Features of Thyroid Lymphoma: A Single-Center Experience

Primary thyroid lymphoma (PTL) is a rare malignancy, accounting for less than 5% of thyroid cancers and less than 2% of extranodal lymphomas. It predominantly affects older women and is strongly associated with autoimmune thyroiditis, particularly Hashimoto's thyroiditis. Diagnosis is often challenging due to non-specific clinical, imaging, and cytological findings, and the role of surgery has progressively shifted from therapeutic to primarily diagnostic.

We conducted a retrospective single-center case series including nine patients treated for PTL between 2015 and 2025 at a tertiary referral endocrine surgery center. An analysis was conducted on clinical presentation, pre-existing thyroid disease, diagnostic work-up, histopathological subtypes, treatment strategies and outcomes. All patients underwent preoperative ultrasound and fine-needle aspiration cytology (FNAC); surgical intervention was performed to confirm cytology results, when cytology was inconclusive or when compressive symptoms were present.

The cohort included six females and three males, with a median age of 65.2 years. Four patients had Hashimoto's thyroiditis and three had multinodular goiter. FNAC was diagnostic or suggestive of lymphoma in three cases only, and surgical biopsy or thyroidectomy for a definitive diagnosis was performed in eight cases. One case started follow-up after cytology and flow cytometry. Histological subtypes were heterogeneous, including diffuse large B-cell lymphoma, Burkitt's lymphoma, Hodgkin lymphoma, follicular lymphoma, high-grade B-cell lymphoma, and MALT lymphoma. Seven patients received combined chemoimmunotherapy. A complete response was obtained in eight patients, with a minimum follow-up of three years; one patient died of unrelated causes.

PTL remains a rare and diagnostically challenging thyroid malignancy. FNAC alone is frequently insufficient, and surgical biopsy retains an important role in cases with high clinical suspicion or compressive symptoms. While surgery has limited therapeutic value, a multidisciplinary approach and timely, tailored treatment are crucial to achieving favorable outcomes.