| Theme |
Mesenchymal neoplasms of the colon and rectum : excluding lymphoproliferative disorders |
| Title |
Anorectal malignant melanoma |
| Author |
Tomohiko Moriyama |
Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University |
| Author |
Takayuki Matsumoto |
Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University |
| Author |
Hiroyuki Kobayashi |
Division of Gastroenterology, Matsuyama Red Cross Hospital |
| Author |
Shuji Tada |
Department of Gastroenterology, Saiseikai Kumamoto Hospital |
| Author |
Mitsuo Iida |
Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University |
| [ Summary ] |
Anorectal malignant melanoma (ARMM), which arises from melanocytes in the squamous epithelium, is a rare disease that represents about 1 % of all anorectal malignant tumors. Anal bleeding and anal masses are the main symptoms of ARMM. Endoscopically, most cases of ARMM are recognized as elevated lesions which are black in color. However, endoscopic diagnosis of amelanotic ARMM, which accounts for approximately 10 % of ARMM, is difficult. Histopathological examination usually shows spindle-shaped, pleomorphic cells. Immunohistochemical markers including S-100 and HMB-45 are useful for diagnosis. The traditional therapy for ARMM has been abdominoperineal resection (APR) with or without inguinal and pelvic lymphadenectomy. ARMM has poor prognose. While some authors advocate APR as the only treatment for a better prognosis, others have reported that long-term survival can also be achieved by wide local resection of primary tumors. Mean survival time of patients with ARMM is 9 months. |