Fistula-associated anal carcinoma in Crohn’s disease

INTRODUCTION: Fistula-associated anal carcinoma in patients with Crohn's disease (CD) is a rare condition. More recently, this entity has been increasingly reported likely due to increased recognition, and the incidence may be greater than once appreciated. There remains a paucity of data regarding the incidence, diagnosis, treatment, and outcome of fistula-associated anal carcinoma. Area covered: This review evaluates the clinical features, pathology, treatment, and prognosis of fistula-associated anal carcinoma in patients with CD. A strategy for surveillance of this carcinoma is proposed by the authors based on the evidence obtained from this review. Expert commentary: Clinicians caring for patients with CD and perianal involvement need to be aware of the rare yet extremely important association of long-standing perianal disease and fistula-associated carcinoma. Only through awareness, a high level of suspicion will be diagnosed in a timely manner. This involves a thorough history, a proper, and complete anorectal examination, along with early imaging and examination under anesthesia. Through this approach, it is hoped that early diagnose can be achieved in at-risk patients and change the significant morbidity and mortality associated with this diagnosis.