Anorectal melanoma: Report of two cases

Abstract

Introduction: Anorectal melanoma (AM) is a rare and aggressive type of cancer. Its symptoms often resemble those of common benign anal conditions, such as hemorrhoids, leading to frequent delays in diagnosis. Consequently, about one-third of patients have metastases at the time of their initial diagnosis. The primary treatment for AM is surgical resection, while adjuvant therapies may include immunotherapy, radiotherapy, brachytherapy, and chemotherapy. The prognosis for AM is poor, with a five-year survival rate of only 20 %.

Case presentation: In this study, we report two cases of patients who experienced different anorectal symptoms for a long time before their condition worsened, prompting further investigation that revealed a diagnosis of malignant anorectal melanoma. Both patients underwent surgical resection and are currently receiving adjuvant therapy.

Discussion: This article discusses the prognosis of anorectal melanoma, the current lack of consensus on treatment protocols, and the importance of maintaining a high index of suspicion for early diagnosis.

Conclusion: Anorectal melanoma is a rare pathology, and its prognosis is poor due to the frequent presence of metastatic forms at the time of diagnosis. Surgery, whether through abdominoperineal amputation or wide local excision, is the treatment of choice for these tumors. The use of radiotherapy (RT) is controversial and is currently indicated either as hypofractionated therapy following local excision (EL) or as palliative treatment.

Keywords: Anal margin; Chemotherapy; Melanoma; Rectal; Resection.

Fig. 1

Surgical specimen from an abdominoperineal amputation (Oncological Surgery Department, Hassan II Oncology Center).

Fig. 2

CT image showing non-stenosing tumoral parietal thickening of the lower rectum.

Fig. 3

Image of an operating specimen, anorectal melanoma treated by wide resection (Oncological surgery department at the Hassan II Oncology Center in Oujda).