Here, we present a case that highlights the crucial pitfalls related to the presence of morular metaplasia (MM) in endometrioid carcinoma, which are insufficiently recognized in the routine pathology practice. A 45-year-old woman underwent hysterectomy with rectosigmoidectomy due to a 11-cm mass involving uterus, right ovary, and rectosigmoid colon. Histologically, the lesion appeared as a predominantly solid carcinoma with a minor glandular component. Results of the first immunohistochemical analysis suggested a colorectal origin (PAX8-, CK7-, WT1-, hormone receptors-, and CDX2+ in the absence of mucinous features). Subsequent immunohistochemistry (nuclear β-catenin+, CD10+, and low ki67 in the solid areas) supported a diagnosis of endometrioid carcinoma with diffuse MM. This case remarks that morphological and immunohistochemical features of MM may conceal the glandular architecture and the typical immunophenotype of endometrioid carcinomas. Acknowledging the diagnostic issues related to MM appears crucial to avoid misdiagnosis and inappropriate patient management.
Pathobiology

中文翻译：

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子宫内膜样癌胞质化生的诊断误区：一个被低估的问题

在这里，我们提出了一个案例，强调了与子宫内膜样癌中存在桑椹化生 (MM) 相关的关键陷阱，这些陷阱在常规病理实践中未被充分认识。一名 45 岁女性因 11 cm 肿块累及子宫、右侧卵巢和直肠乙状结肠而接受了子宫切除术和直肠乙状结肠切除术。组织学上，病变表现为主要为实性癌，伴有少量腺体成分。第一次免疫组织化学分析的结果表明结肠直肠起源（PAX8-、CK7-、WT1-、激素受体-和 CDX2+，没有粘液特征）。随后的免疫组织化学（核β-连环蛋白+、CD10+ 和实性区域的低ki67）支持弥漫性多发性子宫内膜样癌的诊断。该病例说明 MM 的形态学和免疫组织化学特征可能掩盖了子宫内膜样癌的腺体结构和典型的免疫表型。承认与 MM 相关的诊断问题似乎对于避免误诊和不适当的患者管理至关重要。
病理生物学