pancreatic duct abnormalities.
AJR 2002; 179: 1465-1471.
12. Jadvar H, Mindelzun RE. Annular pancreas in adults: imaging features in seven patients. Abd
Imaging 1999; 24: 174-177.
13. England RE, Newcomer MK, Leung JWC, Cotton PB. Annular pancreas divisum: a report of two
cases and review of the literature. Br J Radiol 1995; 68: 324-328.
14. Inamoto K, Ishikawa Y, Itoh N. CT demonstration of annular pancreas: case report. Gastrointest
Radiol 1983; 8: 143-144.
15. Nguyen KT, Pace R, Groll A. CT appearance of annular pancreas: a case report. J Can Assoc Radiol
1989; 40: 322-323.
16. Glazer GM, Margulis AR. Annular pancreas: etiology and diagnosis using endoscopic retrograde
cholangiopancreatography. Radiology 1979; 133: 303-306.
17. Anderson JR, Wapshaw H. Annular pancreas. Br J Surg 1951; 39: 43-49.
18. Ross BA, Jeffrey RB, Mindelzun RE. Normal variations in the lateral contour of the head and neck of
the pancreas mimicking neoplasm: evaluation with dual-phase helical CT. AJR 1996; 166: 799-801.
19. Neumann CH, Hessel SJ. CT of the pancreatic tail. AJR 1980; 135: 741-745.
20. Stanley RJ, Semelka RC. Pancreas. In: Computed Body Tomography with MRI Correlation, Lee JKT,
Sagel SS, Stanley RJ, Heiken JP, eds. 3rd ed., Lippincott-Raven: Philadelphia, 2000, pp. 873-881.
21. Larsen WJ. Human Embryology. Churchill Livingstone, Inc.: New York, 1993, p. 214.
22. Javors BR, Mori H, Meyers MA, et al. Clinical embryology of the abdomen: normal and pathologic
anatomy. In: Meyers MA, ed. Dynamic Radiology of the Abdomen. Springer-Verlag, Inc., New York,
2000; pp. 32-33.
23. Schulte SJ. Embryology, normal variation, and congenital anomalies of the pancreas. In: Freeny PC,
Stevenson GW, eds. Margulis and Burhenne's Alimentary Tract Radiology, 5th ed. Mosby-Yearbook,
1994, pp. 1039-1049.
24. Lechner GW, Read RC. Agenesis of the dorsal pancreas in an adult diabetic presenting with
duodenal ileus. Ann Surg 1966; 163: 311-314.
25. Gold RP. Agenesis and pseudo-agenesis of the dorsal pancreas. Abdom Imaging 1993; 18: 141-144.
26. Shah KK, DeRidder PH, Schwab RE, Alexander TJ. CT diagnosis of dorsal pancreas agenesis.
JCAT 1987; 11: 170-171.
27. Deignan RW, Nizzero A, Malone DE. Agenesis of the dorsal pancreas: a cause of diagnostic error on
abdominal sonography. Clin Radiol 1996; 51: 145-147.
28. Macari M, Giovanniello G, Blair L, Krinsky G. Diagnosis of agenesis of the dorsal pancreas with MR
pancreatography. AJR 1998; 170: 144-146.
29. Schnedl WJ, Reisinger EC, Schreiber F, Pieber TR, Lipp RW, Krejs GJ. Complete and partial
agenesis of the dorsal pancreas within one family. Gastrointest Endosc 1995; 42: 485-487.
30. Patel S, Bellon EM, Haaga J, Park CH. Fat replacement of the exocrine pancreas. AJR 1980; 135:
843-845.
31. Matsumoto S, Mori H, Miyake H, et al. Uneven fatty replacement of the pancreas: evaluation with CT.
Radiology 1995; 194: 453-458.
32. Applegate KE, Goske MJ, Pierce G, Murphy D. Situs revisited: imaging of the heterotaxy syndrome.
RadioGraphics 1999; 19: 837-852.
33. Hatayama C, Wells TR. Syndrome of externally bilobed lungs with normal bronchial branch pattern,
congenital heart disease, multiple spleens, intestinal malrotation, and short pancreas: an apparently
hitherto undefined malformation complex. Pediatr Pathol 1984; 2: 127-133.
34. Herman TE, Siegel MJ. Polysplenia syndrome with congenital short pancreas. AJR 1991; 156: 799800.
35. Hadar H, Gadoth N, Herskovitz P, Heifetz M. Short pancreas in polysplenia syndrome. Acta
Radiologica 1991; 32: 299-301.
36. Fulcher AS, Turner MA. Abdominal manifestations of situs abnormalities in adults. RadioGraphics
2002; 22: 1439-1456.
37. Sica GT, Reed MF. Diagnosis Please. Case 27: intrapancreatic accessory spleen. Radiology 2000;
217: 134-137.
38. Harris GN, Kase DJ, Bradnock H, Mckinley MJ. Accessory spleen causing a mass in the tail of the
pancreas: MR imaging findings. AJR 1994; 163: 1120-1121.
39. Hayward I, Mindelzun RE, Jeffrey RB. Intrapancreatic accessory spleen mimicking pancreatic mass
on CT. JCAT 1992; 16: 984-985.
40. Agrons GA, Corse WR, Markowitz RI, Suarez ES, Perry DR. Gastrointestinal manifestations of cystic
fibrosis: radiologic-pathologic correlation. RadioGraphics 1996; 16: 871-893.
