A rare case of invasive mucinous adenocarcinoma of fallopian tube fimbria with metastasis to ipsilateral ovary, uterine serosa, myometrium and pelvis: Case report and review of literature

Mucinous adenocarcinoma of the fallopian tube is exceptionally rare and the detailed clinicopathologic features of these tumors have not yet been reported in English literature. Here we report a moderately differentiated mucinous adenocarcinoma arising in the tubal fimbria in a 70-year-old woman. Patient had a history of cholecystectomy for gallstones and gastric banding who presented with gastrointestinal discomfort and was found to have a large adnexal mass on imaging studies. Serum CA-125 was moderately elevated. Recent mammography, upper endoscopy and colonoscopy were completely normal. She underwent surgical staging for the adnexal mass. Frozen section and final pathology diagnosis revealed moderately differentiated adenocarcinoma arising in the left fimbria. Carcinoma had spread to the ipsilateral ovary and pelvic soft tissue at the time of her presentation. Tumor was strongly immunoreactive to CK7 and CEA, and was negative for CK20, CDX-2, PAX-8, WT-1, p16, ER, and vimentin. TP53 showed wild-type phenotype by immunohistochemistry. Molecular studies showed no mutation in codon 12 and 13 of the k-ras gene, and no mutation was detected in the BRAF and EGFR genes. In addition, the non-tumorous fimbria epithelium showed a spectrum of mucinous alterations with variable nuclear atypia: cytologically bland areas that were reminiscent of mucinous metaplasia were positive for p53 and showed minimal proliferation as assessed by Ki-67, and cytologically atypical stratified mucinous epithelium that was positive for p53 and Ki-67. The patient received 3 cycles of Folfox and was regularly followed at a 3–6 month interval. Her carcinoma recurred in abdomen at 32 months post surgery. After excluding the possibility of an extra-gynecologic tract primary through extensive clinical investigations and post-surgical follow-up, we concluded that this tumor most likely represented a mucinous adenocarcinoma of tubal origin.