Unmasking a Malignancy Mimic: Diagnostic Challenges and Outcomes in Pseudotumoral Tuberculosis

Abstract RATIONALE: Pseudotumoral tuberculosis (TB), an uncommon malignancy-mimicking form of pulmonary TB, often causes diagnostic delays, especially in patients without TB history or immunosuppression. In TB-endemic areas, reliance on negative sputum culture or GeneXpert results—even from fibro aspiration—can lead to misdiagnosis. A comprehensive approach, including biopsy and radiologic assessment, is crucial for accurate diagnosis. This study evaluates the diagnostic yield of various modalities, describes key clinical, radiologic, and bronchoscopic features, and underscores the need to consider TB in the differential diagnosis of pulmonary masses. METHODS: This retrospective study included 35 patients diagnosed with pseudotumoral TB, 82% of whom presented with isolated pulmonary involvement. Demographics, clinical presentations, radiologic and bronchoscopic findings, diagnostic methods used, and treatment outcomes were analyzed. Patients underwent diagnostic evaluation with sputum analysis (culture and GeneXpert), bronchial biopsy, bronchial aspiration, and CT-guided biopsy, with each modality's observed diagnostic contribution documented to assess utility within this population. RESULTS: The clinical presentation was largely nonspecific, with 62-79% of patients presenting with symptoms like dyspnea, cough, and weight loss, while fever was observed in only 44%. This frequent absence of fever contributes to an initial misdiagnosis as malignancy. Radiologically, 55% of cases displayed nodules or masses, while 45% showed lung consolidations; 76% had accompanying micronodules, and 51% presented multiple lymphadenopathies. This typical CT pattern, particularly prevalent among HIV-positive patients (38%) who showed increased mediastinal lymphadenopathy, suggests distinguishing features in pseudotumoral TB.Sputum studies, performed in 55% of patients, yielded no positive results, indicating limited sensitivity in pseudotumoral presentations. Bronchial biopsy, bronchial aspiration, and CT-guided biopsy were the primary methods for definitive TB confirmation. Notably, diagnostic delays were more significant in non-HIV patients, suggesting that systematic bronchial biopsy or aspiration may be warranted in all patients with pulmonary masses from TB-endemic areas, regardless of HIV status. Following TB treatment, 70% of patients reported symptom resolution, and 48% showed partial or complete regression of the pseudotumoral mass. CONCLUSIONS: Our findings underscore the need to systematically include TB in the differential diagnosis of pulmonary masses in patients from TB-endemic regions, irrespective of HIV status or prior TB history. Radiologic findings of mass-like lesions with micronodules and lymphadenopathy, especially in non-HIV cases, should prompt consideration of bronchial biopsy when initial sputum results are negative. By minimizing diagnostic delays and supporting TB elimination efforts, these findings aim to reduce TB-related morbidity and mortality and prevent unnecessary invasive surgical procedures through earlier case detection in atypical presentations.