CRA40 SMEAR-NEGATIVE GENEXPERT TRACE POSITIVE TUBERCULOSIS DIAGNOSES MASKING MALIGNANCIES: A CAUTIONARY CASE SERIES

Meryl Grace Lansing1,2, Larry Ellee Nyanti1,2 Ang See Qing 2, Hanafiah Semat 2, Awang Zarif Aminuddin 2, Lo Shan Min 2 Hema Yamini 2, Huan Nai Chien 2, Kunji Kannan Sivaraman Kannan 2
1. Medical Department, Faculty of Medicine and Health Sciences, Universiti Malaysia Sabah 2. Respiratory Department, Queen Elizabeth Hospital.

Introduction:

Diagnosing tuberculosis (TB) in patients with sputum smear-negative, GeneXpert® MTB/RIF Ultra trace-positive results poses significant challenges such as false positive results. This case series highlights four patients initially diagnosed with TB based on these criteria who were subsequently found to have malignancies. 

Objectives:

To emphasise the need of thorough follow-up and evaluation in patients with smear-negative, GeneXpert trace-positive TB diagnoses, to prevent misdiagnosis.

Methodology: We reviewed the clinical presentations, diagnostic processes, and follow-up outcomes of four smear-negative, GeneXpert trace-positive TB patients.

Results:

Case 1 was a 50-year-old-male who presented with epistaxis, an abnormal chest radiograph and sputum Xpert trace-positive. Endobronchial lesion biopsy revealed squamous cell carcinoma of the right upper lobe.

Case 2 was a 74-year-old male who presented with pleural effusion; ATT was commenced based on pleural biopsy Xpert trace-positive. Pelvic bone biopsy revealed metastatic adenocarcinoma of lung origin.

Case 3 was a 54-year-old male who presented with pleural effusion; ATT was commenced based on sputum Xpert trace-positive. Pleural biopsy later revealed metastatic adenocarcinoma.

Case 4 was a 62-year-old female who presented with dyspepsia and weight loss; ATT was commenced based on caecal biopsy Xpert trace-positive. Subsequent lung biopsy revealed adenocarcinoma of the lungs.

Conclusions:

GeneXpert trace-positive results should be interpreted with caution, especially when resistance patterns are indeterminate. Regular follow-up and thorough evaluation, including biopsy and histopathological examination, are crucial in presumed TB cases to avoid misdiagnosis and ensure timely treatment for underlying malignancies.