[Primary amelanotic anorectal melanoma--a case report]

Area of Science:

• Gastroenterology
• Oncology
• Surgical Oncology

Background:

• Amelanotic melanoma of the rectal mucosa is an exceptionally rare malignancy.
• It presents with a poor prognosis, and optimal surgical management remains debated.
• Transrectal ultrasound is crucial for preoperative staging and postoperative recurrence monitoring.

Observation:

• A 55-year-old female diagnosed with amelanotic rectal melanoma.
• Post-wide local excision and interferon therapy, she developed pararectal metastasis.
• Further treatment included abdominoperineal resection, inguinal lymph node dissection, and subsequent chemotherapy and radiotherapy.

Findings:

• The patient survived 36 months post-diagnosis despite aggressive multimodal treatment.
• Recurrence occurred despite initial negative margins and adjuvant therapy.
• Treatment progression involved multiple lines of chemotherapy and radiotherapy.

Implications:

• The prognosis for primary anorectal melanoma is poor, irrespective of surgical approach.
• Wide local resection is the preferred initial surgical treatment.
• Multimodal therapy including chemotherapy and radiotherapy may influence overall survival in advanced cases.