Significance of granuloma and granulomatous lymphangitis in the differential diagnosis of Crohn's disease

Abstract

Objective: To clarify the pathological characteristics of granuloma and granulomatous lymphangitis in patients with non-neoplastic bowel diseases and to compare their significance in the differential diagnosis of Crohn's disease (CD) and intestinal tuberculosis (ITB).

Methods: Altogether 78 cases with CD, 11 with ITB and 33 suffering from other non-neoplastic bowel diseases were included. All patients underwent a partial enterectomy and histopathological examination. Pathological sections were reviewed retrospectively. Detailed morphological features and the distribution of granulomas and granulomatous lymphangitis in the three groups were analyzed and compared.

Results: Significant differences in the features of granuloma were observed in CD compared with ITB, including the presence of Langhans giant cells, caseous necrosis, coalescence, hyaline change, onionskin changes, and their frequency and size. Granulomatous lymphangitis was significantly more frequent in CD than in other non-neoplastic bowel diseases (P < 0.0001). The rate was also higher than that of granuloma in CD (P = 0.0004). It more often manifested within the mucosal layer of the small bowel (55.4%) in CD whereas it tended to be located within the deep layers of the intestinal wall in other diseases. It can be divided into four types, but types 1 and 2 appeared relatively specific to CD.

Conclusions: Granuloma and granulomatous lymphangitis were not specific in CD. However, by combining morphology and distribution, their manifestations could assist in the differentiation of CD from other non-neoplastic bowel diseases. Furthermore, granulomatous lymphangitis showed better diagnostic performance than granulomas in the mucosal layer of the small bowel.

Keywords: Crohn disease; granuloma; granulomatous lymphangitis; histopathology; intestinal tuberculosis.