High-grade corded and hyalinized endometrioid carcinoma of "no specific molecular profile": report of two cases.

High-grade corded and hyalinized endometrioid carcinoma (CHEC) is an uncommon endometrial carcinoma variant which may mimic carcinosarcoma or dedifferentiated carcinoma and has shown association with mismatch repair deficiency (MMRd) and p53 abnormalities. Herein, we expand the spectrum of high-grade CHEC by presenting two cases showing a "no specific molecular profile" (NSMP). Case #1 was a 6-cm endometrial mass in a 25-year-old woman, infiltrating the deep myometrium and cervical stroma, with diffuse lymphovascular space invasion. Case #2 was an advanced, unresectable endometrial carcinoma involving the lower third of the vagina in an 81-year-old woman. On the endometrial biopsy specimen, both cases showed a markedly atypical and mitotically active corded component merging with a FIGO G3 endometrioid component and accompanied by squamous/morular differentiation. Both tumors showed nuclear β-catenin accumulation, retained MMR protein expression, wild-type p53 pattern, and no POLE mutations. The corded component was absent in the hysterectomy specimen of case #1 and in the vaginal biopsy specimen of case #2. The present cases confirm the clinical and molecular heterogeneity of high-grade CHEC, including a wide age range at presentation, variable prognosis, and variable molecular background. Nonetheless, these cases retain unique features that support their distinction from carcinosarcoma and dedifferentiated carcinoma. We suggest to consider them as a variant of FIGO G3 endometrioid carcinoma. Further studies are necessary in this field.