Ileocaecal and transverse colonic tuberculosis mimicking synchronous colonic malignancy

A 55-year-old man presented with on-and-off constipation, dull abdominal pain associated with weight loss, low-grade fever and loss of appetite for one year. He was not known to have pulmonary tuberculosis. On examination, he was vitally stable with soft, non-tender abdomen with normal digital per rectum examination.

The erect abdominal radiograph(figure 1) shows an abnormally distended and faecalised bowel loop in the subhepatic region.

His chest radiograph was normal.

An ultrasonogram of the abdomen shows asymmetric circumferential thickening with loss of mural architecture of the ileocaecal junction (Figures 2). The ascending colon is dilated (figure 2).

Contrast-enhanced CT of the abdomen shows pulled-up ileocaecal junction and short segment asymmetric circumferential proliferative enhancing thickening and loss of mural architecture at the ileocaecal junction(figure 3); and proximal one-third of the transverse colon(figure 4). The ascending colon is abnormally dilated and faecal-loaded. Axial sections show few enlarged homogeneously enhancing mesenteric and retroperitoneal lymph nodes, some of them show calcification(Figures 5a and 5b).

Background

Large bowel thickening is one of the frequent findings in CT of the abdomen. Short segment bowel wall thickening can be neoplastic, granulomatous, inflammatory or due to lymphoma. It is essential to differentiate them because the management varies significantly. The mechanisms which may lead to bowel involvement in tuberculosis are :

1. Ingestion of bacilli in infected sputum or contaminated food [1]

2. Reactivation of a quiescent intestinal focus resulting from hematogenous dissemination in the childhood

3. Hematogenous dissemination of active tuberculosis or direct spread from other organs

Sites of involvement- Ileocecal valve, terminal ileum and cecum (most common).

Complications- obstruction, perforation, pericolic abscess formation, sinuses, and fistulae [2,3].

Clinical Perspective

The patients may be asymptomatic or present with abdominal pain, weight loss, anaemia, and low-grade fever. Most of them will have findings of pulmonary tuberculosis. Imaging is needed to narrow the differential diagnosis of this clinical picture and suggest the possibility of tuberculosis, differentiate it from other bowel pathologies and look for complications. Knowing the extent of the disease is useful during the follow-up period and to tailor the treatment.

Imaging Perspective

Abdominal CT findings. The most common finding is mural thickening, typically concentric, but it tends to involve the mesenteric caecal wall if eccentric. Localized lymphadenopathy is usually seen. Skip areas of concentric mural thickening with associated luminal narrowing with or without proximal dilatation can occur elsewhere in the bowel, findings that strongly suggest tuberculosis in the presence of ileocecal involvement [4,5]. 

Outcome

Our patient underwent right hemicolectomy (figure 6), and histopathology (figure 7) suggested granulomatous inflammation with caseous necrosis. Therapeutic options- Anti-tuberculous therapy is the mainstay of treatment in most patients. Surgical intervention is reserved for complications—fibrosis, strictures, and acute abdomen—or when there is uncertainty in the diagnosis.

Take Home Message

Short segment bowel wall thickening in middle-aged/elderly patients may not be neoplastic. Imaging is essential to narrow the differentials and look for complications.

All patient data have been completely anonymised throughout the entire manuscript and related files.