SPINDLE-CELL HEMANGIOENDOTHELIOMA - AN ANALYSIS OF 78 CASES WITH REASSESSMENT OF ITS PATHOGENESIS AND BIOLOGIC BEHAVIOR

Seventy-eight cases of spindle cell hemangioendothelioma (SCH) were st udied to reevaluate its pathogenesis and determine its long-term behav ior. Most of the original findings were confirmed by this study, The t umor occurred at all ages (8-78 years; median, 32 years; mean, 34 year s). Males and females were equally affected. The tumor developed as a superficially located mass of the distal extremities (upper, 32 cases; lower, 30 cases). Four patients (5%) also had Maffucci's syndrome. Th e lesions were circumscribed red-brown masses occasionally containing phleboliths that consisted of cavernous blood spaces alternating with cellular areas consisting of collapsed vascular spaces separated by sp indled fibroblastic eels. Often the endothelium lining the collapsed b lood spaces appeared epithelioid with cytoplasmic vacuolization. The s pindled fibroblastic cells lacked significant atypia and had at most a low level of mitotic activity, As a significant departure from what w as originally reported, more than half of these cases (58%) were parti ally or completely intravascular, The vein containing the tumor often had an irregularly attenuated wall with small intimal herniations and intimal papillae traversing the lumen, Similar intimal changes in adja cent vessels suggest that SCH grows as a multifocal or contiguous proc ess within vessels. Follow-up information was obtained in 40 cases, ra nging from 1 month to 40 years (mean, 5.4 years). Despite conservative excisions In most patients (simple excision, 83%; wide local excision , 13%; amputation, 2%), prognosis was excellent, Fifty-eight percent e xperienced recurrences, but no patient developed metastasis and no pat ient died of the direct effects of the tumor, although one patient wit h Maffucci's syndrome developed a concurrent angiosarcoma, We conclude that SCH is a primary benign vascular neoplasm or malformation simila r to angiomatosis in which alterations in blood flow might explain sam e of the secondary features, Areas of diminished blood flow result in vascular collapse with formation of the ''cellular'' zones, and areas of vascular engorgement with stasis promote thrombosis and organizatio n. Local ''recurrences'' probably represent contiguous spread along or multifocal involvement of a vessel. Because there is no evidence that this lesion has metastatic potential, we suggest that the lesion be d esignated spindle cell hemangioma for solitary lesions and spindle cel l hemangiomatosis for multifocal lesions.