Multiple enchondromas associated with spindle-cell hemangioendotheliomas. An overlooked variant of Maffucci's syndrome.

Maffucci's syndrome is classically defined as the association of multiple enchondromas and hemangiomas. Spindle-cell hemangioendothelioma (SCH), a recently described vascular tumor of purported low malignant potential, has both cavernous hemangioma and Kaposi-like features. We report six patients with Maffucci's syndrome in whom all vascular lesions were SCH. The enchondromas involved the small and long tubular bones of the extremities in all of these patients; flat bones were also involved in three patients. The SCH usually arose in the extremities, distal to the knees and elbows. Five of the six patients had multiple and separate nodules of SCH, and in four patients there was recurrent or persistent SCH within 6 months to 4 years after initial removal. One patient also had a vascular tumor in the spleen mainly with features of a low-grade angiosarcoma with separate SCH-like foci. None of the SCH have metastasized within a follow-up period averaging 20 years. Five patients are alive 14 to 31 years after presentation. One patient died from metastatic dedifferentiated chondrosarcoma. The patient with the low-grade splenic angiosarcoma is alive approximately 2 years after diagnosis. Reappraisal of the older literature suggests that some of the vascular tumors occurring in Maffucci's syndrome, previously diagnosed as hemangiomas, may in fact be SCH. The apparent association between Maffucci's syndrome and SCH, the presence of SCH in other congenital syndromes, and the young patient age and multicentric distribution of SCH unassociated with Maffucci's syndrome raise the possibility that SCH may be a manifestation of a congenital mesodermal disorder with a genetic background related to Maffucci's syndrome. Although the behavior of SCH appears to be one of a locally recurrent or persistent multicentric lesion that does not metastasize, the association of SCH-like foci in a low-grade angiosarcoma of the spleen raises the possibility that SCH may rarely be associated with a higher grade lesion. Therefore, SCH, at least in the setting of Maffucci's syndrome, should be carefully monitored.