Studies have highlighted components of immune dysregulation in HS that support the use of biologic agents that target TNF-α, IL-1β and IL-10 [30,31] The success of the TNF-α antagonists in the treatment of HS is documented in many case reports, and recent clinical trials provide more robust evidence for the efficacy and safety of treatment with adalimumab at 40 mg per week [32,33]. Here, TNF is linked to histiocytic sarcoma.