Benign Anorectal: Anal Fissure

Abstract

An anal fissure, or fissure-in-ano, is an oval, ulcer-like, longitudinal tear in the anal canal, distal to the dentate line. Fissures can occur at any age, but are usually seen in younger and middle-aged adults. In almost 90% of cases, fissures are identified in the posterior midline, but can be seen in the anterior midline in up to 25% of affected women and 8% of affected men. Fissures occurring in lateral positions should raise suspicions for other disease processes, such as Crohn’s disease, tuberculosis, syphilis, human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS), or anal carcinoma (Fig. 12.1). Early, or acute, fissures have the appearance of a simple tear in the anoderm, whereas chronic fissures, defined by symptoms lasting more than 8–12 weeks, are further characterized by edema and fibrosis. Typical inflammatory manifestations of chronic fissures include a sentinel pile, or skin tag, at the distal fissure margin and a hypertrophied anal papilla proximal to the fissure in the anal canal. In addition, fibers of the internal anal sphincter (IAS) are often visible at the fissure base.