PLEOMORPHIC HYALINIZING ANGIECTATIC TUMOR OF SOFT PARTS - A LOW-GRADENEOPLASM RESEMBLING NEURILEMOMA

Fourteen examples of an unusual mesenchymal tumor characterized by she ets and fascicles of mitotically inactive, hemosiderin-stippled, spind led, and pleomorphic cells, situated around an angiectatic vasculature , are described. The 14 tumors developed in eight women and six men (a ged 32-83 years) and ranged in size from 2.3 to 8 cm. Eleven cases pre sented in the subcutaneous tissues, of which eight were located in the lower extremity. All featured prominent clusters of thin-walled ectat ic vessels surrounded by perivascular hyaline material representing a combination of fibrin and collagen. In three cases the perivascular hy alinization was so extensive that it constituted more than half of the total tumor area. The tumor cells were similar to those of malignant fibrous hystiocytoma but differed from them by the presence of promine nt intranuclear cytoplasmic inclusions, the extreme scarcity of mitoti c figures, and the occasional presence of CD-34 expression. These tumo rs also shared several features with neurilemomas, such as their unusu al vasculature, intranuclear cytoplasmic inclusions, lack of mitotic f igures and abundance of mast cells. They could be distinguished from n eurilemomas, however, by the usual presence of infiltrative margins an d the absence of S-100 protein, Follow-up information on eight patient s (6 months to 25 years) indicated recurrences in four cases, with one of the three patients experiencing numerous recurrences over a 25-yea r period. No patient has developed metastases, however. We suggest tha t this tumor is a low-grade sarcoma of uncertain lineage in which the vascular changes are, in part, reflective of its slow growth.