ABSTRACT
Objective: Primary thyroid lymphoma (PTL) is a rare entity, necessitating accurate and early diagnosis, as its management is very different from that of other neoplasms intrinsic to the thyroid. Materials and Methods: Cases diagnosed between January 2009 and March 2015 were retrieved, and clinical details were noted. Hematoxylin- and eosin-stained slides were reviewed. Immunohistochemistry (IHC) was performed for immunophenotyping, and cases were classified according to the World Health Organization 2017 classification of hematolymphoid neoplasms. Results: Eleven patients with PTL were identified, with a mean age of 64.6 years (range: 40–76 years), including three males and eight females. Duration of symptoms ranged from 2 to 36 months (mean: 9.3 months). Diffuse large B-cell lymphoma (DLBCL) was most frequent, followed by extranodal marginal zone lymphoma. Most DLBCLs were nongerminal center type. BCL2 was positive in all DLBCLs. Strong p53 immunopositivity was not seen in any of the cases analyzed. Conclusion: Histopathological evaluation supplemented by IHC is the gold standard for the diagnosis of PTL. Combined chemoradiotherapy appears to be the best treatment modality, irrespective of histological type. MIB-1 and MUM1 IHC may have a role in identifying DLBCL, particularly in small biopsies. Role of p53 and BCL2 needs further evaluation