Pathologic proved the case of thymic carcinoma.

Microscopic description: Sections show fibroconnective tissue infiltrated by nests and sheets of round to ovaloid small tumor cells with hyperchromatic nuclei, indistinct nucleoli, and scant eosinophilic cytoplasm. some mitotic figures are noted. No necrosis is identified. foci of squamous differentiation are also noted. 

IHC staining is positive for cytokeratin, EMA, P63, CK7, CK 20, C-kit, CD5 and CK 5/6.

Morphologic study and IHC staining are in favor of thymic carcinoma.