Leiomyomatosis: A Rare Case of Mistaken Identity

Abstract: Diffuse uterine leiomyomatosis (DUL) is a rare benign uterine pathology that is often misdiagnosed as uterine leiomyomas. We present a case of a woman with abnormal uterine bleeding treated with multiple medical therapies without symptomatic relief. She underwent two surgeries, almost a year apart, with the histopathologic diagnosis of leiomyomas. After numerous failed attempts at medical and surgical treatments, the patient requested definitive surgery and underwent a robotic-assisted laparoscopic hysterectomy. Histopathologic analysis of the entire uterine specimen confirmed diffuse uterine leiomyomatosis. Case Report: A 31-year-old female was referred to our office with a history of abnormal uterine bleeding and heavy menstrual bleeding who failed hormonal therapies. Levonorgestrel-releasing intrauterine devices were inserted at two different times and were expelled due to heavy menses. Pelvic magnetic resonance imaging reported leiomyomas. The patient underwent hysteroscopy and a robotic-assisted myomectomy. Pathology revealed leiomyomas. Seven months after her first surgery, her bleeding recurred, and the patient became severely anemic, requiring hospitalization and transfusion of 2 units of packed RBCs. Over a year later, the patient underwent a second hysteroscopic and robotic myomectomy after failed medical therapies of tranexamic acid, progesterone medication, and gonadotropin-releasing hormone antagonist with minimal symptom relief. Her quality of life suffered tremendously due to ongoing AUB-HMB. After seven months, the patient requested definitive surgical therapy and underwent a robotic-assisted laparoscopic hysterectomy. Pathology reported diffuse uterine leiomyomatosis. Diffuse uterine leiomyomatosis is a rare benign uterine pathology that is often misdiagnosed as uterine leiomyomas. Early diagnosis of DUL is challenging and often inconclusive. Less than 50 diffuse uterine leiomyomatosis cases have been reported in the literature. The myometrium in DUL is almost entirely replaced by numerous ill-defined benign smooth muscle tumors. MRI offers mapping of the size, site, and distribution of leiomyomas, but findings are difficult to differentiate from DUL. The pathophysiology of DUL development remains poorly understood, with patients frequently complaining of abnormal uterine bleeding, heavy menstrual bleeding, fertility issues, and dysmenorrhea. DUL is often misdiagnosed as leiomyomas or adenomyosis clinically, given the similarity in manifestations. Leiomyomatosis is histologically characterized by the proliferation of smooth muscle cells forming fascicles and nodules, which blend with normal myometrium tissue. Hysterectomy is the definitive treatment of DUL, with this case report demonstrating the close similarity between the two.