TNF and histiocytic sarcoma: Scheinfeld [28] recognized seven types of HS associated pain: “(1) neuropathic pain; (2) inflammatory/joint-related pain; (3) non-inflammatory/non-neuropathic pain; (4) ischemic pain; (5) pain related to inflammatory mediators, such as tumor necrosis factor alpha (TNFa) and IL-1β; (6) pain associated with depression, anxiety and emotional stress; and (7) pain associated with arthritis.” Management of pain in HS is complex.