Rationale:Behçet disease (BD) is a recurrent vasculitis characterized by oral and genital mucous membrane ulcers, uveitis, and skin lesions but only rarely leg ulcers. To our knowledge, no efficacious therapy has been described for BD patients with complicating, destructive leg ulcers.Patient concerns:Here, We report the case of a 55-year-old woman with generalized erythema nodosum-like, papulopustular lesions, recurrent oral and genital ulcers accompanied with recurrent leg ulcers and trouble walking.Diagnoses:Based upon the patient's clinical feature and positive pathergy test , BD was confirmed.Interventions:Conventional immunosuppressive therapy and anti-tumor necrosis factor inhibitors, adalimumab and etanercept, had no demonstrable clinical effect. Mesenchymal stem cell (MSC) injection combined with low-dose prednisone and thalidomide, however, completely ameliorated the ulcers on one leg, significantly improved ulcers on the other leg, and returned normal function to both legs.Outcomes:The ulcerative lesions remained in remission, and the affected leg functioned normally after 34 months’ follow-up.Lessons:Our experience suggests that MSC infusion might be a potentially successful therapy for intractable drug-resistant BD patients with concomitant leg ulcer.