The Korean Journal of Pathology
2006; 40: 377-80
Angiomatoid Fibrous Histiocytoma
- A Case Report -
∙ Jong-Seok Lee1
Kyungeun Kim∙
Kyung-Ja Cho
Departments of Pathology and
1
Orthopedic Surgery, University of
Ulsan College of Medicine, Asan
Medical Center, Seoul, Korea
We report on a case of angiomatoid fibrous histiocytoma located deep in subcutaneous tissue
of the left shoulder in an 11-year-old boy. An ovoid firm mass was slowly increasing in size
for 5 months without any pain or tenderness. The tumor was grossly multicystic, with dense
fibrous capsule and it measured 7.5×7.5×4.0 cm. The locules contained hemorrhagic fluid,
and the inner surface was purplish brown and trabecular. The septal solid areas were cellular, and they consisted of histiocytoid spindle cells that were arranged in a storiform or fascicular pattern. The tumor cells showed immuno-positivity for CD99, CD68 and desmin. These
findings were compatible with angiomatoid fibrous histiocytoma of an uncommon location.
Received : May 9, 2006
Accepted : July 31, 2006
Corresponding Author
Kyung-Ja Cho, M.D.
Department of Pathology, University of Ulsan College
of Medicine, Asan Medical Center, 388-1
Pungnap-dong, Songpa-gu, Seoul 138-736, Korea
Tel: 02-3010-4545
Fax: 02-472-7898
E-mail: [email protected]
Key Words : Angiomatoid fibrous histiocytoma; Shoulder
as a sort of benign hemorrhagic cystic mass. An excision was performed.
Grossly, the tumor was an encapsulated, ovoid, multilocular
cystic mass, and it measured 7.5×7.5×4.0 cm (Fig. 1). The
external surface was brownish tan and smooth. The cut surface
revealed several locules that were filled with hemorrhagic fluid.
The internal surface of the locules was purplish brown, irregular
and trabecular. The thickness of the wall ranged from 0.1 cm to
0.8 cm.
Histologically, the tumor consisted of fairly cellular solid areas
with variable-sized blood-filled cystic spaces (Fig. 2A). The tumor
was surrounded by a fibrous capsule; a dense lymphoplasmacytic
infiltration was present, especially in the peripheral areas, and
those two features mimicked metastatic tumor in a lymph node
(Fig. 2B). The blood-filled clefts or cystic spaces were lined by
flattened tumor cells rather than endothelium proper. A diffuse,
intra- and extracellular deposition of hemosiderin pigments was
another characteristic feature of this tumor (Fig. 2A). The solid
areas consisted of spindle histiocytoid cells with a storiform or
short fascicle pattern. The individual cells had bland looking
ovoid nuclei and elongated cytoplasm (Fig. 2C). Mitotic figures
Angiomatoid fibrous histiocytoma, previously called angiomatoid malignant fibrous histiocytoma, is now considered to be an
intermediate malignancy.1 This tumor is categorized as a tumor
of uncertain differentiation by the 2002 WHO classification.2
Four cases of angiomatoid fibrous histiocytoma that have been
reported in Korea were all less than 3 cm at the greatest dimension, and they were located on the scalp and the upper arm.3-6
Here, we describe another case of angiomatoid fibrous histiocytoma in an 11-year-old boy.
CASE REPORT
An 11-year-old boy was referred to our hospital with an ovoid
mass in his left shoulder. His mother said that the mass had first
been noted five months before, and that it had been slowly increasing in size. Neither pain nor tenderness was present. The magnetic resonance (MR) images showed a well capsulated multilobulating deep subcutaneous mass (8 cm at the greatest dimension) with hemorrhage and fluid-fluid level. There was no evidence of muscle invasion, and the lesion was clinically regarded
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Kyungeun Kim Jong-Seok Lee Kyung-Ja Cho
were rare, but a focal area with mitotic counts up to 3/10 HPF
was present in the periphery of the tumor. On the immunohistochemical staining, the tumor cells showed diffuse positivity
for CD99 and CD68 and focal positivity for desmin (Fig. 3). The
Ki-67 labeling index was up to 10%. The patient has shown no
evidence of persistence or recurrence of the tumor for the postoperative 5 months.
DISCUSSION
Fig. 1. A gross photograph of the tumor, showing an ovoid multilocular cystic mass containing hemorrhagic fluid.
A
C
In 1979, Enzinger described 41 cases of unusual sarcoma of a
fibrohistiocytic lineage, which were characterized by their primary occurrence as nodular subcutaneous growth in the extremities or, more rarely, in the head and neck of young individuals
and children.7 The author named those cases ‘‘angiomatoid malignant fibrous histiocytoma’’ (AMFH), and they were regarded as
a variant of malignant fibrous histiocytoma, based on the presence of metastasis.7 However, according to a report by FanburgSmith et al.,8 the metastatic rate was only 1% in a large study
B
Fig. 2. Photomicrographs of the tumor. (A) Variable-sized bloodfilled cystic spaces are present between tumor cells. (B) A thick
fibrous pseudocapsule and a prominent lymphoplasmacytic infiltration are shown at the periphery of the tumor. (C) Cellular areas
consisting of oval or spindle tumor cells with vesicular nuclei arranged in whorls or ill-defined fascicles.
