Benign Vulval Leiomyoma: Report of a Rare Case.

A vulval leiomyoma is an uncommon, benign mass often misdiagnosed as a Bartholin cyst. Its precise etiology is currently unknown, though it typically arises from the deep connective tissue within the labia majora. Clinically, it presents as a slowly developing perineal mass, with pain and distress being the primary symptoms. We present the case of a 41-year-old woman with a one-year history of a gradually expanding vaginal mass. Examination revealed a left-sided vulval mass over 6 cm. Surgical excision was performed, and intraoperatively, an additional 7 cm mass extending deep into the perineum was found on the right vulva, confirming leiomyoma rather than a Bartholin's cyst. Histopathological examination confirmed a smooth muscle tumor with myxoid stroma, no atypia or necrosis, and postoperative MRI showed multifocal confluent soft tissue nodules in the perineum. Differentiation from a Bartholin cyst can be challenging due to similar presenting symptoms, including erythema, irritation, localized enlargement, and an asymptomatic mass. However, specific physical findings, such as inverted labia minora and a firm consistency of the swelling, can support a diagnosis of vulvar leiomyoma, contrasting with the everted labia minora and cystic structure seen in Bartholin cysts. Histopathological examination and MRI findings are crucial for accurate diagnosis and for distinguishing between benign and malignant forms. Surgical excision is the definitive treatment for benign vulval leiomyomas.