Is the identification of caseating granuloma in the intestine indicative of tuberculosis? a rare case of Crohn's disease

Abstract

Background: Crohn's disease (CD) is a chronic intestinal inflammatory disorder, the etiology of which remains unknown, and is characterized by symptoms such as chronic abdominal pain, diarrhea, obstruction, and perianal lesions. Histopathology is widely regarded as the preferred method for diagnosing CD, although the histological diagnosis may lack specificity. The identification of granulomas is commonly believed to be the most reliable diagnostic indicator for CD, surpassing all other clinical features in significance. Nevertheless, research indicates that the detection rate of granulomas in CD exhibits considerable variability. Furthermore, granulomas can manifest in various specific infections including tuberculosis and Yersinia, as well as in a range of diseases characterized by macrophage reactions such as sarcoidosis and drug-induced enteritis. Granulomas associated with CD typically do not exhibit necrosis. However, the formation of caseous granulomas may occur as a result of secondary infections related to anti-CD drug treatment or perforation of the intestinal wall.

Case presentation: In this study, we present a case of a 28-year-old female patient diagnosed with CD exhibiting histologic granulomas, including both caseating and non-caseating forms, which demonstrated a positive response to medical treatment.

Conclusion: In clinical practice, various forms of granulomas may indicate diverse underlying diseases, yet lack specificity. It is suggested that the presence of caseous granulomas should not be considered as a definitive exclusion criterion for the diagnosis when clinical, endoscopic, imaging and other histopathological features are consistent with CD. This study is the first report of caseous granulomas in CD without concomitant tuberculosis infection.

Keywords: Case report; Caseating granuloma; Crohn’s disease; Specific bacterial infections; Tuberculosis.

Fig. 1

Imaging manifestations. a Enhanced CT revealed partial thickening of the wall of the small intestine. b MRI with contrast enhancement of the anal canal demonstrated the presence of an anal fistula

Fig. 2

Histopathological evidence. a The histological examination revealed a modification in the structure of the recess, and the development of non-caseous granulomas within the submucosal lymphoid tissue was found; 10×magnification. b Inflammation throughout all layers of the intestinal wall was examined histologically; 4×magnification. c-d Granulomas. c indicates non-caseous granuloma in the submucosa of the intestinal wall; 20×magnification. d displays a caseous granuloma in the subserosa of the intestinal wall, with surrounding isolated multinucleated giant cells; 20×magnification

Fig. 3

Comparison of endoscopy findings before and after pharmacological intervention. a Endoscopy revealed the presence of multiple ulcers located at the anal margin. b Following 7 months of treatment with CD, the anal margin ulcer was successfully healed as confirmed by endoscopic examination