Anorectal melanoma: not a haemorrhoid

Area of Science:

• Oncology
• Surgical Oncology
• Gastroenterology

Background:

• Anorectal melanoma is a rare and aggressive malignancy, often presenting with symptoms mimicking hemorrhoids.
• Delayed diagnosis is common due to its rarity and non-specific symptoms, impacting patient prognosis.

Observation:

• This paper reviews four cases of anorectal melanoma from a New Zealand institution.
• Patients presented with anal discomfort or rectal bleeding, with three showing metastatic disease at initial diagnosis.

Findings:

• Surgical excision, particularly transanal excision, is the primary treatment for anorectal melanoma.
• Transanal excision offers survival outcomes comparable to abdominoperineal resection with reduced morbidity.
• Metastatic disease at presentation is a significant negative prognostic indicator.

Implications:

• Increased awareness and a high index of suspicion are vital for early diagnosis of anorectal melanoma.
• Transanal excision represents a less morbid surgical option for local control.
• Current adjuvant therapies offer limited survival benefits for advanced anorectal melanoma.