| Abstrakt: |
Introduction: Anorectal malignant melanoma is an aggressive disorder, with poor prognosis and metastases in the majority of newly-discovered cases. Patients often present with symptoms mimicking a thrombosed haemorrhoid, rendering early diagnosis a challenging task. Digital rectal examination and proctosigmoidoscopy, endoluminal ultrasound, computer tomography (CT) and magnetic resonance imaging set the diagnosis, and immunohistostaining provides confirmation. Case presentation: An 81-year-old woman reported rectal bleeding, modified defaecation pattern, tenesmus, lack of appetite, unusual dislike of meat, and weight loss. An ulcerated fragile tumour at the anal verge (macroscopically resembling adenocarcinoma) was identified during rectosigmoidoscopy. The tumour was confirmed by an abdominal CT scan. The patient underwent abdomino-perineal resection (APR). Immunohistochemical staining of the malignant cells was performed and proved positive for HMB-45, S-100 and NSE proteins, confirming the diagnosis of malignant melanoma of the anal canal. Discussion: Anorectal melanoma is a rare disorder that should be considered in the differential diagnosis of all cases of atypic anal pathology, mainly in females older than 50 years. It is diagnostically differentiated from other malignant tumours by positive HMB-45 and S-100 immunohistostaining. At present, there is no consensus as to the best surgical approach. It seems that the treatment of choice for small tumours is local excision, but for large and obstructing tumours APR is preferred. Wide local excision is a controversial method. Chemotherapy seems ineffective, while immunotherapy could potentially be effective. Radiation therapy is an effective palliative therapy in up to 50% of patients who have developed unresectable, locally recurrent and/or metastatic disease resulting in disease-associated complications. [ABSTRACT FROM AUTHOR] |
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