Anorectal emergencies

Figure 1 Acutely thrombosed external hemorrhoid (A, B) and anal melanoma (C, D).

Figure 2 Urgent hemorrhoidectomy for thrombosed internal hemorrhoids (A-D).

Figure 3 Rectal prolapse (A), strangulated rectal prolapse (B), and perineal rectosigmoidectomy or Altemeier’s procedure (C, D).

Figure 4 Three-dimensional endoanal ultrasonography of horseshoe abscess (A), cross-sectional view (B), coronal view (C) and sagittal view (D). The asterisk means abscess in ischiorectal space and the triangle means abscess in deep postanal space.

Figure 5 Perineal necrotizing fasciitis (Fournier gangrene) (A-D).

Figure 6 Obstructing rectal cancer: plain abdominal radiography (A), computerized tomography (B), and endoscopic view (C). T3 rectal cancer (white arrow) and perirectal lymph node (arrow head).