Diffuse uterine leiomyomatosis with a mesenteric smooth muscle lesion and a reported family history of uterine leiomyomas: a case report and literature review

Abstract Background Diffuse uterine leiomyomatosis (DUL) is a rare benign smooth muscle disorder characterized by diffuse proliferation of innumerable, poorly circumscribed leiomyomatous nodules throughout the myometrium. Because its clinical and radiologic features overlap with those of multiple conventional uterine leiomyomas, DUL is frequently difficult to diagnose before surgery. Coexisting extrauterine smooth muscle lesions are exceptionally uncommon, and the potential contribution of familial susceptibility to uterine smooth muscle proliferation remains poorly understood. Case presentation We report a 34-year-old woman who presented with progressive menorrhagia and dysmenorrhea and was initially diagnosed with multiple uterine fibroids. She reported a maternal family history of uterine leiomyomas. Myomectomy revealed diffuse, ill-defined nodular smooth muscle proliferation throughout the myometrium, consistent with DUL. Twenty-two months later, recurrent uterine disease required further surgery, aduring which a solitary mesenteric nodule was identified. The patient underwent total hysterectomy and resection of the mesenteric lesion. Histopathological examination confirmed recurrent DUL and a benign mesenteric smooth muscle lesion that was morphologically similar to the uterine lesions. Whole-exome sequencing of the available uterine tumor tissue and blood samples identified candidate variants. A focused review of previously reported cases showed that extrauterine smooth muscle lesions in patients with DUL are rare and that the biological significance of the reported family history remains uncertain. Conclusion This case illustrates that recurrent DUL can coexist with a histologically benign mesenteric smooth muscle lesion and a reported family history of uterine leiomyomas. It highlights the value of integrated clinicopathological assessment and longitudinal follow-up when unusual extrauterine smooth muscle lesions are encountered in patients with DUL.