[Primary amelanotic anorectal melanoma--a case report]

Abstract

Background: The amelanotic melanoma of the rectal mucosa is very rare with an unfavourable prognosis. The surgical approach is still discussed controversially. Therefore transrectal ultrasound is of major importance in the preoperative staging and postoperative follow-up especially in diagnosis of local recurrence by using the ultrasound-guided, transrectal aspiration.

Methods: In literature 5 cases of amelanotic malignant melanoma were reported. The overall survival time is 10 months after diagnosis. All patients were female.

Results: We report about a 55-year-old female patient with an amelanotic melanoma of rectal mucosa. 7 months after a wide local excision of the tumour and interferon therapy in case of the absence of pararectal, inguinal metastases and other metastases the patient developed pararectal metastasis. An abdominoperineal resection and resection of inguinal lymph nodes was performed. Two months later paraaortal lymph nodes were detected. We started chemotherapy with Dacarbazin and with regard of the tumour progress the chemotherapy was changed to Vindesin 25 months after first operation supported by a radiotherapy with 40 Gray. The patient died 36 months after diagnosis.

Conclusion: The prognosis of primary malignant anorectal melanoma is poor, irrespective of surgical treatment. Wide local resection is the first choice for primary anorectal melanoma. Abdominoperineal resection should be reserved for cases were complete tumour resection is impossible. Chemotherapy, radiotherapy and immunotherapy should be considered in the treatment of anorectal melanoma to influence the overall survival.