Burkitt lymphoma presenting as a mass in the thyroid gland: a clinicopathologic study of 7 cases and review of the literature.

Burkitt lymphoma presenting in the thyroid gland is rare, and only a few cases have been reported. We retrospectively reviewed 7 patients diagnosed with Burkitt lymphoma of the thyroid gland between 2000 and 2015. There were 4 men and 3 women with a median age of 41 years (range, 19-49 years). All patients presented with a rapidly growing neck mass associated with upper airway compression in 5 (71%) patients. Two patients presented with localized (stage I/II) and 5 patients with disseminated (stage III/IV) disease. All cases showed morphologic and immunophenotypic features of Burkitt lymphoma with MYC rearrangement in all 5 cases tested. One case showed evidence of concurrent Hashimoto thyroiditis. Six of 7 patients were treated primarily with rituximab, hyperfractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone. One patient was treated primarily with dose-adjusted rituximab, etoposide, prednisolone, vincristine, and cyclophosphamide. At the end of the study period, 5 patients were alive: 4 in complete remission and 1 with persistent disease. Two patients died with persistent disease (median follow-up, 25 months; range, 12-361 months). We conclude that Burkitt lymphoma of the thyroid gland shows clinicopathologic features similar to sporadic Burkitt lymphoma at other anatomic sites, but patients present at an older median age. The clinical course is aggressive with a high frequency of disseminated disease at diagnosis; however, a subset of patients responds well to aggressive chemotherapy.