Interfollicular Classic Hodgkin Lymphoma: Report of a Case and a Brief Review of Literature.

Interfollicular Hodgkin lymphoma (IHL) has been rarely reported in the literature and is recognized by the WHO Classification as a morphologic pattern sometimes seen in mixed cellularity classic Hodgkin lymphoma (CHL). The changes may be subtle due to preservation of architecture. We report a case of a 9-year-old male with IHL showing preserved follicular architecture but with the presence of interfollicular infiltrates consisting of eosinophils, plasma cells, and Hodgkin-Reed-Sternberg (HRS) cells. Immunophenotyping confirmed the morphologic suspicion for IHL. A discussion and review of the literature are offered. We conclude that IHL is a variant that requires a high index of suspicion, as it may be easily missed due to the subtle morphologic features and preserved architecture seen in most cases. We further emphasize that unexplained interfollicular infiltrates of eosinophils may be clues that should prompt a search of HRS cells and consideration of immunohistochemical staining if needed.