Merkel细胞瘤的影像特征及其病理基础

目的探讨Merkel细胞瘤的影像学诊断方法。方法对一例女性，44岁。通过CT、MRI、病理、手术观察其影像及病理特征。结果病理见：红褐色肿物，呈烂肉样，质中，易于吸除，血运丰富。枕骨破坏，枕部肌肉、硬膜表面及小脑内均有肿瘤侵润，与脑组织无明显界限。光镜：肿瘤位于真皮，有时在皮下。癌细胞聚集分布，细胞大小一致，类圆形，似小淋巴细胞；细胞核呈空泡状，可见许多核分裂像，染色质呈细颗粒状；胞浆稀少，嗜酸染色。免疫组化：NSE(神经内分泌颗粒)：阳性。角蛋白：阳性。CT见略高密度均匀的病变，MRI上T1w、T2w呈略低信号，边界不清；MRI可见病变异常强化，边界清晰；局部软组织侵润及骨破坏。结论CT和MRI可以清楚显示病变部位特点，为临床提供可靠信息，利于手术。

The Imaging Feature of Merkel Cell Carcinoma and Its Pathologic Basis

Objective To explore the imaging diagnostic method of Merkel cell carcinoma(MCC). Methods Imaging and pathologic features of MCC of 1 female and 44 years old patient were determinded by CT, MRI, pathologic examination and operative observation. Results MCC is a rare subepidermal carcinoma, and most located in the head, neck region and extrimities. Clinically, only a presumptive diagnosis of MCC can be established. The definite diagnosis of MCC can be made only by pathologic examination, especially immunohistological method. MCC is red and brown, and looks like rotten meat. MCC texture is middle with rich blood supply. MCC can invade occipital bone, occipital muscles, dura and cerebellar tissues. Optical microscope observation showed that MCC is located at dermis, and sometimes at subcutaneous tissues. MCC cells are gathered in groups, their sizes are unanimous, and their shapes look like lymphocytes. The cell nuclei of MCC looklike empty bubbles, and have many karyokinesis. The chromatin of MCC is very fine. The cytoplasms of MCC are little, and oxyphil staining. Immunohistological staining showed that both NSE (neuron-specific enolase) and CK(cytokeratin) are positive. The CT imaging of MCC is higher density. The MRI imaging of MCC is lower signals with unclear border in T1w and T2w, but becomes clear in enhanced MRI. Tumor cells invasion to soft tissues and bones could be seen on CT or MRI. Conclusion CT and MRI could clearly show the characteristics of MCC, and provide valuable information for operative treatment of MCC.