Tubal Tumor Morphology

Fallopian tube epithelial primaries include serous tubal intraepithelial carcinoma (STIC), invasive mucosal carcinoma, low-grade serous carcinoma, high-grade serous carcinoma, endometrioid carcinoma, mucinous carcinoma, transitional cell carcinoma, and clear cell carcinoma. Here, we focus on STIC, a newer entity.

Serous Tubal Intraepithelial Carcinoma (STIC):

• Originates in the fallopian tube (C570)
• ICD-O Histology code: 8441/2
• In situ neoplasm
• Initially discovered in salpingectomy specimens from women who underwent a bilateral salpingectomy-oophorectomy because of BRCA1 & BRCA2 mutations
• Can spread to abdominal cavity [this spread does not indicate an invasive (/3) behavior]
• Potential precursor to high grade serous carcinomas (HGSC)
• Staged as International Federation of Gynecology & Obstetrics (FIGO) IA
  • The only primary site is fallopian tube with STIC present

  -and-

  • Staging and peritoneal washing are both negative
• Increased Ki-67 proliferation index
• Harbor TP53 mutations leading to aberrant expression on immunohistochemistry (IHC)
  • Nuclear overexpression

  -or-

  • Complete lack of p53 expression
• Differential diagnosis: metastatic carcinoma from an extra-tubal primary

Updated: June 8, 2018