Epithelioid hemangioma of small tubular bones: a report of three cases, two of them associated with pregnancy.

We report three cases of epithelioid hemangioma of small tubular bones in women aged 20, 24, and 50 years. In two patients, the tumor appeared during or shortly after pregnancy. We studied clinical data, radiographs, and hematoxylin- and eosin-stained slides, and we performed immunohistochemical and flow cytometric DNA analysis. The tumor was in distal phalanges of the fingers in two patients and in metatarsal bone in one. Cortical bone destruction with infiltration of the surrounding soft tissue was seen in all of the patients. Light microscopic examination showed characteristic morphology, highlighted by epithelioid endothelial cells with different degrees of vasoformativity. Immunohistochemically, the epithelioid cells showed strong positive reaction for Factor VIII in all three patients, for CD31 in two, and for CD34 in one. Ulex europaeus antigen and keratins were negative. Laminin and collagen IV delineated innumerable predominantly abortive vascular structures, which were encircled by cells that presumably were pericytic and that were positive for smooth muscle actin. A relatively high degree of immunostaining for proliferating cell nuclear antigen and Ki67 contrasted with the low mitotic rate and low percentage of cells in S phase. Progesterone and estrogen receptors were negative. Epithelioid hemangiomas of small tubular bones are rare lesions that are characterized by early bone destruction and infiltration of soft tissues. Their association with pregnancy may be fortuitous; if any gestation-related proliferative stimulation exists, it does not seem to be mediated through steroid receptors.