Primary Burkitt Lymphoma of the Thyroid Associated With Hashimoto Thyroiditis Masquerading as Post-COVID Thyroiditis.

Primary thyroid lymphoma accounts for only 2% to 5% of all thyroid tumors, and Burkitt lymphoma of the thyroid is even rarer than other types of B-cell lymphoma. It is a highly aggressive non-Hodgkin lymphoma characterized by intermediate-sized lymphoid cells with a "starry sky" appearance and exhibits chromosomal translocations that activate the MYC oncogene. A male predominance and an aggressive clinical course with a high risk of central nervous system involvement and tumor lysis syndrome are all well-recognized features of Burkitt lymphoma. We present a case of a 28-year-old man with primary Burkitt lymphoma of the thyroid initially misdiagnosed as post-COVID thyroiditis. Core needle biopsy showed round, intermediate-sized lymphoid cells admixed with scattered tingible body macrophages displaying a "starry sky" appearance. Following the final histological diagnosis of primary thyroid Burkitt lymphoma, the patient received intensive chemotherapy. Six months after the diagnosis, the patient succumbed to disease progression, causing upper airway obstruction. Primary Burkitt lymphoma of the thyroid can cause pain and other symptoms due to the rapidly growing mass in the neck. Adequate pathological diagnosis with core needle biopsy rather than fine needle aspiration is essential for treatment planning and outcome improvement.