Curious case of fever of unknown origin.

A 58-year-old immunocompetent woman presented with fever and significant weight loss of 4-month duration. She had mild pallor; rest of the examination was unremarkable. Investigations revealed anaemia with raised inflammatory markers. Cultures, serologies, routine urine examination, bone marrow examination, contrast enhanced CT and two-dimensional echocardiography examination were unremarkable. An 18F-fluorodeoxyglucose positron emission tomography with CT (18F-FDG-PET/CT) scan was performed which revealed atypical heterogenous uptake in bilateral renal cortex. Subsequently, urine GeneXpert came positive for Mycobacterium tuberculosis with sensitivity to rifampicin. She responded to category 1 antitubercular therapy. The challenges in diagnosis of genitourinary tuberculosis, low sensitivity of conventional diagnostic tests and potential role of GeneXpert and 18F-FDG-PET/CT scan are discussed in this report.