Serous Tubal Intraepithelial Carcinoma (STIC/TIC)

Tubal carcinoma in situ

High-grade tubal intraepithelial neoplasia

Epidemiology:

• Most common malignancy found in risk-reducing salpingo-oophorectomies from women with germ-line BRCA1 or BRCA2 mutations
• 5-10% of asymptomatic BRCA mutation carriers by SEE-FIM protocol
• Exceedingly rare in women who do not have a BRCA mutation or a comcomitant high-grade serous cancer
• Earliest known manifestation of most pelvic serous cancers

Common sites:

• Distal tube (virtually all – 90%)

Gross features:

• Not grossly identifiable unless associated early carcinoma

Histologic features:

• Nuclear atypia
• marked nuclear pleomorphism
• prominent nucleoli
• note that nuclear crowding and atypia alone is not enough
• increased n:c ratio, loss of polarity
• lack of cellular cohesion
• epithelial cells forming papillae
• cytologically malignant cells
• mitotically active

Immunophenotype:

Marker:	Sensitivity:	Specificity:
p53 (strong diffuse usually) (complete absence sometimes)
Ki-67 (>= 15%; may exceed 50%)

Molecular features:

• TP53 mutation (92%)

Other features:

• Low risk of metastatic disease following excision (~5-10%) for localized non-invasive STIC