ANATOMIC PATHOLOGY
Case Report
Paratesticular Multicystic Mass of Wolffian,
Probably Paradidymal, Origin
ALAN R. SCHNED, MD, 1 GEORGE M. SEREMETIS, MD, 2 AND STEPHEN N. ROUS, MD 2
A unilateral multicystic mass in the connective tissue adjacent to the
vas deferens in a 46-year-old man is reported. Anatomically, it was
distinct from the epididymis and vas and contained no sperm. The epithelial lining was simple, ciliated, and cuboidal to columnar. The cysts
were surrounded by connective tissue collars containing smooth muscle.
The authors postulate that this lesion represents a cystic hyperplasia of
vestigial Wolffian duct remnants, based on its unique histologic features and the exclusion of other plausible explanations. The supraepididymal, paravasal location suggests origin in the paradidymis. (Key
words: Epididymis; Mesonephric duct; Mesonephric hyperplasia; Mesonephric remnants; Paradidymis; Vas deferens; Wolffian duct) Am J
Clin Pathol 1994;101:543-546.
Excluding spermatoceles and hydroceles, extratesticular scrotal cystic lesions are rare. Epididymal cystadenomas, cysts of
the tunica albuginea, and cystic mesotheliomas probably constitute the primary differential diagnoses.
We recently encountered a patient with a unilateral florid
multicystic lesion located along the spermatic cord, which, to
our knowledge, had not been previously described. Based on its
anatomic location and histopathologic features, together with
the exclusion of other plausible alternatives, we determined
that this lesion was histogenetically of Wolffian duct origin,
probably related to the paradidymis.
tion tests (T3 resin uptake, T4, thyroid stimulating hormone), follicle
stimulating hormone (FSH), luteinizing hormone, prolactin, testosterone, and /3-human chorionic gonadotrophic hormone. The serum FSH
(18 mlU/mL) was at the upper limit of the reference range (4-18 mlU/
mL), and the serum testosterone (5.5 ng/mL) was low-normal (reference range 3-12 ng/mL). All other results were within normal limits.
The patient desired sterilization, and vasectomy and excision of the
mass and the right epididymis were performed. During surgery, a complex multicystic mass was found adjacent to the right vas deferens and
epididymis. The left side was explored and found to be normal.
CASE
PATHOLOGIC FINDINGS
The patient was a 46-year-old father of four who complained of a
mass in the right scrotum that had been slowly enlarging over several
months. He had had some discomfort and had noted a probable mass
present for 7 or 8 years. On physical examination, tenderness, swelling,
and induration along the scrotal portion of the right vas deferens were
present. Both testicles were descended, and the left side was normal to
palpation. The'patient had no known in utero exposure to maternal
diethylstilbestrol, history of trauma or infection, or previous orchiopexy or other scrotal surgery.
Other medical history included disabling, seropositive rheumatoid
arthritis for 20 years. He had been treated in the past with aspirin,
prednisone, nonsteroidal antiinflammatory agents, and methotrexate.
At the time of examination, he was receiving weekly intramuscular
gold injections. He also had undergone an appendectomy in the remote
past and had a several-month history of unilateral gynecomastia.
Work-up of the gynecomastia included fine-needle aspiration biopsy
and serologic endocrine evaluation. The latter included thyroid func-
The specimen consisted of the right epididymis, a portion of
proximal right vas deferens, and attached cremasteric fascial
tissue. Within the latter was an irregular mass composed of
numerous fluid-filled cystic cavities, which resembled a bunch
of grapes (Fig. 1). The overall dimensions of the mass were
approximately 7.5 X 5 X 1.5 cm, and the individual cysts measured .3-1.5 cm in diameter. The cysts were smooth-walled
and unilocular. On section, they exuded a slightly yellowish,
slightly turbid fluid. The cystic mass was clearly demarcated
from both the epididymis and the vas deferens.
Microscopically, the multiple cysts varied in size. Some were
small and clustered, but most were larger and occasionally
slightly compressed (Fig. 2). The luminal configurations were
sometimes smooth, but more often wrinkled or undulating;
papillae, however, were not identified. In all cysts, the lining
consisted of a single layer of cuboidal to columnar cells. Individual ciliated cells with prominent terminal bars were interspersed at irregular intervals (Fig. 3). Nuclei were bland, regular, and basally oriented. A conspicuous collar-like zone of
condensed
connective tissue surrounded many cysts, and disFrom the Departments of'Pathology and 2Surgery (Urology), Dart- tinct bundles of smooth muscle constituted a portion of the
mouth-Hitchcock Medical Center, Lebanon, New Hampshire, and Vet- mantle around many of these cysts (Fig. 2). The smooth muscle
erans Affairs Medical Center, White River Junction, Vermont.
element was confirmed by Masson trichrome stain.
