Primary anorectal melanoma: Multimodality management in a series of four cases and review of literature

Anorectal melanoma is a very rare and aggressive mucosal melanocytic malignancy, accounting for 1% of all anorectal cancers. There have only been a few cases reported. Surgical resection remains the mainstay of treatment. No definitive management strategies exist because of the absence of randomized trials. We here report a case series on four cases of anorectal melanoma. All four cases underwent abdominoperineal resection (APR) and nodal dissection. Two out of four cases received adjuvant temozolomide (TMZ), one case received adjuvant doublet chemotherapy with TMZ and cisplatin, and the fourth case succumbed to nononcological disease before he could be subjected to adjuvant chemotherapy. In the first and third case, nodal dissection was limited to pelvic nodes only. However, in the second case, extensive nodal dissection in the form of bilateral pelvic and inguinal lymph nodal dissection and para-aortic lymph nodal dissection was performed. The fourth case also was subjected to extensive nodal dissection in form of bilateral pelvic and para-aortic lymph node dissection. The first patient however became metastatic at the end of first cycle of adjuvant TMZ and succumbed to his illness post 3 months of surgery. The second patient could complete all six cycles of adjuvant TMZ, and after 1 year of completion of adjuvant TMZ, he presented with skeletal and brain metastases. He also received palliative whole-brain radiotherapy for brain metastases. He finally succumbed to his disease 18 months after surgery. The third case completed all six cycles of adjuvant TMZ and is still alive with disease-free interval of around 1 year. The fourth case succumbed to nononcological death around 1 month after surgery.