PLEOMORPHIC HYALINIZING ANGIECTATIC TUMOR OF SOFT PARTS

A case of recently described pleomorphic hyalinizing angiectatic tumor (PHAT) of soft parts is reported. The subcutaneous solid tumor arisin g in the axilla of a 58-year-old man was histologically characterized by sheets of mitotically inactive oval and pleomorphic cells, intranuc lear cytoplasmic inclusions, and clusters of ectatic vessels with peri vascular hyalinization. Mono-and multinucleated giant cells were also present. A hemangiopericytoma-like pattern of vascularity, pseudovascu lar spaces, stromal collagen with degenerative changes, and immunoreac tivity for CD34 were observed. Since these features were very similar to those of solitary fibrous tumors of various sites and newly categor ized giant cell angiofibroma, it is considered that PHAT, solitary fib rous tumor, and giant cell angiofibroma may be in the same family of t umor. The tumor was diploid with a low S-phase fraction. The patient w as well with no evidence of disease for 23 months.