Table 1 Retrorectal tumours.
Congenital (55-6 5%): | Osseous (5- 11%): | Miscellaneous (12-16%): |
|---|---|---|
Developmental cyst (up to 60% of congenital lesions): | Osteoma | Metastatic carcinoma |
| Â | Osteogenic sarcoma | Lipoma/liposarcoma |
   Dermoid | Ewing's tumor | Fibrosarcoma |
   Epidermoid | Chondromyxosarcoma | Leiomyoma/leiomyosarcoma |
Tailgut cyst | Giant cell tumor | Hemangioma |
Teratoma | Inflammatory (5%): | Carcinoid tumors |
Teratocarcinoma |    Perineal or pelvirectal abscess | Hemangioendothelial sarcoma |
Chordoma |    Diverticulitis | Extra-abdominal desmoid |
Anterior sacral meningocele |    Crohn's disease | Plasma cell myeloma |
Rectal duplication |    Foreign body granuloma | Endothelioma |
Adrenal rest tumor |    Infectious granulomas | Pelvic ectopic kidney |
Neurogenic (10 -12%): | Â | Â |
   Neurofibroma |  |  |
   Ependymoma |  |  |
   Neurilemoma (Schwannoma) |  |  |
   Ganglioneuroma |  |