Early cytological diagnosis of extranodal stage I, primary thyroid Non-Hodgkin lymphoma in elderly patients. Report of two cases and review of the literature

BACKGROUND: Primary thyroid lymphomas (PTLs) account for 5% of thyroid malignant tumors and often develop in patients with Hashimoto Thyroiditis (HT). Fine-needle cytology (FNC) is widely used in the diagnosis of thyroid nodules, including those arising in HT. Two PTL cases in HT elderly patients are here described and discussed. METHODS: FNC was performed in rapidly enlarged thyroid nodules of 2 elderly patients under ultrasound (US) control. FNC was used to prepare conventional cytologic smears, immunocytochemistry (ICC) and flow cytometry (FC) assessment of cell populations. RESULTS: The above cases were diagnosed as well differentiated, small B-cell and diffuse large B-cell thyroid lymphomas, respectively, by means of FNC. The histological diagnoses were mucosa-associated non Hodgkin lymphoma (MALT) and diffuse large B-cell lymphoma (DLBCL), confirming FNC diagnoses, and patients were treated accordingly. CONCLUSIONS: FNC diagnosis of PTL is reliable and accurate; it may be conveniently used in the clinical practice since it provides indications for appropriate therapeutic procedures or diagnostic surgery, and avoids to treat benign nodules.