Solitary Fibrous Tumor in the Vulva

Abstract

Solitary fibrous tumor (SFT) is a rare soft tissue tumor that is composed of fibroblastic tumor cells and collagenous stroma with NAB2-STAT 6 gene rearrangement. Vulvar SFTs are extremely rare. We report a case of vulvar SFT and review the current literature. A 71-year-old woman presented with a slow-growing mass in her left labia majora. The patient also complained of urinary stream diversion. Physical examination revealed a tumor in the left labia majora, which manifested as a rubbery, immobile, and tender mass. Computed tomographic images showed an enhanced vulvar mass. Magnetic resonance imaging (MRI) demonstrated a well-defined tumor with heterogeneous intermediate signal intensity on T1-weighted images and heterogeneous high signal intensity on T2-weighted images. The tumor measured 68 × 45 × 57 mm on MRI and was located in the labia majora. Percutaneous needle biopsy revealed an SFT. Immunohisto-chemically, the tumor cells were positive for STAT6 and CD34. Local excision was performed with negative surgical margins. Preoperative needle biopsy was useful for diagnosis and planning a surgical strategy. Local resection of the vulvar SFT improved symptoms of urinary stream diversion. There was no tumor recurrence during the 4 years following the surgery.