Extrauterine adenomyoma of the liver: A case report with a review of the literature.

Extrauterine adenomyoma is an exceedingly rare benign lesion composed of endometrial glands/stroma embedded within smooth muscle bundles and located outside the uterus. The majority of extrauterine adenomyomas occur in the pelvis involving the ovary, rectovaginal space, or broad ligament; hepatic involvement is extremely rare. We present the case of a 47-year-old woman with a subcapsular mass in segment VI of the liver that was detected during the work-up for abdominal pain. Initial core needle biopsy of the mass was suggestive of FNH or hepatic adenoma, with expert consultation favoring parasitic leiomyoma. Finally, the patient underwent surgical resection, and the histopathological exam revealed endometrial glands and stroma, admixed with smooth muscle, confirming the diagnosis of extrauterine adenomyoma. This case highlights the diagnostic challenge of extrauterine adenomyoma and emphasizes the importance of considering this entity in the differential diagnosis of pelvic or extrapelvic masses, particularly in women with a history of gynecologic lesions. Recognizing this rare condition may help prevent misdiagnosis and inappropriate management.