A 32-year-old woman with a BRCA1 germline mutation undergoes risk-reducing salpingo-oophorectomy. The pathologist performs a SEE-FIM (Sectioning and Extensively Examining the Fimbria) protocol and identifies a microscopic lesion: p53 signature in fimbrial tubal epithelium followed by serous tubal intraepithelial carcinoma (STIC). STIC represents the putative origin of which cancer?
- A Primary peritoneal carcinoma exclusively
- B Clear cell carcinoma of the ovary
- C Low-grade serous carcinoma with KRAS mutations
- D High-grade serous carcinoma of the ovary, fallopian tube, and peritoneum ✓
Explanation
The current evidence strongly supports the distal fallopian tube fimbriae as the origin of high-grade serous carcinoma (HGSC) of the ovary, fallopian tube, and peritoneum — the most common and lethal form of ovarian cancer. The proposed progression is: p53 mutation in tubal secretory cells → p53 signature (secretory cell clusters with p53 mutation) → STIC (serous tubal intraepithelial carcinoma with TP53 mutation, high Ki-67) → invasive HGSC. BRCA1/BRCA2 mutations predispose specifically to this pathway. SEE-FIM protocol maximizes detection of STIC during risk-reducing salpingo-oophorectomy. Low-grade serous carcinomas arise from a different pathway (serous borderline tumors, KRAS/BRAF mutations).
Reference: Robbins & Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.