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.
