Snapshot A 17-year-old male presents with lower back pain. He reports that the pain worsens when he sits or bends forward. Medical history is significant for metabolic syndrome. He is a high school student who spends hours playing online computer games. On physical exam, there is a tender and fluctuant mass that is erythematous. There is also purulent discharge from a sinus tract. Introduction Clinical definition login to view 1 more bullet Epidemiology Incidence login to view 1 more bullet Demographics login to view 1 more bullet Location login to view 1 more bullet Risk factors login to view 7 more bullets EitIoLOGY Pathophysiology login to view 5 more bullets Presentation Symptoms login to view 7 more bullets Physical exam login to view 4 more bullets Studies Diagnostic criteria login to view 1 more bullet Differential Perianal abscess Hidradenitis suppurativa Anorectal fistula Folliculitis Perianal furuncle and carbuncle Perianal complications from Crohn's disease Treatment Operative login to view 6 more bullets Complications Cellulitis Abscess Squamous cell carcinoma login to view 1 more bullet Prognosis Approximately 50% of patients with acute pilonidal cyst may develop a chronic pilonidal cyst Approximately 20% of cases treated with initial surgery have recurrence of the disease