A Case of Colonic Tuberculosis Revealed by Polymerase Chain Reaction

Area of Science:

• Gastroenterology
• Infectious Diseases
• Molecular Diagnostics

Background:

• Colonic tuberculosis can present as a tumor-like mass, complicating diagnosis.
• Conventional histological examination of colonic biopsies may not always detect tuberculosis.

Observation:

• A 32-year-old male presented with symptoms mimicking other gastrointestinal conditions, including constipation and abdominal pain.
• Imaging revealed a low-level peritoneal effusion, and colonoscopy showed colonic thickening.
• Initial colonic biopsy histology was negative for tuberculosis or malignancy.

Findings:

• Molecular analysis of the colonic biopsy using GeneXpert MTB/RIF PCR confirmed Mycobacterium tuberculosis complex.
• Conventional methods including Ziehl-Nielsen staining and cultures on Lowenstein-Jensen and MGIT media also yielded positive results.
• Rifampicin resistance was not detected in the Mycobacterium tuberculosis complex.

Implications:

• This case underscores the utility of molecular diagnostic techniques like PCR in identifying colonic tuberculosis when histology is inconclusive.
• Accurate and timely diagnosis is crucial for effective treatment and management of gastrointestinal tuberculosis.
• Colonic tuberculosis should be considered in the differential diagnosis of unexplained colonic abnormalities.