CRA34 POSITIVE QUANTIFERON MASKS DIAGNOSIS

LF Tan1, MA Abdul Onny1, UN Daut2, T Abdul Aziz2
1 University Putra Malaysia, Serdang, Selangor, Malaysia
2 Hospital Sultan Abdul Aziz Shah, Serdang, Selangor, Malaysia

Introduction: 

Tuberculosis (TB) is an infectious disease which remains a significant public health challenge particularly in the least developed and developing countries. Among all tuberculosis cases, roughly 15-20% of all are extrapulmonary. Tuberculosis can affect various organs and sometimes mimic malignancy. Complete workup is needed for the correct diagnosis.   

Case report: 

A 56-years-old Somalia nation woman presented with chronic abdominal pain of 9 months followed by subacute intestinal obstruction symptoms. Further investigation done in Malaysia reveals TB QUANTIFERON positive and imaging showed bladder mass with involvement of colon and uterus. She was empirically started on anti TB considering high prevalence of tuberculosis in Somalia and her serious condition which definite diagnosis of either tuberculosis or malignancy is difficult to differentiate from the imaging. She then underwent exploratory laparotomy with ileostomy. Peritoneal lesion and bladder tissue histopathology examination reveals features of metastatic micropapillary urothelial carcinoma. 

Discussion: 

The QuantiFERON-TB Gold test is a widely used interferon-gamma release assay (IGRA) in Malaysia for detecting Mycobacterium tuberculosis infection. IGRA cannot distinguish between latent TB infection and active TB. Thus, it should not be used to diagnose active TB. In cases of diagnostic uncertainty, combining the results of biopsy histology, polymerase chain reaction (PCR) assays, and culture techniques significantly enhances the accuracy of tuberculosis diagnosis. 

Conclusion:

This case illustrates difficulties in distinguishing between extrapulmonary tuberculosis and malignancy due to possible similar clinical and radiological features. With the positive serological testing of TB QUANTIFERON, we often think tuberculosis is the culprit of the case, but this is not the case.  However, high clinical suspicious in high-risk patient for tuberculosis is needed to prevent mortality.