TNF and Cowden disease: In a year-long study of 22 patients with isolated perianal disease and 44 with perianal CD, treatment with tumor necrosis factor (TNF)-antagonists resulted in fistula healing in 43% of patients with perianal CD and 19% of patients with isolated perianal disease.9 This corresponds to the 31% response rate to biologics in our present case series of patients with isolated perianal disease.