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Angiomatoid Fibrous Histiocytoma
A
B
C
Fig. 3. The tumor cells show immuno-positivity for CD68 (A), CD99 (B) and desmin (C).
of angiomatoid fibrous histiocytoma. Moreover, Costa and Weiss9
documented that local recurrences were noted only in 12% of
patients. All of the tumors had initially positive resection margins, and they were subsequently cured by re-excision.9 Based
on these reports, the World Health Organization has reclassified
angiomatoid (malignant) fibrous histiocytoma as tumor of uncertain differentiation and intermediate malignancy rather than as
fully malignant sarcoma.2 This tumor typically affects children
and young adults, and it presents as a painless, slowly growing
subcutaneous soft tissue mass that is usually located in the extremities and less commonly in the trunk, head and neck.8 Clinically, it may resemble hematoma, hemangioma or a benign cyst,
as it was in our case.10
Histologically, thick fibrous pseudocapsule around the tumor,
variable-sized pseudovascular spaces between the tumor cells
and a prominent cuff of lymphoplasmacytic infiltration are characteristic features of angiomatoid fibrous histiocytoma. The tumor
cells are arranged in a variety of growth patterns, including sheets,
whorls and short fascicles.10 Individual tumor cells of angiomatoid fibrous histiocytoma look cytologically bland, but in occasional cases, they may show a striking pleomorphism, which
does not appear to have clinical significance.10 The mitotic rate
is low.10
Partial immunopositivity for desmin, epithelial membrane
antigen, CD68 or CD99, which was also be seen in our case, have
been reported in about half of the cases of angiomatoid fibrous
histiocytoma.11-13 This rather nonspecific multiphenotype is attributed to uncertain differentiation of angiomatoid fibrous his-
tiocytoma. Despite its name, this tumor does not express endothelial markers such as CD31, CD34 or factor VIII-related antigen.10
The differential diagnosis of angiomatoid fibrous histiocytoma
includes dermatofibroma with aneurysmal/hemosiderotic changes
(aneurysmal benign fibrous histiocytoma), metastatic tumor in
a lymph node, various vascular neoplasms and Bednar tumor. We
can discriminate angiomatoid fibrous histiocytoma from vascular neoplasms by the lack of endothelium. Bednar tumor contains
melanin pigments, but not hemosiderin pigments. Aneurysmal
fibrous histiocytoma, a variant of dermatofibroma by the 2002
WHO classification, has histologic features similar to angiomatoid fibrous histiocytoma, except the lack of pseudocapsule and
a dense cuff of lymphoplasma cells.2 Although they are classified
into different groups, their essential differences are not at present
clear. Some authors have used these two terms interchangeably.4,6
Fusion of FUS and ATF1 genes has been reported in two cases
of angiomatoid fibrous histiocytoma.14,15 Recently, a case with
fusion of the EWSR1 and ATF1 genes, which was previously
identified in clear cell sarcoma, has been reported.16 Further cytogenetic analysis of more cases will be needed to clarify whether
or not the presence of these fusion genes is pathognomonic for
angiomatoid fibrous histiocytoma.
Death due to the disease is extremely rare in patients with
angiomatoid fibrous histiocytoma.17 Local recurrence has been
reported in 12% of cases in one large study, and it is common
in cases with infiltrating margins, involvement of the skeletal
muscle and the head and neck region.9 A wide surgical excision
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Kyungeun Kim Jong-Seok Lee Kyung-Ja Cho
and a careful follow-up are recommended since there is no evidence that adjuvant therapy may play a role in the primary management of this tumor.10
The present case is different from the four previously reported
Korea cases in respect of the size, which was 7.5 cm in the greatest dimension, and the location in the shoulder. In spite of the
uncommon location, angiomatoid fibrous histiocytoma should
be considered as part of the differential diagnosis of hemorrhagic
cystic mass of soft tissue in young individuals, and the diagnosis can, to a certain extent, be confirmed by immunohistochemical staining.
a vascular neoplasm. Cancer 1979; 44: 2147-57.
8. Fanburg-Smith JC, Miettinen M. Angiomatoid ‘‘malignant’’ fibrous
histiocytoma: a clinicopathologic study of 158 cases and further exploration of the myoid phenotype. Hum Pathol 1999; 30: 1336-43.
9. Costa MJ, Weiss SW. Angiomatoid malignant fibrous histiocytoma.
A follow-up study of 108 cases with evaluation of possible histologic
predictors of outcome. Am J Surg Pathol 1990; 14: 1126-32.
10. Billings SD, Folpe AL. Cutaneous and subcutaneous fibrohistiocytic
tumors of intermediate malignancy: an update. Am J Dermatopathol
2004; 26: 141-55.
11. Fletcher CD. Angiomatoid ‘‘malignant fibrous histiocytoma’’: an
immunohistochemical study indicative of myoid differentiation.
Hum Pathol 1991; 22: 563-8.
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