Sex cord-like endometrioid carcinoma (SCLEC) is an uncommon entity which may constitute a diagnostic challenge. This study aimed to perform a clinicopathological, immunohistochemical, and molecular reappraisal of ovarian SCLEC. Consecutive ovarian SCLECs cases from a single institution were reviewed during a 13-year period. Twenty-three immunohistochemical markers were tested; 10 genes were analyzed by next-generation sequencing. Nine cases of ovarian SCLEC were identified. Mean patient age was 65.7 years; three cases showed extraovarian extension. Architectural pattern included sertoliform (n = 2), granulosa-like (n = 2), and mixed granulosa-like/sertoliform (n = 5). Eosinophilic changes accompanied by increased nuclear atypia were observed in four tumors. Endometrioid features (glands, squamous/morular differentiation) were observed in six cases. Most tumors were positive for cytokeratin-7 (8/9), EMA (9/9), estrogen and progesterone receptor (9/9), CD10 (7/9, including a luminal pattern reminiscent of mesonephric neoplasms), nuclear β-catenin (8/9), and CDX2 (8/9). A minority of cases showed block-type p16 pattern (2/9), PAX8-positivity (3/9), and non-diffuse positivity for WT1 (1/9), inhibin (1/9), chromogranin (1/9), and synaptophysin (2/9). All cases were negative for GATA3, TTF1, calretinin, and SF1. Ki67 range was 15–90%. Six cases showed CTNNB1 exon 3 mutation. Eight cases were of “no specific molecular profile” (NSMP) and one was p53-abnormal. In conclusion, SCLECs frequently exhibit a mixed sertoliform/granulosa-like architecture and express epithelial markers, hormone receptors, nuclear β-catenin, and CDX2, with luminal CD10 positivity and CTNNB1 mutations. PAX8 expression is often lost, while other mesonephric, sex cord, and neuroendocrine markers are negative.

性索样子宫内膜样癌（SCLEC）是一种罕见的实体，可能构成诊断挑战。本研究旨在对卵巢 SCLEC 进行临床病理学、免疫组织化学和分子重新评估。对来自单一机构的 13 年期间的连续卵巢 SCLEC 病例进行了审查。测试了二十三个免疫组织化学标记物；通过下一代测序分析了 10 个基因。确定了 9 例卵巢 SCLEC。患者平均年龄为 65.7 岁；3例显示卵巢外扩展。结构模式包括螺旋状 ( n  = 2)、颗粒状 ( n  = 2) 和混合颗粒状/螺旋状 ( n  = 5)。在四个肿瘤中观察到嗜酸性粒细胞变化伴随着核异型性增加。在六例病例中观察到子宫内膜样特征（腺体、鳞状/胚状分化）。大多数肿瘤呈细胞角蛋白-7 (8/9)、EMA (9/9)、雌激素和孕激素受体 (9/9)、CD10（7/9，包括让人想起中肾肿瘤的管腔模式）、核 β- 阳性。连环蛋白 (8/9) 和 CDX2 (8/9)。少数病例显示块型 p16 模式 (2/9)、PAX8 阳性 (3/9) 以及 WT1 (1/9)、抑制素 (1/9)、嗜铬粒蛋白 (1/9) 非弥漫性阳性）和突触素（2/9）。所有病例的 GATA3、TTF1、钙视网膜蛋白和 SF1 均为阴性。Ki67 范围为 15–90%。6例显示CTNNB1外显子3突变。8 例为“无特定分子谱”(NSMP)，1 例为 p53 异常。总之，SCLEC 经常表现出混合的锯齿状/颗粒状结构，并表达上皮标记物、激素受体、核 β-连环蛋白和 CDX2，具有管腔 CD10 阳性和CTNNB1突变。PAX8 表达经常丢失，而其他中肾、性索和神经内分泌标记物呈阴性。