Original article doi:10.1111/j.1463-1318.2008.01698.x The value of routine histopathological analysis in patients with fistula in-ano N. S. Wijekoon and D. N. Samarasekera University Professorial Surgical Unit, The National Hospital of Sri Lanka, Colombo, Sri Lanka Received 9 July 2008; accepted 18 August 2008 Abstract Objective To determine the positive yield of routine histopathology in patients undergoing surgery for fistula in-ano. Method Histopathology reports of all the patients who underwent surgery for fistulae-in-ano over a period of 36 months were reviewed. Results Analysis included 84 patients of which 73 (87%) were male subjects. The mean age was 39.4 years (range 11–68). Forty-one (49%) had recurrent fistulae. Granu- lomatous diseases such as Crohn’s disease and tubercu- losis (TB) were suspected in six patients. However, of the six patients, confirmation of the disease status was obtained only in three patients: stains for acid-fast bacilli confirmed TB in two (2.4%) patients and colonoscopy and biopsy confirmed Crohn’s disease in one (1.2%) patient. All three patients had recurrent fistulae. Conclusion As the positive yield of routine histopathol- ogy is minimal, we do not recommend routine histopa- thology for fistula in-ano, except for those presenting with recurrent fistulae and those with clinical suspicion of an underlying disease such as TB, HIV or Crohn’s disease. Keywords Fistula in-ano, histopathology, tuberculosis, Crohn’s disease Introduction Fistula-in-ano is a common benign anal condition encountered in general surgical practice with a mean incidence of 8.6 per 100 000 population [1]. Most of the simple anal fistulae have a benign course, but complex, recurrent fistulae are associated with a chronic course and frequent acute exacerbations requiring repeated surgical interventions. In addition, these repeated surgical interventions carry a significant risk of damaging the anal sphincter mech- anism that may even result in anal incontinence [2–5]. Some of these fistulae may have a medically manage- able underlying aetiology such as Crohn’s disease, tuberculosis (TB) or actinomycosis. Histopathological analysis of the surgical specimens in these patients may facilitate the diagnosis of above aetiological factors. Studies analysing the histopathology of resected surgical specimens in patients with perianal fistulae are very few [6]. Method The histopathology reports of all the patients who underwent surgery for fistulae-in-ano over a period of 36 months at the University Surgical Unit of the National hospital of Sri Lanka were reviewed. The age, gender and the histopathological findings were recorded from their histopathology reports. The Ethics Committee of the National Hospital of Sri Lanka approved the study. Results Eighty-four patients underwent surgical treatment for fistula-in-ano during this period. Histopathological assessment of all the fistula tracts was carried out during each procedure. There were 73 (87%) male- and 11 (13%) female patients. The mean age was 39.4 years (range 11– 68). Of the 84 patients, 41 (49%) had recurrent fistulae. No significant histopathological change other than a fistula tract was present in 74 (88.1%) patients. Six (7.1%) patients had granulomatous changes on histology, and exclusion of Crohn’s disease and TB as an aetiology was suggested. Three (3.6%) had foreign body type reactions. Noncaseating granulomata and microabscess formation was noted in one (1.2%) patient. Correspondence to: Prof D. N. Samarasekera, 28 ⁄ 1, Ishwari road, Colombo 06, Sri Lanka. E-mail: samarasekera58@yahoo.co.uk 94 Ó 2010 The Authors. Journal Compilation Ó 2010 The Association of Coloproctology of Great Britain and Ireland. Colorectal Disease, 12, 94–96