ALK and primary effusion lymphoma: The large, atypical cells were negative for pan-B cell markers, ALK, HHV8, and CD15, and positive for CD45LCA, which ruled out nodular lymphocyte predominant Hodgkin lymphoma, T cell/histiocyte rich large B cell lymphoma, classic Hodgkin lymphoma, ALK positive B cell lymphoma, and cavitary primary effusion lymphoma.