Pilomatrix-like High-grade Endometrial Carcinoma

作者：Feng Zhou, Lei Qin, Suming Huang, Wanrun Lin, Huijuan Zhang, Vinita Parkash, Wenxin Zheng · 发表于：The American Journal of Surgical Pathology · 年份：2025 · DOI：10.1097/pas.0000000000002402 · 被引用次数：10 · 研究领域：Cancer and Skin Lesions、Cancer Diagnosis and Treatment、Hedgehog Signaling Pathway Studies

Pilomatrix-like high-grade endometrial carcinoma (PiMHEC) is a rare and aggressive variant of endometrial carcinoma often misdiagnosed due to overlapping features with other high-grade malignancies. This study characterizes its clinicopathologic, immunophenotypic, and molecular features to establish key diagnostic criteria and propose a standardized terminology. Ten tumors were analyzed using histopathologic examination, immunohistochemistry, and next-generation sequencing. All but 1 tumor exhibited both low-grade endometrioid and high-grade basaloid components, the latter characterized by either geographic or comedo-type necrosis and shadow cells. Although shadow cells are a hallmark feature, they may be focal or absent, necessitating careful evaluation. High-grade areas consistently showed ER and PR negativity with diffuse nuclear β-catenin staining, correlating with CTNNB1 exon 3 mutations in all tumors. Identical CTNNB1 mutations in spatially distinct tumor components suggest a clonal progression from a low-grade precursor. Additional mutations in ARID1A, PTEN, and PIK3CA were identified. Clinically, PiMHEC exhibited aggressive behavior, with 7 patients experiencing recurrence and 1 succumbing to the disease within 9 months. Metastatic sites included the lungs, liver, lymph nodes, and abdominal wall. PD-L1 expression in 4 tumors suggests potential responsiveness to immune checkpoint inhibitors, whereas low-level HER2 expression (1+ to 2+) in 5 tumors raises the possibilit...