An unusual presentation of primary lymphoma of the thyroid in a young male patient.

Primary lymphoma of the thyroid gland is a rare disease that is strongly associated with chronic lymphocytic thyroiditis. We report an unusual case of 20-year-old male who presented with thyroid swelling and was diagnosed on cytology as lymphocytic thyroidtis. However, histopathologicalfindings revealed non-Hodgkin's lymphoma that was further classified as B-cell type on immunohistochemical stains. In cytology, lymphomas must be considered as a differential diagnosis in case of Hashimoto's/lymphocytic thyroiditis, subacute thyroiditis and small cell carcinoma.