No spermatozoa were identified in any of the cysts, and no
Manuscript received November 16, 1992; accepted January 8, 1993.
sperm granulomas, foreign body reactions, scarring, or inflamAddress reprint requests to Dr. Schned: Department of Pathology,
mation were found. The ductuli efferentes, ductus epididymis,
Dartmouth-Hitchcock Medical Center, One Medical Center Drive,
and vas deferens were completely unremarkable, and no conLebanon, NH 03756.
543
544
ANATOMIC PATHOLOGY
Case Report
FIG. 1. Multicystic tabulated mass in paravasal tissues. The cysts are
glistening, distended, and variable in size. A portion of epididymis, at
the left edge of the specimen, is distinctly separate from the cystic mass.
FIG. 3. The cysts are lined by a simple cuboidal to low-columnar epithelium. Scattered ciliated cells are interspersed (arrows). Hematoxylin
and eosin, X 400.
nection was found between the cystic proliferation and these
structures.
anatomic location adjacent to the spermatic cord and cremasteric fascia, but without any connection to the epididymis or
cord itself.
The presence of the epithelial lining excludes a mesenchymal
origin. A mesothelial origin also seems unlikely. Mesothelial
cysts may be multiple and have been reported both within the
testicular tunics as well as along the epididymis or spermatic
cord.1,2 The lining of mesothelial cysts consists of a single layer
of cuboidal or flattened mesothelial cells. The surrounding fibrous tissue may be hyalinized, but a pericystic smooth muscle
component has not been reported. Likewise, ciliation has not
been described.
The common hydrocele, a mesothelial-lined serous fluid accumulation between the parietal and visceral tunica vaginalis,
may become multiloculated following chronic inflammation
and fibrosis. As with mesothelial cysts, however, hydroceles
have neither a columnar cell lining with cilia nor smooth muscle-containing collars of connective tissue. Rarely, an adenomatoid tumor, thought to be of mesothelial origin, may present
as a cystic lesion in association with a hydrocele. These tumors,
however, retain their distinctive tubular histologic pattern, unlike in the present case.
The most common paratesticular cystic lesion of epithelial
origin is probably the spermatocele. The spermatocele is considered an acquired cystic dilatation generally arising from the
rete testis or head of the epididymis. Like the hydrocele, it may
be multiloculated. Like the present case, the connective tissue
wall is fibromuscular (although generally not well organized
into compact collars), and cilia are often evident. However, the
fluid in a spermatocele contains sperm, and, by definition, an
anatomic connection to the epididymis is evident. Neither of
these features were elements of the case described herein.
Marked cystic dilatation of the epididymis may also occur
secondary to trauma or obstruction and has been reported as a
sequela of vasectomy.3 In our case, both the absence of an
attachment to the epididymis and the appropriate clinical history exclude these explanations from consideration. For the
same reasons, the rare epididymal cystic dilatation seen in male
offspring exposed in utero to maternal diethylstilbestrol use,4
the cystic transformation of the rete testis reported in associa-
DISCUSSION
Within the paratesticular area are a variety of tissues from
which cysts may originate. These include epithelial, mesothehal, vestigial, and mesenchymal structures. A few common and
a larger number of uncommon entities enter into the consideration of the histogenesis of a given paratesticular cystic lesion.
Several salient features of the cystic lesion described in this
report help narrow the differential diagnosis. These features
include multicystic change, a columnar epithelial lining with
intermittent ciliation, periglandular collars of connective tissue
containing smooth muscle, the absence of spermatozoa, and an
FIG. 2. Portions of several cysts of variable size. Some of the cysts are
surrounded by conspicuous collar-like zones of connective tissue, focally containing prominent smooth muscle (arrows). Hematoxylin and
eosin, X 100.
A.J.C.P. • April 1994
SCHNED, SEREMETIS, AND ROUS
545^
Multicystic Paradidymal Mass
tion with renal failure,5 and the epididymal distention due to
plugging by inspissated fluid in Young's syndrome 6 are also
excluded.
Several epithelial neoplasms that are predominantly cystic
occur in the paratesticular region. The papillary cystadenoma
of the epididymis, which when bilateral is associated with von
Hippel Lindau syndrome, 7 has a unique architectural and histological pattern, unlike that in the present case.8 The rare adenocarcinomas of the rete testis9 and epididymis 10 may be multicystic or associated with hydroceles and thus may present as
cysts, but both entities are characterized by invasive growth
patterns and malignant cytologic features.
