眼睑Merkel细胞癌临床病理分析

Merkel cell carcinoma in eyelid:a clinicopathological analysis

目的:探讨眼睑Merkel细胞癌(Merkel cell carcinoma,MCC)的临床病理特征、诊断与鉴别诊断。方法:观察1例眼睑MCC的组织病理特点和免疫组化染色结果,并复习相关文献。结果:患者男性,78岁。以"发现右眼下睑无痛性结节样包块6月增大1月"入院。基于冷冻切片(Mohs显微外科)评估安全切缘的肿瘤扩大切除术被实施。巨检肿瘤切面呈灰白色,边界清楚。镜下病变主要位于眼睑真皮层,无表皮浸润。肿瘤呈弥漫片层状或巢索状排列,主要由小圆细胞构成,形态单调一致,胞质较少,嗜酸性,核大,圆形或卵圆形,轮廓清晰,细胞呈裸核状,染色质呈空泡状或细颗粒状,核分裂明显。免疫组化显示除了经典神经内分泌抗体如Syn、CgA外,肿瘤细胞还表达CK及CK20(一种关键的MCC诊断标记物),而HMB45、LCA和TTF-1等阴性。结论:Merkel细胞癌是一种罕见的伴有神经内分泌分化的致死性皮肤恶性肿瘤,预后差。需与"小圆蓝细胞肿瘤"成员如恶性淋巴瘤、小细胞无色素性黑色素瘤和转移性肺小细胞癌等鉴别。

Objective：To investigate the clinicopathologic features, diagnosis and differential diagnosis of Merkel cell carcinoma （MCC） of the eyelid. Methods： One case of MCC was analyzed on morphological observation and immunohistochemieal stainings with review of the related literature. Results ： The patient was a 78 - year - old man. He was admitted to the hospital for a painless pink nodule found in his fight lower eyelid. Based on the intraoperative frozen -section （Mohs micrographic surgery） for monitoring of the security margins, a wide excision of the tumor was performed. Grossly, the mass was described as a grayish - white cut surface and an well - defined margin. Microscopically, the neoplasm was infiltrated in layer of the derma of the eyelid without epidermis invoved. The tumor ceils were arranged in a diffuse sheet or nest/cord pattem. And they were consisted predominantly of monotonously uniform, small, round cells which had scant amphophilic cytoplasm and distinct round or oval enlarged nuclei, showing nearly nude nuclei with brisk mitotic activity as well as vacuole and fine granular cytoplasm. Immunohistochemically, besides classic neuroendocrine antibodies, e. g. Syn and CgA, the neoplastic cells were also expressed for CK and CK20 （ as the key diagnostic marker for MCC）. Yet negative for HMB -45, LCA and TTF - 1. Conelusion：MCC is a rare fatal cutaneous malignancy with neuroendocrine differentiation and poor prognosis. It should be distinguished from some ＂ small round blue cell tumor＂ members such as malignant lymphoma, small cell amelanotic melanoma and metastatic small cell lung carcinoma.