Microvenular hemangioma: a clinicopathologic review of 13 cases

Background: Microvenular hemangioma is an uncommon benign vascular tumor that can potentially be mistaken for malignancy.

Methods: We reviewed the histopathologic and clinical features of 13 microvenular hemangiomas, which represents the largest series reported to date.

Results: The patients [female (F) = 8 and male (M) = 5] had a mean age of 39 years (range: 16 months-69 years). All presented with a similar history of a new, asymptomatic, stable or slow-growing, red to purple plaque or nodule. The lesions were located on the extremities, chest, back or abdomen. Two patients had multiple lesions. In six, a vascular tumor was not suspected clinically. Histologically, all were composed of a dermal proliferation of thin-walled, often branching, vascular channels dissecting through collagen fibers. The vessels were surrounded by a conspicuous layer of pericytes. Immunohistochemistry showed that all were positive for a vascular marker. Stains for WT-1 were positive in 9 of 10. None of the lesions tested (0/12) were positive for podoplanin or human herpesvirus-8 (HHV-8) (0/9). Follow-up available on six patients showed no recurrences.

Conclusion: The histomorphology of microvenular hemangioma frequently raises concern for a malignant vascular lesion, especially Kaposi sarcoma. Identification of characteristic features, particularly the pericyte layer in routinely stained sections or with an SMA immunostain, allows an accurate diagnosis.