Pilonidal sinus of the umbilicus with urachal adenoma.
D000008:Abdominal Neoplasms / Q000209:etiology*; D000236:Adenoma / Q000209:etiology*; D000293:Adolescent; D006801:Humans; D008297:Male; D010864:Pilonidal Sinus / Q000150:complications*; D014496:Urachal Cyst / Q000150:complications*; D014497:Urachus