XVIII. Management of nodular lymphocyte predominant Hodgkin lymphoma.

Nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) represents only ~5% of Hodgkin lymphoma (~1.5 per 1000000 people per year) [1,2].Microscopically, NLPHL displays a nodular growth pattern, although a diffuse growth pattern with prominent histiocytes and T cells can be seen in advanced or recurrent cases. The malignant cells of NLPHL, referred to as LP or ‘popcorn cells’ because of their microscopic appearance, express CD20, and immunophenotyping, is critical for establishing the diagnosis. LP cells express B-cell-associated antigens CD20, CD45, and CD79a and often J-chain but lack expression of CD15 and CD30 [3]. Immunophenotypic and molecular studies demonstrate a clonal relationship between LP cells and cells of concurrent or subsequent diffuse large B cell lymphoma, suggesting a common cell of origin. Progressive transformation of germinal centres can be mistaken for NLPHL; however, the transformed germinal centres do not harbour cells expressing the typical immunophenotype of LP cells [3].