骨盆與會陰部侵襲性黏液瘤之罕見病例報告

康庭碩、黃勝賢

彰化基督教醫院 外科部 泌尿科

Pelvic and Perineal Aggressive Angiomyxoma: A Rare Case Report

Ting-Shuo Kang, Sheng-Hsien Huang

Divisions of Urology, Department of Surgery, Changhua Christian Hospital

Introduction:

Aggressive angiomyxoma (AAM) is a rare, slow-growing mesenchymal tumor that primarily involves the pelvis and perineum of women of reproductive age. It is characterized by local infiltration, a high recurrence rate (30–72%), and rare distant metastasis. Clinically, it often presents as a painless vulvoperineal mass and may be mistaken for other benign soft tissue lesions. Definitive diagnosis relies on histopathology showing spindle cells in a myxoid stroma with prominent vascularity. Surgical excision with clear margins remains the cornerstone of treatment, though long-term surveillance is required. We present a case of a 31-year-old woman with a large, infiltrative pelvic AAM successfully managed with preoperative embolization and a multidisciplinary surgical approach.

Case presentation:

A 31-year-old woman presented with a five-year history of a progressively enlarging, painless right labial mass that had recently grown rapidly. She had no significant medical or surgical history. Examination revealed a 15 cm, soft, non-tender vulvar mass. Serum tumor markers were within normal limits. Pelvic MRI showed an infiltrative, enhancing lesion extending from the right pelvis into the labia majora. Preoperative transarterial embolization of feeding branches from the right internal iliac artery was performed, followed by laparoscopic transperitoneal excision of the retroperitoneal tumor with labial reconstruction. The resected mass measured 18 × 15 × 4.5 cm. Histopathology revealed an unencapsulated tumor composed of bland spindle cells in a myxoid stroma with prominent vessels and entrapped adipose tissue. Immunohistochemistry was negative for MDM2, CDK4, S-100, desmin, SMA, CD34, HMB-45, melan-A, and β-catenin, confirming aggressive angiomyxoma. The patient recovered uneventfully and was advised on the high risk of local recurrence and the importance of long-term follow-up.