A CASE OF MALIGNANT AMELANOTIC MELANOMA SUGGESTIVE OF RETROPERITONEAL ORIGIN

• Published in: Nihon Rinsho Geka Gakkai Zasshi (Journal of Japan Surgical Association) Vol. 64; no. 8; pp. 2032 - 2036
• Main Authors: NAKUI, Minoru, OTANI, Yasuo, KASHIWAGI, Hiroyuki, TSUKUI, Masaru, ISHII, Masanori, MAKUUCHI, Hiroyasu
• Format: Journal Article
• Language: English
• Published: Japan Surgical Association 2003
• Subjects: 5-S-Cysteinyldopa (5-S-CD)
• ISSN: 1345-2843; 1882-5133
• DOI: 10.3919/jjsa.64.2032

We report a case of amelanotic malignant melanoma (AMM) suggestive of retroperitoneal origin. A 68-year-old man seen at elsewhere because of intensifying left back pain which was first felt in May 1995 was found to have an about 8-cm tumorous lesion adjacent to the pancreatic body and tail on an abdominal ultrasonography and an abdominal CT scan. The patient was referred to the hospital. On admission close examinations revealed no abnormal findings in the skin, eyes and gastrointestinal organs. Abdominal CT scan visualized multiple lymph node swellings in the abdominal cavity, so that malignant lymphoma and mesenchymal tumor as well as pancreatic epithelial tumor were suspected. In order to make the definite diagnosis, a laparoscopic biopsy of the lymph node was conducted. Small nodules 10 mm in size were sporadically existed in the abdominal cavity, and a part of them was callected and histopathologically studied. As a result, a histological picture of amelanotic malignant melanoma in which almost no melanin granules were seen was revealed. Malignant melanoma arisen in the retroperitoneum is extremely rare and almost all cases of malignant melanoma reported so far are of the adrenal medulla origin. This is the fourth case of malignant melanoma which appeared to be originated from retroperitoneum other than adrenal gland.