Nodular lymphocyte predominant Hodgkin lymphoma.

Nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) is a rare subtype of HL with unique clinicopathologic features. The hallmark histologic feature is the presence of malignant LP cells, unusual CD20(+)CD15(-)CD30(-) variants of Reed-Sternberg cells, embedded within a nodular pattern of infiltrating lymphocytes. Compared with classical HL, NLPHL shows a slightly older median age at presentation (30-40 years), greater male predominance (3:1), less mediastinal involvement (<15%), and lower occurrence of classical HL risk factors. The differential diagnosis includes progressive transformation of germinal centers, lymphocyte-rich classical HL, and T-cell/histiocyte-rich large B-cell lymphoma, the latter of which may share a common biologic relationship. The vast majority of patients present with limited stage disease (70%-80%), the standard treatment for which is involved field radiotherapy at 30-36 Gy. Response rates to primary therapy exceed 90%, although relapses are common and may occur years after the initial diagnosis. Secondary malignancies, particularly non-Hodgkin lymphoma, may also occur at a frequency similar to that of relapsed NLPHL. Patients with advanced stage disease may have lower response rates and overall survival times than those with limited stage disease. For relapsed disease, treatment options include the salvage therapies used in classical HL, and rituximab.