Brenner
tumors are uncommon
ovarian neoplasms, which have morphologic and immunophenotypical features of transitional cell (urothelial) differentiation. The origin of Brenner
tumors is perplexing, but they are believed to arise from transitional cell
metaplasia occurring within the ovary and/or fallopian tube, although it is controversial whether this
metaplasia is truly along transitional cell lines. Recently, TERT promoter mutations have been identified in urothelial
carcinoma (UC) with high frequency (approximately 70%), and the current literature suggests a potential diagnostic and/or prognostic role of these mutations in UC. Molecular evidence supporting that Brenner
tumors represent
neoplasms exhibiting transitional cell differentiation is scant. To explore this further, we investigated a series of 19 Brenner
tumors of the ovary (15 benign and 4 malignant) for the presence of TERT promoter mutations after genomic
DNA extraction from
formalin-fixed
paraffin-embedded tissue blocks and standard polymerase chain reaction sequencing. TERT promoter mutations were not identified in any of the cases (0/19). The absence of TERT promoter mutations in Brenner
tumors suggests that despite the morphologic and some immunophenotypical resemblance to non-neoplastic and neoplastic transitional epithelium, Brenner
tumors may exhibit a molecularly distinct pathogenesis. The findings also may portend diagnostic utility in rare cases wherein it is difficult to distinguish a primary
malignant Brenner tumor of the ovary from metastatic UC.