Transcript Diapositiva 1

LIPOMATOUS HAEMANGIOPERICYTOMA:
A CASE REPORT.
NUNZIA SCIBETTA - LORENZO MARASA’
Department of Pathology, A.R.N.A.S. Civico, Palermo
INTRODUCTION
 Lipomatous haemangiopericytoma (L-HPC) is an
unusual tumor composed of mature adipocytes and
HPC-like branching vessels, that shares many features
with solitary fibrous tumour (SFT).
 L-HPC present preferentially as deep-seated, (deep soft
tissues of the lower extremity and retroperitoneum),
well demarcated, slow-growing, almost non–recurring,
non-metastasizing masses. They occur in middle-aged
adults with a male predilection.
 We describe the clinicopathologic and immunohistochemical features of a case of L-HPC, located in the
retroperitoneum, wich contained hypercellular areas
and showed increased mitotic activity and nuclear
atypia.
METHODS
 A 60 year old woman had a painless mass on the
retroperitoneum with visceral compression symptoms. Clinical examination did not give any indication of metastasis.
 The surgical specimen was fixed in buffered formalin,
embedded in paraffin and stained with H&E. Immunohistochemical studies were performed.
RESULTS
 Grossly the tumor was well-demarcated and partially
encapsulated, solid, tan yellow, with maximum diameter of 29 cm, with free margins.
 Histologically it was composed of a admixture of benign lipomatous and haemangiopericytomatous components, including oval to round cells, surrounding a
sinusoidal and staghorn vasculature with perivascular
hyalinization. Mature fat occupied approximately one
quarter of the area of tumour.
 The tumour contained hypercellular areas showed 10
mitoses per 10 HPF, and moderate to severe nuclear
atypia.
 Neither lipoblasts, nor isolated atypical hyperchromatic cells within mature fat as are seen in well-differentiated liposarcoma, were present.
 Immunohistochemically, they stained with antibodies
to vimentin, CD34, BCL2, CD57, CD99, and not to alpha-smooth muscle actin, desmin, S100 protein, EMA,
CD31,CD117.
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Features of solitary fibrous tumour in
addition to foci of mature adipocytes
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An intimate admixture of bland spindle cells and mature adipocytes
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Cellular area with mitotic activity and
cytological atypia
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IMMUNOHISTOCHEMICAL EXAMINATION
Diffuse positivity for CD34
There is no staining for
smooth muscle actin
Immunoreactivity of the
tumour cells for CD57
Immunoreactivity for
vimentin
CONCLUSIONS
 The histologic differential diagnosis of this neoplasm
includes spindle-cell lipoma, angiolipoma, liposarcomas, tumors showing smooth muscle and adipocytic
differentiation, and haemangiopericytoma infiltrating
fat. Histologically the our tumor resemble the cellular
form of L-HPC and the immunoprofile is also similar to
that of L-HPC.
 Because of the small number of cases and limited
follow-up, we cannot be certain of their biologic
behavior .Criteria of malignancy include large tumour
size, high cellularity, at least moderate to marked
cytological atypia, tumor necrosis, numerous mitoses
>4 mitoses per 10 HPF and /or infiltrative margins.
CONCLUSIONS
 In our case the large tumor size, the presence of areas
of increased cellularity with a mitotic index >4 mitoses
per 10 HPF, and nuclear atipya are important predictors
of poor outcome, and long-term follow-up is mandatory.
MAIN REFERENCE :
Guillou L:, Gebhard S. , Coindre JM. : Lipomatous
hemangiopericytoma: a fat-containing variant of solitary
fibrous tumor? Clinicopathologic, immuno-histochemical, and ultrastructural analysis of a series in favour of
a unifying concept. Hum. Pathol. 31; 1108-1115; 2000.