Coexisting and clonally identical classic hodgkin lymphoma and nodular lymphocyte predominant hodgkin lymphoma

We report a case of concurrent nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) and classic Hodgkin lymphoma (cHL), of nodular sclerosis subtype, in an otherwise healthy 24-year-old man with a strong family history of cHL. The patient was found to have a parotid mass, which was diagnosed as NLPHL, and a thymic mass diagnosed as cHL, of nodular sclerosis subtype concurrently. The lesion in the parotid showed features typical of NLPHL by morphology and immunophenotype. The LP cells were positive for PAX5, CD20, Oct2, weakly positive for CD30, and negative for CD15. The thymic lesion, diagnosed as cHL, of nodular sclerosis subtype, showed prominent bands of fibrosis and Hodgkin/Reed-Sternberg and lacunar cells positive for CD30 and CD15. These cells were variably positive for CD20 and negative for Oct2. PAX5 was weakly positive. Immunoglobulin gene rearrangement studies by polymerase chain reaction were carried out on microdissected Hodgkin/Reed-Sternberg and LP cells, which were shown to have identically sized peaks. NLPHL and cHL are 2 distinct diseases and are almost never seen concurrently. We present a case in which polymerase chain reaction analysis indicated that the tumor cells of these 2 distinct entities were clonally identical.