Nodular lymphocyte-predominant Hodgkin lymphoma of the tonsil: a case study using immunohistochemistry and FISH analysis and review of the literature

Abstract

Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is a rare subtype of Hodgkin lymphoma that differs from classic Hodgkin lymphoma with respect to histological and clinical presentations. This type of lymphoma typically affects predictable lymph node groups with excellent treatment outcomes. However, rare atypical locations have also been described and a possible diverse clinical or biological subtype has been suggested. We present a case of NLPHL arising in the tonsil of a 43-year-old man. The patient presented with a submucosal mass in an asymmetrically enlarged tonsil. Bilateral tonsillectomy was performed and histological examination showed effacement of the enlarged tonsil by nodules comprised of scattered large atypical cells having classic lymphocyte-predominant cell morphology in a background of benign B cells. Immunohistochemical analysis showed lack of CD15 and CD30 in the LP cells and strong expression of CD20, CD45, BCL-6 and epithelial membrane antigen (EMA). Interphase fluorescence in situ hybridization (FISH) analysis, revealed bcl-6 gene rearrangement in the LP cells. Although lymphoma is a common malignancy of the tonsil, there are only sporadic reports of NLPHL arising in this location and the differential diagnosis should include this entity. Histological, immunohistochemical and FISH findings are also discussed and the literature reviewed.