Secondary Thyroid Lymphoma Due to CLL

Introduction: Background: Thyroid lymphomas are a rare finding among thyroid malignancies, and Chronic Lymphocytic B-cell (CLL-B) type of thyroid lymphoma is even more infrequent. Lymphomas compose only 2% of thyroid malignancies, with primary thyroid lymphomas constituting only 2.5% of all lymphomas. Chronic lymphocytic B-cell (CLL-B) type of thyroid lymphoma (CLL-B) is is exceptionally rare, with only 4% of cases ever reported worldwide. Case Presentation: A 55-year-old female presented with a complaint of swelling over the anterior part of neck. She had a pre-existing diagnosis of CLL, fine needle aspiration biopsy (FNAB)of the swelling revealed lymphocytic proliferation, classified as Bethesda grade II. The patients was in a euthyroid state and a ‘core-needle’ biopsy was performed to confirm the diagnosis of lymphocytic infiltration of the thyroid. The patient was managed conservatively and is currently under regular follow-up. Conclusions: The occurrence of thyroid swelling in CLL is a rare phenomenon, and confirming the diagnosis through biopsy is recommended. Surgeons should be cautious not to be deceived by the rarity of the swelling and avoid unnecessary surgical interventions. Conservative management has been the prevailing approach in the literature. This case report serves to support this conservative approach and contributes to the existing literature on Thyroid lymphoma due to CLL.