Hypertrophic colonic tuberculosis mimicking tumourous mass.

Intestinal tuberculosis is a diagnostic challenge, particularly in the absence of active pulmonary infection. It mimics many other abdominal diseases, such as other infectious processes, tumours, periappendiceal abscess and Crohn’s disease. A case of primary intestinal tuberculosis without pulmonary disease is presented. A 40-year-old male was admitted with episodic right lower quadrant pain and weight loss (10 kg in 6 months). He was anaemic (haemoglobin 10.2 g ⁄ dl) and had a high erythrocyte sedimentation rate (76 mm ⁄ h). Other biochemical parameters were normal. Colonoscopy revealed a mass lesion at the ileocaecal valve (Fig. 1). The initial endoscopic diagnosis suggested a malignant lesion, but histological examination of biopsies showed chronic inflammation and noncaseous granulomas with Langhans giant cells (Fig. 2). Staining for acid-fast bacilli was negative. Although he had no history of tuberculosis, the patient’s father had been treated for pulmonary tuberculosis 4 years previously. The tuberculine skin test was 18 mm. Urine and stool cultures for acid-fast bacilli were all negative, as was PCR analysis. Chest radiography showed fibro-calcific signs in the apices of the lungs, but computed tomography was normal. Antituberculosis therapy was started and the patient’s condition improved on a four-drug regimen (isoniazide, pyrazinamid, ethambutol and rifampicine). He gained 15 kg during therapy and a colonoscopy 9 months later was normal. At this time the patient was free of symptoms and the antituberculous treatment was stopped. Tuberculosis can affect any part of the gastrointestinal tract but the most common site is the ileocaecal region. Lesions can be ulcerative, hypertrophic or a combination of both. Hypertrophic lesions are rare but can mimic a mass lesion as in our patient [1]. The PCR analysis of biopsy specimens obtained endoscopically has been shown to be more sensitive than culture and acid-fast stains in diagnosing intestinal tuberculosis, with positivity in 60% of colonic biopsies [2–4]. In our patient, histological examination of colonic biopsies showed noncaseous granulomas with Langhans giant cells, which are commonly seen in tuberculosis, sarcoidosis and Crohn’s disease. Sarcoidosis was excluded by the normal chest X-ray and normal angiotensinconverting enzyme levels. We also excluded Crohn’s disease as mass lesions are extremely rare. Histologically it is difficult to differentiate tuberculosis Crohn’s disease, but large granulomas (> 400 lm) and caseation gave a positive predictive value of 100% for tuberculosis in Pulimood’s study [5]. In our patient there were two large granulomas and caseation in the biopsy material, although staining of acid-fast bacilli was negative. This case illustrates that the diagnosis of colonic tuberculosis requires a high index of suspicion. Colonoscopic biopsy histology is a useful method for diagnosing colonic tuberculosis. Figure 1 Colonoscopy showing a mass lesion at the ileocaecal valve. Figure 2 Colonic biopsy showing a noncaseating granuloma.