<prompt> All are true regarding Hodgkin;s lymphoma, except -CNS is the commonest site of involvementCharacteristic cell is a Reed Sternberg cell AI2KMediastinal involvement is common in nodularsclerosis typeEosinophils, plasma cells and neutrophils increase  <response>: Hodgkin lymphoma arise in a single lymph node or a chain of lymph nodes typically spread in a stepwise fashion to anatomically contiguous nodes. Extranodal involvement is uncommon.Reference : Robbins basic pathology 9th edition pg no 440 