A case of primary peritoneal carcinoma: evidence for a precursor in the fallopian tube.

Background: Primary high-grade serous peritoneal carcinoma (PPSC) is a rare malignancy with an ambiguous pathogenesis.

Case Report: We report on a 51-year-old woman presenting with a routine smear test cytology suspicious of adenocarcinoma. She underwent hysteroscopy, laparsocopy with multiple biopsies and bilateral salpingoophorectomy. She was diagnosed with a serous tubal intraepithelial carcinoma in situ (STIC) in the right fallopian tube. Subsequently, she underwent radical surgery and was diagnosed with peritoneal high-grade serous carcinoma. Interestingly, both ovaries remained histologically tumour-free.

Discussion: High-grade serous carcinomas that arise on the peritoneum with tumour-free ovaries are rare. The findings in this case, coupled with current evidence, strongly suggest a precursor lesion in the fallopian tube (STIC lesions). The clinical implications of this theory reside in the potential for improving early detection strategies. Nonetheless, more data on precursor lesions in the fallopian tubes and their transformation to serous carcinoma are required to plan for future screening methods.