Clinicopathologic Analysis of Spindle Cell Myoepithelial Carcinoma Associated with Lymph Node Squamous Cell Carcinoma Metastasis

Objective To explore the clinical pathological features,diagnosis and differential diagnosis of spindle cell myoepithelial carcinoma with lymph node squamous cell carcinoma metastasis.Methods A case of spindle cell myoepithelial carcinoma of the submaxillary salivary gland with radical neck dissection was examined with light microsecopy and immunohistochemistry,and related literatures were reviewed.Results Microscopically,the tumor was composed of spindle-shaped cells and the cells were obviously atypical.Mitoses were seen usually with pellet necrosis and hyaline degeneration.Focal areas showed the ductile structure and the squamous cell carcinoma element.Metastatic squamous cell carcinoma(1/4) was seen in the lymph nodes of radical neck dissection.Immunohistochemically,the spindle tumor cells were strong positive for p53,partially positive for SMA and desmin,and negative for CK(AE1/AE3),S-100 protein,CD34,GFAP,CD10,and HMB45.Conclusion The myoepithelial carcinoma is a very rare malignant tumor.The spindle cell myoepithelial carcinoma may metastasize to lymph nodes,and its morphology is different from the primary tumor.The definite diagnosis should be based on the histopathological,immunohistochemical and electron microscope features.