Extrauterine myxoid leiomyoma mimicking an aggressive angiomyxoma

Abstract

Introduction: Leiomyomas are benign smooth muscle tumours that usually arise from the uterus. Extrauterine leiomyomas are rare. We present a case of an extrauterine myxoid leiomyoma in a perimenopausal woman. Case: A 47-year-old woman presented with an increase in abdominal girth. Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) scans revealed a large, lobulated, complex mass occupying the lower abdomen and pelvis with extension to the left ischiorectal fossa. An aggressive angiomyxoma (AAM) was considered as one of the differentials for this mass. Multiple attempts at radiological guided biopsy were performed, but with non-diagnostic yield. Intraoperatively, the mass encased the sigmoid colon, rectum, vaginal wall, and was adherent to bilateral pelvic sidewalls, pelvic floor, and left ischiorectal fossa. Enbloc resection of the mass, including an abdominoperineal resection and a total abdominal hysterectomy bilateral salpingo-oophrectomy (TAHBSO) was performed. Final histology showed features consistent with myxoid leiomyoma (ML). Conclusion: The radiological and pathological resemblance of ML and AAM presents a great diagnostic challenge. However, the actual diagnosis lies in the pathological analysis. Surgical resection with clear margins is the treatment of choice in the absence of a definite diagnosis. Prognosis of these tumours is generally good with low recurrence rates.