Mucinous adenocarcinoma arising from chronic perianal fistula—a multidisciplinary approach

Perianal fistula (PF) is a common entity in the proctology area. However, the development of a mucinous adenocarcinoma (MA) arising from chronic anal fistula is extremely rare. The relation between both entities was first described by Rosser et al. in 1934, who reported seven cases of fistula that had undergone malignant transformation (1). The pathogenesis of this malignancy is still controversial. MA has an indolent growth and, although metastases to inguinal lymph nodes may be present in advanced cases, distant metastases are uncommon (2-4). However, these locally aggressive neoplasms entail a high probability of local recurrence. The subtle symptoms that resemble a fistula-associated perianal MA to an inflammatory benign pathology make an early diagnosis difficult (5)