Epstein‐Barr virus–associated smooth muscle tumor presenting as a vulvar mass in an acquired immunodeficiency syndrome patient: a case report

Smooth muscle tumors in immunocompromised patients have a strong association with Epstein‐Barr virus (EBV) infection. EBV‐associated smooth muscle tumors (EBV‐SMT) are considered as a distinct group of smooth muscle tumors with different clinicopathologic features from conventional smooth muscle tumors. A 31‐year‐old female patient presented with a 2‐cm mass at the left labium majus, the clinical diagnosis of which was a Bartholin lesion. She had acquired immunodeficiency syndrome diagnosed 29 months before. Excisional biopsy revealed a cellular tumor composed of round‐ to spindle‐shaped cells with mild to moderate nuclear atypia. The tumor cells were immunoreactive for smooth muscle actin and muscle actin (HHF‐35). Evidence of EBV infection was confirmed by in situ hybridization for EBV‐encoded small RNA‐1. To our knowledge, this is the first case of EBV‐SMT presenting as a vulvar mass. EBV‐SMT should be included in the differential diagnoses of mesenchymal tumor in patients with immunosuppression and in the differential diagnoses of smooth muscle tumor in uncommon sites, including the vulva.