A case of thymoma diagnosed as cytologically malignant by percutaneous fine needle biopsy

Abstract

Biological behaviour of thymoma doesn't correspond with morphological finding incidentally and morphological nonmalignant thymoma sometimes shows metastasis or direct invasion to an adjacent organ. We have reported a case of malignant thymoma of 41-year-old male diagnosed as malignant thymoma by preoperative percutaneous fine needle biopsy.Chest X-ray examination showed anterior mediastinal mass lesion which invade to trachea and superior vena-cava. Fine needle biopsy specimen showed highly pleomorphic tumor cells with high N/C ratio surrounded by necrotizing cell debris.Nuclear chromatin was coarse and shape of nucleus was irregular.
Histological examination of operation material also showed nests of prominent atypical and pleomorphic tumor cells which invade into surrounding tissues.It was speculated such a type of thymic tumor could be diagnosed as thymic carcinoma.