EPITHELIOID HEMANGIOENDOTHELIOMA OF SKIN AND SOFT-TISSUES - CLINICOPATHOLOGICAL AND IMMUNOHISTOCHEMICAL STUDY OF 30 CASES

Epithelioid hemangioendothelioma of soft tissues (EHE) represents a di stinct entity with an unpredictable clinical course. We analyzed the c linicopathologic and immunohistochemical features in a series of 30 pa tients. Patient age range was 16-74 years (median 50); 18 of 30 patien ts were female. Eight tumors arose in the lower and two in the upper e xtremities, seven on the trunk, five each in the head/ neck and anogen ital regions, two in the mediastinum, and one in the abdomen. Seventee n neoplasms were located in deep soft tissues, nine were subcutaneous or perifascial, and four were dermal; size ranged from 0.4 to 10 cm; i n 11 cases the tumor was >5 cm. Tumors with an infiltrative growth pat tern were more common than entirely circumscribed lesions. The tumors were composed histologically of short strands, cords, or small cluster s of epithelioid, round, to slightly spindled endothelial cells that f ormed at least focally, intracellular lumina and were set in a frequen tly myxohyaline stroma. Thirteen of 30 lesions showed angiocentric gro wth, which was occlusive in many cases. Immunohistochemically, all cas es tested were positive for at least one endothelial marker (CD31, CD3 4, factor VIII, Ulex europaeus), six of 23 (26%) were positive for cyt okeratin, and five of 11 (45%) were positive for alpha-smooth muscle a ctin. Median follow-up of 36 months (range 2-96) in 24 cases showed lo cal recurrence in three cases and systemic metastases in five cases (2 1%); four patients (17%) died of tumor. Although more aggressive histo logic features (striking nuclear atypia in eight cases, numerous spind led cells in 10, more than two mitoses per 10 high-power fields in nin e, and small, more solid angiosarcomalike foci in four cases) tended t o be related to poor clinical outcome, there was no clear correlation. Two metastasizing cases showed no histologically atypical features wh atever. We suggest that EHE of soft tissue is better regarded as a ful ly malignant, rather than borderline, vascular neoplasm, albeit the pr ognosis is better than in conventional angiosarcoma.