Hepatic uterus-like mass misdiagnosed as hepatic abscess

Background. Hepatic endometriosis/uterus-like mass is rare and may be overlooked during hepatic cyst workups. We report a case of uterus-like mass, misdiagnosed as hepatic abscess. Case Report: A 47-year-old woman developed abdominal pain and vomiting. Infectious colitis with hepatic abscess was diagnosed, and remained antibiotic-refractory. Fine-needle aspiration and core biopsies showed benign contents. The patient presented to our institution with symptoms and normal blood work. Laparoscopic excision demonstrated a 1.4-cm cyst composed of endometrial glands (estrogen receptor+ and progesterone receptor+) and stroma (CD10+) with smooth muscle actin (SMA+), arranged in an organoid fashion. The patient, status-post hysterectomy, had no history or symptoms of endometriosis. Conclusion. This rare case illustrates the merit of considering uterus-like mass/endometriosis in the differential diagnosis of antibiotic-refractory hepatic cysts. Cyst heterogeneity may confound needle biopsy. We report the first instance of a hepatic uterus-like mass, with a review of related entities, postulated histogenesis, and important clinical associations.