A Case of Long-term Follow-up of Severe Hidradenitis Suppurativa of the Buttocks Treated With Free and Pedicled Flap.

Long-term outcomes of flap surgery for hidradenitis suppurativa (HS) of the buttocks have not been reported. We encountered a case of severe HS in which multiple new lesions appeared during a 27-year follow-up period. This article reports useful information regarding reconstruction using a free flap from the back. The patient was a 62-year-old Japanese man. At the age of 35 years, he developed HS in the bilateral groin and sacral regions. Reconstructive surgery was performed for the left groin using a left pedicled rectus abdominis flap, for the right groin using a left free scapular flap, and for the sacral region using a mesh skin graft. During the follow-up period, new lesions appeared in the axilla, face, buttocks, and lower extremities and were primarily treated with deroofing and skin grafting. Subsequently, no recurrent lesions were observed in the sacrum, left buttock, or axilla, and only mild recurrence was observed in the scapular flap transplanted to the right groin. In such severely affected patients, initially harvesting a flap from a distal area rather than an adjacent area may reduce the burden of any subsequent surgery. In particular, the incidence of HS has been reported to be low in the back, and HS did not occur in this patient. This report describes the challenges of buttock reconstruction for progressive severe HS, the advantages of using a free flap from the back during the initial surgery, and the favorable long-term results achieved.