A Case of High-Grade Serous Tubal Intraepithelial Carcinoma Diagnosed with Adenocarcinoma by Ascitic Fluid Cytology

Abstract

Fallopian tube cancer is a very rare disease that is difficult to detect in its early stages. To our knowledge, we encountered the first case of serous tubal intraepithelial carcinoma (STIC) diagnosed with adenocarcinoma by ascitic fluid cytology. The patient was a 51-year-old woman who visited our department because of a leiomyoma detected during a uterine cancer screening. Transvaginal ultrasound found multiple leiomyomas and an endometrial cyst of the left ovary. The patients’ cancer antigen 125 level was elevated and the leiomyomas showed a tendency to grow. Therefore, surgical treatment was considered to be appropriate. Preoperative imaging showed no evidence of malignancy. We performed abdominal hysterectomy and bilateral salpingo-oophorectomy. The patient had stage IV endometriosis according to the revised American Society of Reproductive Medicine classification, and no macroscopic abnormalities were found in either fallopian tube. Postoperative histopathological findings led to the diagnosis of STIC in the right fallopian tube; cytological examination of the ascitic fluid also confirmed the presence of adenocarcinoma. We performed a staging laparotomy and found no evidence of metastasis to the lymph nodes or the greater omentum; the staging classification was determined to be IC3. After surgery, six cycles of paclitaxel + carboplatin therapy were administered. The patient has since been relapse-free for 15 months to date. Much attention has been directed to the fallopian tubes as the origin of malignant epithelial ovarian tumors, and STIC is now considered to be the origin of high-grade serous ovarian cancer. To avoid overlooking early-stage fallopian tube cancer, surgery for benign disease should also be accompanied by a detailed histopathological examination of the fallopian tubes.