Aberrant nuclear beta-catenin expression in the spindle or corded cells in so-called corded and hyalinized endometrioid carcinomas. Another critical role of the unique morphological feature.

Abstract

Corded and hyalinized endometrioid carcinoma (CHEC), showing spindle and/or corded (SPICO) cells often in the background of hyalinized stroma, is a rare variant of uterine endometrioid carcinomas. The aim of our study was to explore the status of cell-adhesion molecules (beta-catenin, E-cadherin) in CHECs and to survey whether immunostains for beta-catenin and p53 can help to distinguish CHECs from their morphological mimics: malignant mixed mullerian tumors (MMMTs) and uterine tumors resembling ovarian sex-cord tumors (UTROSCTs). Immunohistochemistry was performed and scored for each element as follows: 0: negative, 1+: <10% positive cells, 2+: 10-30%, 3+: >30%. The SPICO patterns were classified as spindle/fusiform; 3, corded; 1, and both; 2. SPICO components consisted of <10%: 4, 10-30%: 1, >30%: 1. Five contained squamous components. In SPICO elements of all CHECs, nuclear beta-catenin expression (score: 1+; 1, 2+; 2, 3+; 3) and complete loss of membranous expression of E-cadherin was observed. In contrast, comparable components (sarcomatous ones for eight MMMTs or sex-cord-like ones for six UTROSCTs) showed no nuclear positivity for beta-catenin. p53 expression was observed in SPICO (64.7%), sarcomatous (87.5%), and sex-cord-like (50%) components, and sarcomatous areas of most MMMTs notably showed diffuse and intense staining. Sequence analysis of PCR amplification products of exon 3 of the beta-catenin gene revealed mutation in all cases, except two lacking SPICO components represented on microdissected areas. Our results suggest that alterations in beta-catenin/E-cadherin complex play a critical role in SPICO features. Immunostain for beta-catenin and p53 is a promising approach for distinguishing CHECs from MMMTs and UTROSCTs.