ABSTRACT Objective: Thyroid lymphoma constitutes a rare presentation of extranodal, diffuse, large B-cell lymphoma (DLBCL) and represents a small proportion of thyroid cancers. In this article, we present a case report of extranodal DLBCL presenting with simultaneous thyroid, abdominal, and retroperitoneal involvement. We also review the relevant epidemiologic literature and treatment modalities of thyroid lymphoma as well as providing a potential pathophysiologic mechanism. Methods: A literature search was conducted using the databases PubMed and Google Scholar for primary thyroid lymphoma and extranodal lymphoma involving the thyroid. Publications were selected based upon size of patient cohorts, treatment modalities investigated, quality of the data, as well as subsequent citation frequency. Articles most recently published, and therefore belonging to the post-rituximab era, were favored. Results: Thyroid lymphoma in the presence of concurrent abdominal disease usually presents with goiter with or with...