恶性原发性直肠黑素瘤（PRM）是一种罕见的肿瘤。由于这些病灶常常被误认为是良性疾病，导致诊断延误，患者的整体生存率非常低。组织学评估和特殊的免疫组织化学染色经常是确诊的必要手段。这种疾病的主要治疗方式是外科切除，辅助治疗也一直备受推荐。我们讨论了一位60岁的女性病例，患者主诉排便习惯改变、肛门疼痛和会阴烧灼感，但没有出血症状。肛门指诊发现有一结节状肿块从距肛缘5厘米处延伸。直肠乙状结肠镜检查显示糜烂型息肉样肿瘤从离肛缘4厘米处延伸至直肠下段5厘米以上。活检和免疫组织化学试验确定了直肠黑素瘤的诊断。患者经过手术治疗后接受外束放射治疗，随访10个月后实现了完全缓解。 版权所有 © 2023年，El Youssi等人。

Malignant primary rectal melanomas (PRM) are rare tumors. Their diagnosis is frequently delayed as these lesions are often mistaken for benign diseases, resulting in extremely poor overall survival. Histological evaluation with special immunohistochemical (IHC) stains is often indispensable for a definitive diagnosis. The main treatment for this condition involves surgical resection. Adjuvant therapy has also been long recommended. We discuss the case of a 60-year-old woman who presented with changes in bowel habits, anal pain, and perineal burning with no bleeding. A digital rectal examination revealed a nodular mass extending 5 cm from the anal verge. Rectosigmoidoscopy demonstrated an ulcerated polypoid tumor extending 4 cm from the anal verge and over 5 cm into the lower rectum. Biopsy and IHC tests confirmed the diagnosis of rectal melanoma. The patient was successfully managed with surgery followed by external beam radiotherapy and a complete response was achieved after 10 months of follow-up.Copyright © 2023, El Youssi et al.