β-catenin (CTNNB1) S33C Mutation in Ovarian Microcystic Stromal Tumors

• DOI: 10.1097/pas.0b013e31822d6c71
• Publication Date: 2011-10-04T22:26:17Z
• Authors: Daichi Maeda; Junji Shibahara; Takahiko Sakuma; Masanori Isobe; Shinichi Teshima; Masaya Mori; Katsutoshi Oda; Shunsuke Nakagawa; Yuji Taketani; Shumpei Ishikawa; Masashi Fukayama
• Keywords: Ovarian tumor; Histogenesis; Immunophenotyping

Microcystic stromal tumor (MCST) is a recently described subtype of ovarian characterized by prominent microcystic histologic pattern and diffuse immunoreactivity for CD10 vimentin. However, its pathobiology, particularly histogenesis, remains largely unclear. Here, we report 2 cases MCST, in which have performed extensive histologic, immunohistochemical, genetic investigations to determine distinct nature among neoplasms. The patients were 32 41 years age. Both tumors solid cystic masses involving the right ovary. Microscopically, cells with generally bland, round-to-ovoid nuclei grew microcystic, macrocystic, patterns. Intervening thick fibrous stroma was observed. Immunohistochemically, diffusely strongly positive CD10, vimentin, Wilms 1. Furthermore, detected aberrant nuclear expression β-catenin protein both cases. Of interest, mutation analyses revealed presence an identical point mutation, c.98C>G, exon 3 (CTNNB1) tumors. This oncogenic that causes replacement serine cysteine at codon 33, leading loss phosphorylation site protein. results this study suggest dysregulation Wnt/β-catenin pathway plays fundamental role pathogenesis MCST. Finally, comparing immunophenotype MCST mimics other sex cord-stromal tumors, able identify unique features panel markers useful differential diagnosis.