Diffuse variant of lymphocyte-predominant Hodgkin lymphoma: a diagnostic challenge

The diffuse variant of nodular lymphocyte-predominant Hodgkin lymphoma (D-LPHL) is exceedingly rare. Here we report a case of D-LPHL in a 35-year-old Caucasian female who presented with left cervical and right axillary lymphadenopathy. Histopathologic examination reveals large atypical lymphoid cells resembling lymphocyte-predominant (LP) cells in a background of reactive T cells, B cells, and histiocytes. Extensive immunohistochemical study demonstrates that these large atypical lymphoid cells express characteristic phenotype of LP cells including CD20, CD79a, BOB-1, OCT-2, BCL-6, and EMA and are negative for CD30 and fascin. The diffuse nature of the lymphoid proliferation is confirmed by negative CD21, CD23, and CD35 stains showing a complete lack of follicular dendritic cell meshworks. The associated T cell microenvironment shows increased CD57(+) T cells arranged into peritumoral cell rosettes. The diagnostic criteria of this case are discussed and a review of the literature about the differential diagnosis is provided.