A case of undifferentiated carcinoma arising from adenomyosis

Malignant transformation of adenomyosis is rare, with endometrioid carcinoma being the most common histological type. Herein, we report the first extremely aggressive case of undifferentiated carcinoma arising from adenomyosis. A 59-year-old Japanese woman was referred to our hospital with complaints of general fatigue, abdominal fullness, and loss of appetite. Contrast-enhanced computed tomography (CT) and integrated whole-body positron emission tomography/CT using ¹⁸F-fluorodeoxyglucose revealed multiple para-aortic and pelvic lymph node swellings. Contrast-enhanced magnetic resonance imaging revealed a 3-cm degenerated intramural uterine tumor. The patient underwent total hysterectomy, bilateral salpingo-oophorectomy, para-aortic and pelvic lymphadenectomy, and partial omentectomy for the treatment. Pathologically, the patient was diagnosed with undifferentiated carcinoma arising from adenomyosis. Despite adjuvant chemotherapy, the patient died of the disease 7 months after the initial surgery. Further investigation of similar cases may reveal the clinical features of this disease.