Summary

Primary thymic carcinomas are rare neoplasms, and several pathologic variants of such neoplasms have been described. Well-differentiated squamous, low-grade mucoepidermoid, and basaloid carcinoma usually are associated with a favorable prognosis, but other variants are agressive. Our first case is a 57-year old woman with a 6 cm. anterior mediastinal mass. Pathological examination of the tumor revealed epithelial nests with a spindle cell sarcomatous component, and also chondroid areas. A diagnosis of “thymic carcinoma of sarcomatoid type” was made. The second case is a 21-year old woman with a 5,5 cm. anterior mediastinal mass. Pathological examination of the tumor revealed epithelial nests in desmoplastic stroma. Immunohistochemically, the tumor cells showed expression of cytokeratin. Chromogranin also was expressed in a minority of cells, and thus, a diagnosis of “thymic carcinoma with focally neuroendocrine differentiation” was made. Here, we report 2 rare and agressive cases of thymic carcinoma.