Mucinous carcinoma of the anal canal arising from perianal fistula

Abstract

Background

Anal carcinomas account for 1.5% of all gastrointestinal carcinomas. They may occur in the anal canal, perianal region (up to 5 cm) and surrounding skin. Squamous cell carcinoma (SCC) is the most frequent type (80%), while adenocarcinoma of the anal canal (ACC) accounts for 10% of all anal carcinomas. The remaining 5% includes neuroendocrine neoplasms, mesenchymal tumours, lymphomas, melanocyte tumours and secondary tumours. ACCs arise from chronic fistula or anal glands and they are very rare.

Methods

We report one case of rare adenocarcinoma that originated from perianal fistula. There is not definitive strategy about cure.

Conclusion

Inflammatory perianal tumour often causes late diagnosis or misdiagnosis of ACC, which is due to frequent perianal abscesses at the external perianal fistula opening. The presence of mucin may increase the index of suspicion for malignancy.

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