Pathology of Pleomorphic
Hyalinizing Angiectatic Tumour
Syn: Pleomorphic Hyalinizing Angiectatic Tumour of Soft Parts
Pleomorphic hyalinizing angiectatic tumour is a rare tumour of uncertain lineage. It was first described in 1996 in a series of 14 cases.
It is a low-grade sarcoma which may recur locally. Metastasis has not been recorded.
Site: The tumour is seen in the subcutaneous tissue of the distal extremities in adults. It is commonly noted on the ankle and feet.
Gross: These are circumscribed or infiltrative lesion. Most tumours have a lobulated appearance with a variegated, tan-brown hemorrhagic cut surface.
Cystic and myxoid changes may be present.
1. Clusters of dilated thin-walled vessels with fibrinoid change of their wall with superimposed thrombosis & occasionally hemosiderin-laden macrophage.
2. Intervening stroma contain spindle shaped cells & bizarre polygonal multinucleate cells.
These multinucleate cells show marked nuclear pleomorphism, hyperchromasia and frequently intranuclear inclusions.
In rare cases psammomatous calcifications may be noted.
3. A variable inflammatory background mainly composed of lymphocytes, plasma cells, and numerous mast cells.
Immunohistochemistry: Multinucleate cells are CD34 positive (50% cases) but negative for S-100 protein, actin and desmin.
3. Primary cutaneous myxofibrosarcoma (Primary cutaneous myxofibrosarcoma mimicking pleomorphic hyalinizing angiectatic tumor (PHAT): a potential diagnostic pitfall.Am J Dermatopathol. 2005 Aug;27(4):322-6.)
5. Some early cases may be mistaken for spindle cell lipoma, benign fibrous histiocytoma or nodular fasciitis.
Local recurrence is common in almost 50% of cases.
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