Peritoneal tuberculosis mimicking malignancy on FDG PET/CT in a patient with ankylosing spondylitis on adalimumab: a diagnostic challenge

Document Type : Case report

Authors

1 Department of Nuclear Medicine, Jawaharlal Institute of Postgraduate Medical Education Research, Puducherry, India

2 Department of Nuclear Medicine, Institute of Post Graduate Medical Education and Research, Kolkata, West Bengal, India

Abstract

Tumor necrosis factor-alpha (TNF-α) inhibitors, such as adalimumab, are integral in the managing refractory ankylosing spondylitis (AS). However, their immunosuppressive effects elevate the risk of reactivation of latent tuberculosis (TB), especially extrapulmonary TB (EPTB), which can present with non-specific symptoms and mimic malignancy.
We report the case of a 40-year-old man with ankylosing spondylitis who had been on long-term adalimumab therapy. He presented with a low-grade fever and weight loss. An 18F-FDG PET/CT scan revealed intense FDG uptake in the peritoneum, omentum, and mesentery. There was no ascites or visceral involvement; however, a few FDG-avid retroperitoneal, mediastinal, and right cervical lymph nodes were noted, along with a right pleural effusion and no lesions in the lung parenchyma. Despite a negative microbiological workup, empirical anti-tubercular therapy (ATT) was initiated due to strong clinical and imaging suspicion of tuberculosis. The patient showed significant clinical improvement, and a follow-up PET/CT scan six months later indicated complete metabolic resolution of the lesions.
This case underscores the diagnostic challenge of peritoneal TB in immunosuppressed individuals. It highlights the supportive role of FDG PET/CT in guiding empirical therapy and monitoring treatment response without microbiological confirmation.

Keywords

Main Subjects

References

  1. Braun J, Sieper J. Ankylosing spondylitis. Lancet. 2007; 369(9570):1379-1390.
  2. Keane J, Gershon S, Wise RP, Mirabile-Levens E, Kasznica J, Schwieterman WD, et al. Tuberculosis associated with infliximab, a tumor necrosis factor α–neutralizing agent. New England Journal of Medicine. 2001; 345(15):1098-104.
  3. Dixon WG, Hyrich KL, Watson KD, Lunt M, Galloway J, Ustianowski A, et al. Drug-specific risk of tuberculosis in patients with rheumatoid arthritis treated with anti-TNF therapy: results from the British Society for Rheumatology Biologics Register (BSRBR). Annals of the rheumatic diseases. 2010; 69(3):522-8.
  4. Sharma MP, Bhatia V. Abdominal tuberculosis. Indian Journal of Medical Research. 2004; 120(4): 305-315.
  5. Ling CW, Sud K, Castelino RL, Johnson DW, Tan THY, Lee VW. Systematic Review on Treatment and Outcomes of Tuberculous Peritonitis in Patients on Peritoneal Dialysis. Kidney International Reports. 2023; 9(2): 277-286.
  6. Burrill J, Williams CJ, Bain G, Conder G, Hine AL, Misra RR. Tuberculosis: a radiologic review. 2007; 27(5): 1255-1273.
  7. Vorster M, Sathekge MM, Bomanji J. Advances in imaging of tuberculosis: the role of ¹⁸F-FDG PET and PET/CT. Current Opinion in Pulmonary Medicine 2014; 20(3):287-293.
  8. Engin G, Acunaş B, Acunaş G, Tunaci M. Imaging of extrapulmonary tuberculosis. Radiographics. 2000; 20(2): 471-532.
  9. Martinez V, Castilla-Lievre MA, Guillet-Caruba C, Grenier G, Fior R, Desarnaud S. 18F-FDG PET/CT in tuberculosis: an early non-invasive marker of therapeutic response. The International journal of tuberculosis and lung disease. 2012; 16(9): 1180-5.
  10. Guidance for National Tuberculosis Programmes on the Management of Tuberculosis in Children. 2nd edition. Geneva: World Health Organization; 2014.
  11. Wallis RS. Tumour necrosis factor antagonists: structure, function, and tuberculosis risks. The Lancet infectious diseases. 2008; 8(10): 601-11.
  12. Solovic I, Sester M, Gomez-Reino JJ, Rieder HL, Ehlers S, Milburn HJ, et al. The risk of tuberculosis related to tumour necrosis factor antagonist therapies: a TBNET consensus statement. European Respiratory Journal. 2010; 36(5): 1185-206.
  13. Bomanji J, Sharma R, Mittal BR, Gambhir S, Qureshy A, Begum SM, et al. PET/CT features of extrapulmonary tuberculosis at first clinical presentation: a cross-sectional observational 18F-FDG imaging study across six countries. European Respiratory Journal. 2020; 55(2):1901959.
  14. Duvivier A, Goyers JF, Radermacher J, Namur [Hypermetabolic multifocal steatohepatitis: a rare case of [18F] FDG PET/CT false positive mimicking a metastatic carcinomatosis].Revue Medicale de Liege. 2022; 77(7-8): 430-4.
  15. Abi El Hessen T, Saleem S, Hani RH, Chadli FZ, Makarem JA. Peritoneal Tuberculosis Mimicking Peritoneal Carcinomatosis in an Immuno-competent Patient. Cureus. 2022; 14(11): e31464.
Asia Oceania Journal of Nuclear Medicine and Biology
Volume 14, Issue 1
January 2026
Pages 126-129

Files

Share

How to cite

Statistics