cyclin-d1 and Sex-Cord-Gonadal-Stromal-Tumors

Microcystic stromal tumor (MCST) is a rare subtype of sex cord-stromal neoplasm. Tumors from all 31 previously reported cases were located in the ovary. Herein, we present a unique case of a right-side testicular tumor in a 33-year-old Chinese male. The tumor is composed of predominantly lobulated cellular nodules separated by hyalinized fibrous stroma and they expressed CD10, β-catenin (nuclear), and cyclin D1. Molecular analysis identified a point mutation (c.110C>G) in exon 3 of CTNNB1. The histopathological features, immunohistochemistry profiles, and molecular analysis of this tumor were consistent with MCST of the ovary. Therefore, a diagnosis of MCST of the right testicle was determined. To the best of our knowledge, this is the first case of MCST occurring in the testicles. The study may provide new insights to the tumor biology of MCST and a better understanding of this rare entity.

Topics: Adult; beta Catenin; Cyclin D1; Humans; Male; Neprilysin; Point Mutation; Sex Cord-Gonadal Stromal Tumors; Testicular Neoplasms

Since our first description of the microcystic stromal tumor (MST) of the ovary, a rare and distinctive neoplasm with a definitional, usually striking microcystic pattern and a CD10+/vimentin+/inhibin-/calretinin- immunophenotype, 3 examples with β-catenin nuclear localization, and CTNNB1 mutation have been reported. We undertook a detailed immunohistochemical study and molecular analysis of CTNNB1 and FOXL2 of 15 cases of MST to further characterize this neoplasm and establish its histogenesis. Diffuse nuclear staining for FOXL2, WT-1, cyclin D1, and β-catenin was present in all tumors tested, and 12/15 were positive for steroidogenic factor-1 (SF-1). Heterozygous missense point mutations in exon 3 of CTNNB1 were detected in 8 of 14 cases, resulting in amino acid changes at codons 32, 34, 35, and 37. There was no correlation between CTNNB1 exon 3 mutation status and tumor immunophenotype. All 14 cases tested showed wild-type FOXL2. Our study establishes that MST of the ovary exhibits a characteristic FOXL2/SF-1/WT-1/cyclin D1/nuclear β-catenin-positive immunohistochemical profile, which may be useful in diagnosis and in the exclusion of histologic mimics. The presence of diffuse nuclear FOXL2 and WT-1 immunostaining in all cases and SF-1 in most supports the classification of MST within the sex cord-stromal category. Aberrant nuclear β-catenin expression, detected in all MSTs, appears to be the result of stabilizing CTNNB1 mutations in 57% of cases, providing further evidence that dysregulation of the Wnt/B-catenin pathway is involved in the tumorigenesis of MST and may involve activation of β-catenin with upregulation of cyclin D1.

Topics: Adult; beta Catenin; Biomarkers, Tumor; Cyclin D1; DNA Mutational Analysis; DNA-Binding Proteins; Female; Forkhead Box Protein L2; Forkhead Transcription Factors; Humans; Immunohistochemistry; Middle Aged; Neoplasms, Cystic, Mucinous, and Serous; Ovarian Neoplasms; RNA Splicing Factors; Sex Cord-Gonadal Stromal Tumors; Transcription Factors; Wnt Signaling Pathway; WT1 Proteins