ABSTRACT:
Angiomatoid fibrous histiocytoma (AFH) is a rare soft tissue neoplasm of
intermediate biologic potential that occurs mostly in extremities and is
often misdiagnosed initially, because of its clinical and radiological
similarity to other diseases.1-4 .Clinically it is
very difficult to differentiate it from other tumors like angiosarcoma
or a simple organised hematoma 2 .Similarly,
Histopathology is not always revealing. Surgery is the mainstay of
management and can effectively control local recurrence and metastasis
if planned beforehand. Herein ,we describe a case report of a
55 year-old female who presented with a swelling in the popliteal region
which on clinical and radiological evaluation revealed a popliteal cyst
and was managed by an unplanned excisional biopsy. We present this case
to emphasize to clinicians that the chances of improper management of
such tumors with unplanned excision are high , if such differentials are
not kept in mind preoperatively.
INTRODUCTION:Angiomatoid fibrous Histiocytoma(AFH) is a rare soft tissue tumor with
intermediate biologic potential that is commonly found in the
extremities of children , adolescents and young adults in deep dermis
and subcutaneous plane1,2,4,5 .It was initially
described as angiomatoid malignant fibrous histiocytoma by
Enzinger1 ,but it is no longer regarded as malignant
because of its benign appearance and favourable
prognosis2,5 .Because of its indolent clinical
presentation and radiological features , it is often misdiagnosed for a
benign condition such as a hematoma, hemangioma or simple cysts leading
to inappropriate treatments such as unplanned
excision5. Although the prognosis of AFH is not poor ,
it recurs in up to 15 % of cases and metastasizes in fewer than 1 % of
cases2 .So, keeping AFH as a differential in cases
with soft tissue masses can guide us to do an extended resection of the
tumor with wide margins and minimise the chances of recurrence.
CASE PRESENTATION :
A 45 year old female presented to us with a history of right knee pain
for 6 months and swelling in the posterior aspect of the knee for 1
year, which has been gradually increasing in size. The patient had
difficulty squatting and sitting cross-legged . There were no
constitutional symptoms. Past medical, surgical and family history were
not significant. On examination, there were two soft cystic , fluctuant,
non-tender swelling , each around 7*5 cm arising from the posteromedial
aspect of the right knee lying longitudinally in craniocaudal fashion
(Figure 1).There were no skin changes .USG findings revealed a fluid
filled , well circumscribed, dumbbell shaped mass with 2 cysts,
each of sizes around 6*5*3 cm communicating with each other arising
from the posteromedial knee with a neck at its deepest extent, extending
into the joint space between the semimembranosus and medial head of
gastrocnemius suggestive of popliteal cyst. The patient underwent en
bloc surgical excision(Figure 2,3,4) .On histopathological examination,
the lesion demonstrated characteristic features of Angiomatoid Fibrous
Histiocytoma including multinodular growth of myoid spindled or
histiocytoid cells with a distinctive syncytial appearance,
pseudo-angiomatous spaces filled with blood and surrounded by tumour
cells , a thick fibrous pseudo capsule with peritumoral
lymphoplasmacytic cuffing with occasional germinal center formation,
areas of prominent hemosiderin deposition and foam cells within the
tumour cells (Figure 5,6). Immunohistochemistry for supporting the
diagnosis was planned but due to resource constraints, we could not
manage the same.