The differentiation between Crohn's disease and tuberculosis of the intestine can be difficult in areas where both diseases occur.
Dr Pulimood and colleagues from India examined histological criteria that would enable the diagnosis in mucosal biopsies.
The research team analyzed colonoscopic biopsies from 33 patients with tuberculosis and 31 patients with Crohn’s disease for several specific histological features and their distribution.
|There was an accrual in the number of diagnoses with increasing numbers of biopsies|
|Journal of Gastroenterology and Hepatology|
The salient distinguishing features of tuberculosis were granulomas larger than 400 µm in maximum dimension.
Other distinguishing features of tuberculosis included more than 4 sites of granulomatous inflammation per site as well as caseation.
The team also considered a band of epithelioid histiocytes in ulcer bases and location of granulomas in the caecum as distinguishing features of tuberculosis.
The researchers reported that the salient features of Crohn’s disease were granulomas not showing any of the above features, and also included focally enhanced colitis and pericryptal granulomatous inflammation.
In addition, salient features of Crohn’s disease included and the presence of architectural alteration/inflammation or deep ulceration at sites that did not show granulomatous response in the same or adjacent segments.
The investigators found that although granulomas in Crohn’s disease were distributed throughout the colon, they were more frequent in the rectosigmoid than in tuberculosis.
The investigative team observed that all biopsies from endoscopically abnormal sites did not show distinguishing features of tuberculosis or Crohn’s disease.
The researchers emphasized the need for multiple biopsies.
The team also noted that there was an accrual in the number of diagnoses made with increasing numbers of biopsies from rectum to ileum.
Dr Pulimood concluded, “The histology of mucosal biopsies can aid in the differentiation of tuberculosis from Crohn’s disease, but multiple biopsies from different colonic segments are important for complete evaluation.”