Uterine carcinoma of the lower uterine segment (LUS) is a rare tumor that accounts for 3-3.5% of cases of uterine malignant cancer. The tumor arises from the lower region of the uterine body through the upper region of the cervix. The present study reported a case of clear cell carcinoma that originated from the LUS. A 50-year-old woman visited a local hospital due to irregular vaginal bleeding. She was suspected to have a uterine tumor and was referred to Tachikawa Hospital (Tokyo, Japan). Transvaginal ultrasound and magnetic resonance imaging revealed a uterine tumor from the lower region of the uterine body through the upper region of the cervix. Endocervical curettage revealed clear cell carcinoma. Based on a diagnosis of clear cell carcinoma of the LUS, radical hysterectomy was performed with bilateral salpingo-oophorectomy, paraaortic lymph node dissection and omentectomy. Macroscopically, the tumor was limited to the lower region of the uterine body through the upper region of the cervix in the resected uterus. Histopathological findings indicated no tumors in the uterine corpus and uterine cervix, but clear cell carcinoma was observed in the LUS epithelium. At the 1-year follow-up, the patient remained free of local recurrence and metastasis. To the best of our knowledge, clear cell carcinoma of the LUS has not previously been reported. More cases are required to clarify the pathology.
Keywords: Lynch syndrome; clear cell carcinoma; endometrial carcinoma; isthmus; lower uterine segment.