Case Study: Unlocking resemblance between tuberculosis and cancer

Abstract

Tuberculosis (TB) has often been found to mimic malignancy in clinical and radiological features, and therefore it is well known as a diagnostic chameleon. Although the differences between pulmonary TB and lung cancer have been highlighted by several reports, TB often gets misdiagnosed as lung cancer and vice versa. It is therefore vital to discern the imaging results specific to pulmonary TB and its diverse forms to distinguish it from lung cancer. In the present study, a 72-year old female (HIV-negative, non-smoker), complaining of persistent cough, low chest pain, pain around kidneys and significant weight loss up to 8 kg in 4 months, was advised to undergo X-ray examination along with CT scan. The CT scan results showed manifestation of ill-defined lesions along the right main bronchus with partial atelectasis and multiple scattered centrilobular nodules in the right upper lobe. There was also a well-defined lesion at the left adrenal gland. Also, several sub-centimetre mediastinal nodes were found. The preliminary assessment by the doctor indicated lung cancer, and therefore PET scan was advised for further confirmation, also to detect any metastasis of malignancy if lung cancer is confirmed. PET scan results ruled out lung cancer; afterwards, the TB test (AFB smear) was recommended by the doctor. The final reports of the test results confirmed tuberculosis. However, this is not the only case where tuberculosis has been found to mimic lung cancer; there have been several case studies reporting misdiagnosis of TB. A correct diagnosis could only be achieved through high-imaging techniques or invasive examination. The present case expanded the clinical knowledge in the diagnosis of TB and also invigorated clinicians to consider pulmonary TB in the differential diagnosis and treatment. The study also accentuates the importance of 18FFDG-PET to differentiate TB from lung cancer.