An Incidental Fallopian Tube Focal Serous Tubal Intraepithelial Lesion (STIL) Discovered on a Postoperative Pathology Report Following Hysterectomy and Salpingectomy: A Case Report

A focal serous tubal intraepithelial lesion (STIL) is a rare lesion found on fallopian tubes that are characterized by atypical epithelial cells exhibiting morphological abnormalities with the accumulation of mutant p53 proteins. The p53 gene is a tumor suppressor gene, and when mutated gives rise to mutant p53 proteins that promote cancer cell growth and survival. We present a case of a 47-year-old gravida 2, para 2002 (G2P2) female who presented to the outpatient clinic with bilateral lower quadrant abdominal pain and back pain of four years' duration. The patient's history included endometriosis with lysis of adhesions and gynecological laparoscopy, leiomyomata, infertility, ovarian cyst, dysmenorrhea, two full term births, and Essure implants used for contraception; her family history included maternal grandfather with breast cancer. Multiple fibroids and endometriosis were confirmed on pelvic ultrasound (US) and magnetic resonance imaging (MRI). Due to worsening pain, the patient chose to have an elective hysterectomy and Essure implant removal with bilateral salpingectomy. The postoperative pathology report revealed a right fallopian tube with a STIL. Multiple genetic mutations are known to contribute to the development of STILs including p53 and the breast cancer gene (BRCA). There are two BRCA genes, BRCA1 and BRCA2, that have many functions including producing proteins that repair damaged DNA. When mutated, this allows cells to divide and change rapidly, leading to certain types of cancer. Given the patient's family history of breast cancer, the patient was tested for BRCA1 and BRCA2 for which the results were negative. However, even without having a BRCA mutation that is known to increase the risk of ovarian, fallopian tube, and peritoneal cancers, STILs continue to pose an increased risk of high-grade serous ovarian carcinoma (HGSOC). This case demonstrates the reasoning behind prophylactic salpingectomies alongside hysterectomies and the significance of the postoperative pathology report from gynecological procedures.