Primary pulmonary leiomyosarcoma in a patient with disseminated pulmonary tuberculosis and constrictive pericarditis

Primary pulmonary leiomyosarcoma (PPL) is an exceedingly rare malignancy, accounting for fewer than 0.5% of all lung tumours. Its occurrence alongside disseminated tuberculosis (TB) complicated by constrictive pericarditis has not previously been described. We report a 66-year-old HIV-negative male from rural South Africa presenting with progressive dyspnoea, found to have a right upper lobe nodule that enlarged despite adequate anti-TB therapy. Computed tomography (CT)-guided biopsy demonstrated spindle cell morphology. Cardiac MRI and right and left heart catheterisation confirmed constrictive pericarditis with severely impaired right ventricular function, precluding immediate lobectomy. A staged surgical approach was employed: anterior pericardiectomy via median sternotomy was performed first in attempt to optimise right ventricular function, followed by open right upper lobectomy. Histopathological analysis and immunohistochemistry confirmed PPL (FNLCC Grade 3, pT3N0M0) with R0 resection margins. All sampled nodal stations were free of malignancy, and whole-body positron emission tomography-CT (PET-CT) excluded nodal involvement and distant metastatic disease. The patient was discharged on postoperative day six and remained ECOG performance status 1 at 10-month follow up. This case illustrates that in TB-endemic regions, a lung nodule enlarging on adequate anti-TB therapy should prompt tissue diagnosis irrespective of an established alternative diagnosis. It further highlights the importance of a staged surgical approach when concomitant cardiac pathology compromises right ventricular function, acknowledging rapid tumour growth progression during the inter-procedural recovery interval.