An Interesting Case of Mixed Dust Pneumoconiosis With Progressive Massive Fibrosis and Cor Pulmonale in a South American Farmer

Pneumoconiosis is an occupational disease found in workers with environmental exposure to organic and inorganic dust, as in mining, sandblasting, pottery, stone masonry, and farming. The inflammatory response of the lung to respirable dust causes the formation of macules, nodules, and fibrosis, and higher silica content in inhaled dust is associated with increased fibrosis. Mixed dust pneumoconiosis (MDP) is characterized by exposure to dust containing 10-20% silica, and its lung imaging show irregular opacities. Histopathology plays a vital role in the diagnosis of MDP. Though it has a favorable outcome, it evolves slowly over many years of constant exposure and is characterized by worsening dyspnea and cough gradually progressing to cor pulmonale. The only effective treatment is removing exposure, which makes it essential to recognize the disease early for a favorable outcome. We present a case of mixed dust pneumoconiosis in a farmer from South America who had asthma. He presented with worsening dyspnea and multiple nodules in both lungs on imaging and cor pulmonale. An extensive workup was done, and it ruled out any malignancy and tuberculosis. Analysis of video-assisted thoracoscopic surgery (VATS) biopsy samples confirmed the diagnosis of mixed dust pneumoconiosis. He had a confluence of irregular nodes in the upper lobes of the lungs, and the largest was 2.1 cm. This fits the International Labour Organization (ILO) definition of progressive massive fibrosis. This, along with cor pulmonale present in him, gives it a poor prognosis even after he is removed from dust exposure. He received steroids, which led to symptomatic improvement, and he was discharged to follow up with the pulmonologist.