ESR1 and endometrioid adenocarcinoma: Morphologically, both MLA and MNAC could reveal different growth patterns including retiform, papillary, tubular, sex cord, glandular, glomeruloid, spindled, sieve-like, and solid architectures in various combinations, even in the same neoplasms.[2,7,9] MLAs lack mucinous and squamous differentiation and may also show morphology reminiscent of the corded and hyalinized variant of endometrioid carcinoma.[6,9] Immunohistochemically, MLAs frequently exhibit positive staining for calretinin, GATA-3, and CD10 (luminal staining), and almost all of them are positive for TTF-1 and negative for PR/ER.