41. Daneman A, Gaskin K, Martin DJ, Cutz E. Pancreatic changes in cystic fibrosis: CT and sonographic
appearances. AJR 1983; 141: 653-655.
42. Iannaccone G, Antonelli M. Calcification of the pancreas in cystic fibrosis. Pediatr Radiol 1980; 9: 8589.
43. Soyer P, Spelle L, Pelage JP, et al. Cystic fibrosis in adolescents and adults: fatty replacement of the
pancreas CT evaluation and functional correlation. Radiology 1999; 210: 611-615.
44. Willi UV, Reddish JM, Teele RL. Cystic fibrosis: its characteristic appearance on abdominal
sonography. AJR 1980; 134: 1005-1010.
45. Hernanz-Schulman M, Teele RL, Perez-Atayde A, Zollars L, Levine J, Black P, Kuligowska E.
Pancreatic cystosis in cystic fibrosis. Radiology 1986; 158: 629-631.
46. Tjon A Tham RTO, Heyerman HGM, et al. Cystic fibrosis: MR imaging of the pancreas. Radiology
1991; 179: 183-186.
47. Ferrozzi F, Bova D, Campodonico F, et al. Cystic fibrosis: MR assessment of pancreatic damage.
Radiology 1996; 198: 875-879.
48. King LJ, Scurr ED, Murugan N, Williams SGJ, Westaby D, Healy JC. Hepatobiliary and pancreatic
manifestations of cystic fibrosis: MR imaging appearances. RadioGraphics 2000; 20: 767-777.
49. Heindryckx E, Van Steenbergen W, Van Hoe L, Vanbeckevoort D, Ectors N, Baert AL. Solitary true
cyst of the pancreas. Eur Radiol 1998; 8: 1627-1629.
50. Auringer ST, Ulmer JL, Sumner TE, Turner CS. Congenital cyst of the pancreas. J Pediatr Surg
1993; 28: 1570-1571.
51. Daher P, Diab N, Melki I, Abi-Aad G, Korkmaz G. Congenital cyst of the pancreas: antenatal
diagnosis. Eur J Pediatr Surg 1996; 6: 180-182.
52. Zhang XM, Mitchell DG, Dohke M, Holland GA, Parker L. Pancreatic cysts: depiction of single-shot
fast spin-echo MR images. Radiology 2002; 223: 547-553.
53. Girelli R, Bassi C, Falconi M, et al. Pancreatic cystic manifestations in von Hippel-Lindau disease. Int
J Pancreatol 1997; 22: 101-109.
54. Hough DM, Stephens DH, Johnson CD, Binkovitz LA. Pancreatic lesions in von Hippel-Lindau
disease. AJR 1994; 162: 1091-1094.
55. Choyke P, Glenn GM, Walther MM, Patronas NJ, Linehan WM, Zbar B. von Hippel-Lindau disease:
genetic, clinical, and imaging features. Radiology 1995; 194: 629-642.
56. Fukukura Y, Inoue H, Miyazono N, et al. Lymphoepithelial cysts of the pancreas: demonstration of
lipid component using CT and MRI. JCAT 1998; 22: 311-313.
57. Koga H, Takayasu K, Mukai K, et al. CT of lymphoepithelial cysts of the pancreas. JCAT 1995; 19:
221-224.
58. Katz DS, Scatorchia GM, Wojtowycz AR, Botash RJ. Lymphoepithelial cyst of the pancreatic head.
AJR 1995; 165: 489.
59. Goodman P, Kumar D, Balachandran S. Lymphoepithelial cyst of the pancreas. Abdom Imaging
1994; 19: 157-159.
60. Kim YH, Auh YH, Kim KW, Lee MG, Kim KS, Park SY. Lymphoepithelial cysts of the pancreas: CT
and sonographic findings. Abdom Imaging 1998; 23: 185-187.
61. Cubuk M, Arslan G, Ceken K, Ozkaynak C, Luleci E. Schwachman-Diamond syndrome. Acta
Radiologica 2000; 41: 627-628.
62. Wilschanski M, van der Hoeven E, Phillips J, Shuckett B, Durie P. Schwachman-Diamond syndrome
presenting as hepatosplenomegaly. J Pediatr Gastroenterol Nutr 1994; 19: 111-113.
63. Robberecht E, Nachtegaele P, Van Ratinghe R, Afschrift M, Kunnen M, Verhaaren R. Pancreatic
lipomatosis in the Schwachman-Diamond syndrome: identification by sonography and CT scan.
Pediatr Radiol 1985; 15: 348-349.
64. Bom EP, van der Sande FM, Tjon A Tham RTO, Hillen HFP. Schwachman syndrome: CT and MR
diagnosis. JCAT 1993; 17: 474-476.
65. Davies MRQ. Nesidioblastosis: still an enigma. Surg Annu 1992; 24: 231-246.
66. Milner RD. Nesidioblastosis unraveled. Arch Dis Child 1996; 74: 369-372.
67. Shilyansky J, Fisher S, Perlman K, Filler R. Is 95% pancreatectomy the procedure of choice for
treatment of persistent hyperinsulinemic hypoglycemia of the neonate? J Pediatr Surg 1997; 32: 342346.
Montemarano H, Lonergan GJ, Bulas DI, Selby DM. Pancreatoblastoma: imaging features in 10 patients
and review of the literature. Radiology 2000; 214: 476-482.