Primary thyroid lymphoma: a tertiary-center experience

Primary thyroid lymphoma (PTL) is a rare thyroid malignancy, usually presenting as a rapidly enlarging neck mass. We aimed to describe its clinical, biochemical, imaging, and pathological features.

Retrospective single-center study, including 20 patients diagnosed with PTL between 2000 and 2023 (median age 76 years, range 47-84; 85% female). Clinical presentation, thyroid function, imaging, histopathology, treatment, and outcomes were reviewed.

Nineteen patients (95%) presented with a rapidly growing neck mass with a median duration of one month. Compressive symptoms occurred in 70%, and B symptoms in 20%. Hypothyroidism was present in 45%, and thyroid autoimmunity in 67% of patients with available data. Ultrasound (performed in 16 patients) showed hypoechoic nodules in most cases, with a mean size of 49.7 mm; cervical lymphadenopathy was observed in 20%. Fine-needle aspiration (FNA) suggested lymphoma in 78%. Histological confirmation was obtained by core-needle biopsy in 70%, incisional biopsy in 10%, and surgery in 15%. Nineteen patients (95%) had diffuse large B-cell lymphoma, and one had mucosa-associated lymphoid tissue (MALT) lymphoma. At presentation, 59% had localized disease, 12% regional, and 29% disseminated. Two patients died before treatment. Most received R-CHOP (rituximab, cyclophosphamide, adriamycin, vincristine, and prednisolone) or reduced-dose R-CHOP (R-miniCHOP); three also underwent radiotherapy. Complete remission was achieved in 61% of patients. Median follow-up was 2.5 years.

PTL should be suspected in patients with a rapidly enlarging thyroid mass. While FNA is often informative, biopsy is usually required for diagnosis. Most cases are diffuse large B-cell lymphoma, with chemotherapy as the mainstay of treatment. Larger studies are needed to refine diagnostic pathways and prognostic markers.