Thymoma with extensive necrosis: a case report and review of literature.

Thymoma exhibiting extensive necrosis is extremely rare and remains a diagnostic challenge for both radiologists and pathologists. We describe such a thymoma in an 18-year-old African-American female. Core needle biopsy contained only necrotic tumor tissue. A well-encapsulated 13-cm anterior mediastinal thymoma with extensive necrosis and areas of hemorrhage was resected. Microscopically, the thymus was almost completely replaced by tumor composed of plump epithelial cells with vesicular nuclei and prominent nucleoli in a background of lymphocytes and extensive necrosis. The clinical, immunohistochemical and diagnostic pitfalls of this tumor in core needle biopsies is discussed.