Mycobacterium tuberculosis presenting as chest wall spindle cell neoplasm in an immunocompetent patient

Background Mycobacterial spindle cell pseudotumor is a rare benign condition that is characterized by spindle-shaped histiocytes containing acid-fast mycobacteria. It is more common in immunocompromised individuals, particularly those with HIV, or those receiving immunosuppression. Case presentation: We present here a case of a 32-year-old immunocompetent male with tubercular spindle cell neoplasms (SCN) involving chest wall, a rarely documented manifestation of Mycobacterium tuberculosis . The patient initially presented with cough and fever, and later developed cystic swellings over the chest wall. Despite repeated negative sputum AFB and CBNAAT results, imaging studies revealed two ill-defined cystic lesions over the chest wall growing inward with associated rib erosions and a lesion in the right upper lobe of the lung pointing toward a Koch’s etiology. Histopathology suggested a SCN, but CBNAAT from cyst aspirate confirmed Mycobacterium tuberculosis . The patient responded well to standard antitubercular therapy, achieving resolution of the symptoms without the need for surgery. Conclusion The case brings the spotlight to the extremely varied presentation of tuberculosis (TB), in our case, as SCN, often posing for significant diagnostic challenge, consequently delay. We recommend consideration of TB as a rare etiological differential diagnosis of SCN even in immunocompetent patients, given the relatively easier treatment to resolution, considering the endemicity of Tuberculosis in the Indian subcontinent.