Middle mediastinal thymoma of unusual pathologic type.

Among the many sites of ectopic thymoma development, the middle mediastinum is the rarest in the English language literature we found only two case reports. We present a case of 69-year-old woman with slow-growing, ectopic middle mediastinum thymoma of an very unusual histological type, neither classified in the Müller-Hermelink nor the World Health Organization (WHO) classification.