Primary pseudomyogenic hemangioendothelioma of the vulva: a rare location for a rare entity

BACKGROUND: Pseudomyogenic hemangioendothelioma (PMHE) is a recently described vascular neoplasm which typically occurs in the lower extremities of young to middle-aged adults. CASE PRESENTATION: We present here a unique case of PMHE arising primarily in the vulva of a 51-year-old woman who presented with a painful vulvar nodule. Clinically, it was thought as Bartholin gland cyst, vulvar hematoma or papilloma. On surgery, two nodules were found with one located in the superficial dermis and the other in the deep subcutis. Histologically, these two nodules showed similar features, composed of fascicles or sheets of plump spindled to epithelioid cells with eosinophilic cytoplasm. Given the morphological resemblance to a myogenic tumor, the lesion was initially diagnosed as a rhabdomyosarcoma by the referring pathologist. However, a comprehensive reevaluation of the submitted slides made us reconsider a PMHE, which was subsequently confirmed by immunohistochemical study. CONCLUSION: This case demonstrates that PMHE can also develop in the female external genitalia albeit extremely rare. This disease should be included in the differential diagnostic list of vulvar tumors with spindled to epithelioid morphology and cytokeratin-positive immunophenotypes.