Metastatic pulmonary calcification mimicking pulmonary tuberculosis: A case report

Metastatic pulmonary calcification (MPC) is characterized by deposition of calcium in the normal lung parenchyma secondary to elevation of serum calcium. Most patients are asymptomatic and routine chest radiograph is not sensitive to make the diagnosis. Further imaging is needed such as computed tomography (CT) which typically shows small centrilobular nodules in the upper lobes. We report a case of a 30-year-old woman with end stage kidney disease who was diagnosed with pulmonary tuberculosis which was then revised to metastatic pulmonary calcification. The CT thorax feature for this patient was atypical for metastatic pulmonary calcification where it demonstrated tree-in-bud nodules suggestive of infection. The final diagnosis was made based on bronchoalveolar lavage which was culture-negative for Mycobacterium and transbronchial lung biopsy demonstrating calcium deposition in the interstitium.