Abstract: [abstract] Objective:  To study and research the clinical pathologic features ,immunohistochemistry and prognosis of epidermoid cyst with cancerous changes. Methods:  Six cases of epidermoid cyst with cancerous changes were studied to research the clinical pathologic features , immunohistochemistic expression and evaluate the prognosis by follow-up visits .Results:   Clinical features: six cases were all local bag piece and expanded resection. Follow-up of one year, No one have recurrence and metastasis. Pathological examination: they were all for not plastic masses and cystic,something like bean curd were in the cyst. Microscopic examination: These cysts lined by squamous epithelium and they presented invasive growth. Pathological diagnosis: Epidermoid cyst canceration of squamous cell carcinoma. Immunophenotype: Squamous cell cancer of six cases were positive expressions of CK5/6 and P63. Conclusion:   Epidermoid cyst with cancerous changes are quite rare.Diagnosis of the tumor relies largely on histopathology.Immunohistochemical markers assist the diagnosis. Local appropriately expanded resection is preferred. The malignant degree is low and prognosis is good.

Key words: epidermal cyst, carcinoma, squamous cell, immunohistochemistry