Tuberculosis - The master of disguise: A case of disseminated tuberculosis masquerading as metastatic cancer.

Abstract

Tuberculosis (TB) is an airborne infectious disease caused by Mycobacterium tuberculosis (MTB). Although it typically affects the lungs (pulmonary TB), one-fifth of TB cases present as extrapulmonary TB. The diagnosis of extrapulmonary TB is often overlooked due to its atypical clinical and radiological manifestations. Differentiating TB from neoplastic conditions poses significant challenges. A 33-year-old female patient was admitted to the emergency clinic with shortness of breath, cough, and abdominal pain. Postero-anterior chest X-ray revealed massive pleural effusion leading to mediastinal shift. With a preliminary diagnosis of malignant pleural effusion, a pleural catheter was inserted, and the patient was referred for a positron emission tomography (PET/CT) to assess the primary site and the optimal location for a biopsy. The PET/CT revealed asymmetric soft tissue thickening on the left side of the nasopharynx, and increased fluorodeoxyglucose (FDG) uptake in the left cervical lymph nodes raised suspicion regarding primary nasopharyngeal cancer. Additionally, there was an increased FDG uptake observed in the mass lesion located in the right upper lobe, mediastinal lymph nodes, pleural surfaces in the left hemithorax, perihepatic areas, and peritoneum, indicating diffuse metastatic disease. Tuberculosis diagnosis was confirmed through biopsies demonstrating granulomatous inflammation in the lung and nasopharynx, along with culturing MTB from pleural effusion. Positron emission tomography played a crucial role in identifying sites of TB involvement. Despite its rarity, healthcare professionals should consider nasopharyngeal TB as a potential diagnosis when evaluating nasopharyngeal masses.