Endometrial serous carcinoma with a corded and hyalinized pattern: a clinicopathological and molecular analysis.

A corded and hyalinized pattern has been described in endometrial endometrioid carcinoma. Herein, we describe a clinicopathological and molecular analysis of the first reported case of endometrial serous carcinoma with a corded and hyalinized pattern. A 64-year-old woman underwent hysterectomy and bilateral salpingo-oophorectomy due to a 5.5 cm endometrial lesion. Histologically, the tumor was composed of a minor (20%) serous carcinoma component and a predominant corded component embedded in a hyaline-to-myxoid matrix. This component showed diffuse and strong p53 and p16 expression, heterogeneous positivity for epithelial markers and WT1, focal positivity for estrogen and progesterone receptors, retained MMR, SMARCA4/BRG1, and SMARCB1/INI1 expression, and negativity for smooth muscle, germ cell, sex cord, neuroendocrine, endothelial, and melanocytic markers and GATA3. Next-generation sequencing showed a mutation of uncertain significance in APC and no mutations in MLH1, MSH2, MSH6, PMS2, MUTYH, POLE, POLD1, EPCAM, or CTNNB1. The patient had a recurrence on the vaginal stump after 15 months. In conclusion, endometrial serous carcinoma can show a corded and hyalinized pattern, which may represent a diagnostic challenge.