Maghsoudlou Sina, Pusztaszeri Marc, Saieg Mauro
Department of Pathology, Jewish General Hospital, McGill University, Montreal, Quebec, Canada.
Diagn Cytopathol. 2025 Jun;53(6):308-311. doi: 10.1002/dc.25472. Epub 2025 Mar 29.
Merkel cell carcinoma (MCC) is a rare and aggressive neuroendocrine skin cancer, often challenging to diagnose due to its morphological resemblance to other malignancies. Diagnosis is typically confirmed by immunohistochemistry (IHC), with most cases being positive for both neuroendocrine and epithelial markers, particularly the characteristic dot-like cytoplasmic pattern seen with Cytokeratin 20 (CK20). This case report describes a 68-year-old male with MCC originating in the left elbow, who developed pleural metastasis 10 months after initial diagnosis and 4 months following a pathologic complete response. IHC analysis confirmed MCC in the pleural fluid with positive markers including: CK20, chromogranin, synaptophysin, MCC polyomavirus, and SATB2, the latter emerging as a valuable adjunct in distinguishing MCC from other neuroendocrine tumors.
默克尔细胞癌（MCC）是一种罕见且侵袭性强的神经内分泌皮肤癌，由于其形态与其他恶性肿瘤相似，诊断往往具有挑战性。诊断通常通过免疫组织化学（IHC）来确认，大多数病例的神经内分泌和上皮标志物均为阳性，特别是细胞角蛋白20（CK20）呈现出特征性的点状胞质模式。本病例报告描述了一名68岁男性，其MCC起源于左肘部，在初始诊断10个月后以及病理完全缓解4个月后发生了胸膜转移。免疫组化分析证实胸腔积液中存在MCC，阳性标志物包括：CK20、嗜铬粒蛋白、突触素、MCC多瘤病毒和SATB2，后者在鉴别MCC与其他神经内分泌肿瘤方面成为一种有价值的辅助手段。
