A 17-year-old female presented to the physician with a 4 weeks history of fever, predominantly with evening rise of temperature. The temperature fluctuated between 37.7 and 38.8 C. She had no history of cough, haemoptysis or significant loss of weight. Neither a previous history of TB nor a recent exposure to TB was evident. Physical examination of the patient did not reveal any positive information as there was neither hepatosplenomegaly nor lymphadenopathy. Routine haematological investigations were found be largely within normal limits except for elevated C-reactive protein (39 mg l-1) and mildly elevated gamma-glutamyl transferase (56 Ul-1). Her haemoglobin was 11 g dl-1, with slightly reduced mean corpuscular volume, mean corpuscular haemoglobin and mean corpuscular haemoglobin concentration. The investigations for various types of fevers, including Widal test for typhoid/ paratyphoid, malarial parasite, leptospira immunoglobulin M antibodies, Weil Felix test for rickettsial infection, urine test and sputum and blood culture were non-contributing. She tested negative for retrovirus infection. No significant pathology was identified on her chest radiograph. Abdominal ultrasound scan was unremarkable (Figure 1). Finally, an 18-fluorodeoxyglucose (FDG)-positron emission tomography (PET)-CT scan was performed, which demonstrated multiple focal areas of abnormally high FDG uptake within the spleen (Figures 2, 3), which were not identifiable on CT scan images (non-contrast CT and contrast-enhanced images) (Figure 4). No other focal abnormalities were detected anywhere else. MRI of the abdomen was performed for further characterization of the splenic lesions. However, MRI abdomen, including diffusion-weighted images, did not show any nodules in the spleen (Figure 5). To avoid splenectomy for histopathological diagnosis, biopsy of the splenic lesions was planned, after ensuring that the coagulation profile was normal. True-cut biopsy was done by placement of a coaxial needle into one of the lesions under CT scan guidance, after carefully analysing the PET images.
Necrotizing granulomatous lesions suggestive of TB were identified on histopathology, as described in Figure 6a,b. The patient was started on antitubercular therapy for 9 months. The fever resolved by 3 weeks after the beginning of the treatment.