Thymic carcinoma, part 1: a clinicopathologic and immunohistochemical study of 65 cases.

The clinicopathologic and immunohistochemical features of 65 primary thymic carcinomas are reported (43 men and 22 women; 19-81 years old). Thymectomy was performed in all cases. Masaoka staging for 53 patients showed 3 patients in stage I, 14 in stage II, 17 in stage III, and 19 in stage IV. Histologic studies revealed 9 carcinoma subtypes. Immunohistochemically, the tumors showed high rates of expression for cytokeratin, Pax8, and FoxN1. Follow-up for 62 patients revealed that 36 patients were alive (mean follow-up, 51.1 months) and 26 had died (mean survival, 47.5 months). The 3- and 5-year overall survival rates were 76.6% and 65.7%, respectively. Our findings suggest that thymic carcinomas may behave less aggressively than commonly believed. Lymph node status and tumor size seem to be important prognostic factors. The Masaoka staging system does not seem to reliably predict outcome.