Mucinous adenocarcinoma associated with a chronic perianal fistula - a review of cases from a single institution.

Purpose: The purpose of this study was to evaluate the clinicopathological features of mucinous adenocarcinoma associated with perianal fistulas (MAF), to assess the importance of preoperative MRI analysis, and to determine the optimal surgery.

Methods: We performed a retrospective analysis of the data from seven patients with MAF treated at our hospital between 2000 and 2013, and herein discuss the importance of preoperative magnetic resonance imaging (MRI) and of radical surgery.

Results: The male to female ratio was 5:2, and the mean age of the patients was 63 years old (28-70). The median duration of chronic fistulation was 16 years (5-40). The tumor extension was classified as II+III+IV in five patients and as II+III in 2 patients according to the Sumikoshi classification, as determned by pelvic MRI. The performed surgeries were 3 abdominoperineal resections with sacral resection and 4 pelvic exenterations with sacral resection. Two local recurrences developed in patients with R1 resection, and 1 distant metastasis occurred in 1 patient with R0 resection.

Conclusion: For patients with MAF, a curative surgical resection is the only definitive treatment that can be expected to provide a good prognosis. The application of the Sumikoshi classification using MRI may provide a precise assessment of the extension of MAF, which can allow the appropriate surgery to be selected for the patients with MAF.