Corded and hyalinized endometrioid carcinoma: Summary of clinical, histological, immunohistochemical and molecular data

Corded and hyalinized endometrioid carcinoma (CHEC) represents a potential pitfall for pathologists. This study aimed to provide a complete overview of all clinicopathological and molecular features of CHEC. Electronic databases were searched for all published series of CHEC. Clinical, histological, immunohistochemical and molecular data about CHEC were extracted and pooled. Six studies with 62 patients were identified; mean age was 49.8 years (range 19-83). Most cases showed FIGO stage I (68%), low grade (87.5%), and a favorable outcome (78.4%), with "no specific molecular profile" (NSMP). A subset of cases showed high-grade features (12.5%), p53 abnormalities (11.1%) or mismatch repair (MMR) deficiency (20%) and occurred at an older age (mean age>60 years). Common features of CHEC were: superficial localization of the corded component (88.6%), squamous/morular differentiation (82.5%), nuclear β-catenin accumulation (92%), partial/total loss of CKAE1/AE3 (88.9%), estrogen receptor (95.7%) and e-cadherin (100%), stromal changes such as myxoid (38.5%), osteoid (24%) and chondroid (4.5%), CTNNB1 mutations (57.9%), and POLE-wild-type (100%); 24.4% of cases showed lymphovascular space invasion. A minority of cases (16.2%) showed poor outcome despite a low-grade, NSMP phenotype; the molecular basis for the aggressiveness of these cases is still undefined. Further studies are necessary in this field.

Corded and hyalinized endometrioid endometrial carcinoma with high-grade features: a clinicopathological and TCGA-based molecular analysis

Corded and hyalinized endometrioid carcinoma (CHEC) typically shows low-grade features and "no specific molecular profile" (NSMP). This study aimed to perform a clinicopathological and molecular characterization of endometrial CHEC with high-grade features. Immunohistochemistry for cytokeratin AE1/AE3, e-cadherin, β-catenin, estrogen receptor, progesterone receptor, p53, p16, and mismatch repair proteins was performed. A next-generation sequencing kit was used to assess POLE, POLD1, APC, MLH1, MSH2, MSH6, PMS2, MUTYH, EPCAM, and CTNNB1. Molecular groups, i.e., POLE-mutant, mismatch repair deficient (MMRd), p53-abnormal, and NSMP, were assigned according to the TCGA classifier. Six high-grade endometrial CHECs were identified. The mean age was 57.5 years; 5/6 cases were uterine-confined. Five cases showed a diffusely and markedly atypical corded component and a MMRd or p53-abnormal signature; additional features included single-cell keratinization, necrosis, osteoid or myxoid/chondro-myxoid matrix, foci of anaplasia, and nuclear β-catenin expression. The remaining case showed a low mitotic count and a NSMP phenotype, with focal bizarre cells in an otherwise classical CH endometrioid carcinoma. All cases showed variably reduced expression of epithelial markers and hormone receptors in the corded component. No mutations were found in any of the analyzed genes. In conclusion, high-grade CHECs are a heterogeneous subset of biphasic endometrial carcinoma which show similarities and differences with classical CHEC and carcinosarcoma. These cases often show MMRd or p53-abnormal signatures.

Corded and hyalinized mesonephric-like adenocarcinoma of the uterine corpus: report of a case mimicking endometrioid carcinoma

Mesonephric-like adenocarcinoma is a recently described adenocarcinoma of the uterine body and ovary with overlapping features of mesonephric adenocarcinoma and endometrioid carcinoma. It is thought to be a mullerian adenocarcinoma that has differentiated along mesonephric lines. A 71-year-old woman had a 3-cm endometrial mass that invaded the myometrium without gross or microscopic evidence of cervical involvement. The tumor had a variety of architectural patterns and produced prominent stromal hyalinization containing embedded cords and trabeculae of tumor cells. No squamous or mucinous differentiation or associated mesonephric remnants or hyperplasia was identified. The tumor was positive for TTF1 and GATA3, very focally and weakly positive for estrogen receptor and negative for progesterone receptor and nuclear expression of β-catenin. An unusual inverse pattern of TTF1 and GATA3 immunoreactivity was observed. DNA analysis by digital droplet polymerase chain reaction and quantitative polymerase chain reaction identified an activating KRAS (G12A) mutation. The tumor was interpreted as corded and hyalinized mesonephric-like adenocarcinoma that mimicked corded and hyalinized endometrioid carcinoma.