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Microvenular hemangioma (MVH) is a rare benign vascular tumor with a controversial etiology, but hormone receptor alterations might be involved. We report a case of MVH in a 41‐year‐old Taiwanese woman who presented with a 1.5 × 1 cm violaceous plaque on left thigh that had appeared 1 year previously. She had taken oral contraceptives for several years and stopped 1 year prior to presentation. Histologically, the tumor was composed of small and compressed venous structures infiltrating in the dermis and subcutis. Immunohistochemically, the tumor cells displayed negative immunoreactivity for human herpesvirus‐8 and positive immunoreactivity for smooth muscle actin and progesterone receptor (PR). Taken together with the patient's medical hormone therapy history and the evidence of PR immunoreactivity, our findings support that progesterone may be associated with the tumorigenesis of MVH. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Abstract: Microvenular hemangioma (MH) is not a very common type of hemangioma, and it can occasionally be difficult to distinguish it from other benign vascular tumors and malignant tumors such as Kaposi''s sarcoma. The latter has been shown to be negative for the marker D2-40. Nevertheless, the status of MH for D2-40 has not been established yet. We therefore studied the expression of podoplanin in three cases of MH using D2-40 antibody. No expression was seen, while the dermal lymphatics were clearly immunostained. Nevertheless, the vessels of the MHs were positive for CD34, CD31, and von Willebrand Factor. This study adds MH to the list of vascular lesions that fail to express the allegedly lymphatic marker podoplanin. [Copyright &y& Elsevier]

The current study reports a case of multiple microvenular hemangioma (MH). A 35-year-old male presented with dark red maculopapules on the trunk and limbs that had been apparent for 5 years. The number of lesions exceeded 100 in total. A histological examination demonstrated multiple, irregular, branching venules in the dermis, without any endothelial atypia. On immunohistochemical analysis of the vascular structures, the endothelial cells stained positive for CD31, CD34 and factor VIII, and the perivascular cells stained positive for SMA and HHF-35. These observations were consistent with a diagnosis of MH, and should be differentiated from the most common differential diagnosis of patch-stage Kaposi's sarcoma. There was no clear effect following topical application of recombinant human inter-feron α-2b gel. [ABSTRACT FROM AUTHOR]