Is repeat wide excision plus radiotherapy of localized rectal melanoma another choice before abdominoperineal resection? A case report

Background: Rectal melanoma is an uncommon neoplasm that accounts for approximately 1 percent of rectal cancer cases. Abdominoperineal resection was regarded as the radical procedure for disease control. Nevertheless, it led to more postoperative complications than sphincter-sparing wide local excision (WLE) and reduced the patient's quality of life (QOL) owing to creation of colostomy. Therefore, in this study, WLE, radiotherapy (RT), and a second WLE were conducted on a patient who had been diagnosed with localized rectal melanoma.

Case summary: The patient was a 79-year-old woman who had been experiencing anal pain and bloody stool for 1 mo. Colonoscopy, magnetic resonance imaging, positron emission tomography-computed tomography, and histological analysis of tissue biopsy using the histological markers Melan-A (+), S-100 (+), and Ki-67 (+, 50%) lead to the diagnosis of localized rectal melanoma. The patient had initially undergone WLE to resolve problem of anal bleeding, followed by RT to treat the residual lesion with partial response. Subsequently, the residual lesion was removed with margin-free resection by the second WLE. The patient's postoperative course was smooth and uneventful. During the 2-year follow-up, no local recurrence was observed. Additionally, a good functional outcome and improved QOL were reported.

Conclusion: Combining WLE, RT, and repeat WLE is proposed as a viable alternative for treating rectal melanoma accompanied by bleeding symptoms that cannot be completely resected at the beginning.