Fine-needle aspiration cytology diagnosis of non-Hodgkin lymphoma of thyroid: a report of four cases.

Four cases of non-Hodgkin lymphoma of thyroid, diagnosed by fine-needle aspiration (FNA) cytology during a period of 3 1/2 yr constituted 0.2% of 1,716 thyroid FNAs and 3.4% of 118 thyroid neoplasms. The age of the patients ranged from 42 to 78 yr with an average of 63 yr and all were females. Three cases had thyroid swellings, and one case had cervical lymphadenopathy and fullness in the thyroid region. The lymphomas were categorized as mixed small and large cell lymphomas, large cell lymphoma, small noncleaved lymphoma (non-Burkitt-type), and plasmacytoid lymphoma. Histopathology as well as immunohistochemistry confirmed the cytodiagnosis of lymphoma in the first and fourth cases. In the second case where possibility of anaplastic carcinoma could not be ruled out altogether at initial cytologic examination, the histopathology report was undifferentiated carcinoma but immunohistochemically it was proved to be a B-cell neoplasm.