Primary signet‑ring cell melanoma of the anorectum: A case report

Malignant melanoma is one of the most common malignant tumors. Although its incidence rate is generally low among the Chinese population, it has grown rapidly in recent years. The incidence of primary malignant melanoma in the digestive tract is very low. The incidence in the esophagus and rectum are more common, while reports in the colon are only reported in <10 cases. Primary signet ring cell carcinoma of the rectum is also a rare and unique tumor. This paper reports a case of rectal malignant melanoma with signet ring cell carcinoma.