The last series of paratesticular structures from which cystic
lesions might arise are the vestigial appendages. Those considered remnants of Mullerian duct origin include the appendix
testis, found in the groove between the superior pole of the
testis and the head of the epididymis; the Walthard's rest,
which may be found either in the testicular tunics or the epididymis; and microscopic glandular inclusions, which may occasionally be noted along the spermatic cord or in inguinal hernial tissues." Microscopically, the appendix testis consists of a
cuboidal to low-columnar epithelium overlying a stromal core
that may contain tubular or cystic inclusions with a similar
lining. The epithelium may be ciliated in these Mullerian structures,12 and collars of connective tissue devoid of smooth muscle may be seen around the glandular inclusions.11,13
Rare paratesticular cystic neoplasms with a Mullerian appearance have been reported, with the suggestion that they are
derived from these Mullerian vestigial remnants. 1415 These include serous and mucinous cystadenomas and cystadenocarcinomas, some in the borderline category. In all these lesions,
the epithelium demonstrates characteristic papillae and varying degrees of nuclear atypia. The absence of these latter features distinguishes the present case from these Mullerian-derived neoplasms.
The remaining paratesticular vestigial remnants are thought
to be of Wolffian duct origin. These include the appendix epididymis, the cranial and caudal vasa aberrantia, and the paradidymis. The first three are found attached to the epididymis,
which is itself of Wolffian derivation. The appendix epididymis
has been known to become dilated with serous fluid and thus
manifest as a paratesticular cystic mass.1 All three of these
Wolffian structures contain tubules or cysts lined by an epithelium of cuboidal to columnar cells that may be ciliated, generally situated in a loose connective tissue.12 Despite the close
histologic similarity, the lesion in the present case was probably
not derived from one of these Wolffian remnants, specifically
because it lacked any anatomic connection to the epididymis.
This lesion most likely arose from the paradidymis, which is
the only Wolffian structure that is found unattached to the
epididymis. Its customary location is in the spermatic cord
connective tissue superior to the head of the epididymis. Thus,
its location conforms to the supraepididymal, paravasal lesion
of the present case.
The histologic composition of the paradidymis is the same as
that of the other Wolffian vestiges.16 The presence of a smooth
muscle component in the peritubular stromal cuff or collar in
the paradidymis was emphasized in the study by Walker and
Mills." This feature was specifically noted to distinguish the
paradidymis from vestiges of Mullerian origin and from glandular inclusions found incidentally in hernia sacs and along
spermatic cords. The finding of smooth muscle in the pericys-
tic connective tissue collars in the present case is thus compelling evidence in favor of a Wolffian origin.
To our knowledge, a multicystic benign mass of paradidymal origin had not been previously reported. Indeed, specific
pathologic processes directly ascribed to the paradidymis are
extremely rare, including only two cases of torsion.17 Of additional interest is the report by Wollin and colleagues,18 who
describe three cases of so-called aberrant epididymal tissue, one
of which was grossly cystic. The authors argue that, in two of
the cases, the aberrant epididymal tissue represented the inferior ductus aberrans; in the third case, microscopic epididymal
tissue found in a hernia sac in an 18-year-old man was attributed to either the superior ductus aberrans or the paradidymis.
Histologic description is scanty, but some or all of these lesions
may best be regarded as of Wolffian vestigial origin, rather than
as aberrant epididymal tissue per se.
Aside from the histogenesis, the pathogenesis of this lesion
was also problematic. No obvious cytologic or architectural
features of neoplasia were found, and the lesion resembled no
well-recognized tumor occurring in the paratesticular region.
There was no accompanying inflammation or scarring to suggest a sequela of a traumatic, obstructive, or inflammatory insult. Rather, the consistency of the organization of the multiple
cysts, each lined by a simple epithelium without papillae and
each with a mantle of fibromuscular connective tissue, suggested a cystic hyperplasia.
The coincidental occurrence of gynecomastia in this patient
raises the possibility of a relative estrogen excess or a decrease
in the testosterone:estrogen ratio. This may be supported by
the slightly elevated serum FSH associated with low-normal
testosterone. These changes are far from diagnostic, however,
and the remainder of the serologic endocrine battery was normal. Furthermore, the unilaterality of both the gynecomastia
and the paratesticular mass raises the possibility of local, rather
than systemic, causative factors. Thus, the actual stimulus for
cystic hyperplasia in this Wolffian structure remains conjectural. Nonetheless, this case suggests that the paradidymis or
other Wolffian vestigial structures are, rarely, capable of undergoing clinically important secondary changes.
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