Giant cystic thymoma with haemorrhage and necrosis: an unusual case.

Extreme degree of cystic, haemorrhagic and necrotic changes in a thymoma is rare. A 22-year-old male presented with cough, grade 2 dyspnoea, and occasional chest pain for the past six months. Radiological investigations revealed a large cystic lesion in the anterior mediastinum. A benign cystic tumour was suspected. Surgical resection of the tumour was done. Grossly, the almost entirely cystic and haemorrhagic dumb-bell shaped encapsulated tumour showed a subcapsular residual nodule. Histopathological examination was suggestive diagnosis of benign thymoma (World Health Organization [WHO] Type A, medullary type) associated with the rare features of cells with dendritic processes containing melanin pigment seen singly scattered throughout the tumour.