Clinicopathological features of primary thyroid Burkitt's lymphoma: a systematic review and meta-analysis

Background Primary thyroid Burkitt's lymphoma (BL) is an extremely rare and highly aggressive form of non-Hodgkin's lymphoma; only isolated case reports are available for patients with this disease. Methods We analyzed the clinicopathological features of thyroid BL by conducting a meta-analysis of 21 known patients (including ours) and compared them to those of extrathyroidal BL. Results There were 13 men and 8 women with a median age of 39.3 years (range, 6-75 years). The median follow-up was 46.5 months (range, 0.5-361 months). Six patients (28.6%) had stage I disease, 2 (9.5%) had stage II, 2 (9.5%) had stage III, and 11 (52.4%) had stage IV. Five of 7 tested patients with thyroid BL (71.4%) had histological evidence of underlying Hashimoto's thyroiditis. Ki-67 labeling indices exceeding 90% in all 19 patients tested (100%). Fluorescence in situ hybridization performed on 12 patient samples revealed that all (100%) had MYC rearrangement. Among the 16 patients for whom follow-up data were available, 4 died of disease-related causes. Kaplan-Meier analysis revealed that the 12- and 60-month overall survival rates for patients with thyroid BL were 87.5 and 70.7%, respectively. Conclusions Ours was the largest study of thyroid BL and its detailed clinicopathological features to date. Thyroid BL is not associated with underlying Epstein-Barr virus infection but is closely linked to Hashimoto's thyroiditis; patients generally have good overall survival and respond well to intensive chemotherapy. The correct pathological diagnosis is essential for treatment selection and outcome improvement.