A very rare pulmonary pathology from symptom to diagnosis: Dendriform pulmonary ossification

Abstract

: Pulmonary ossification is an uncommon, chronic, and progressive lung disease characterized by the presence of mature bone within the lung parenchyma. Diagnosis during life is rare; most cases are detected incidentally during autopsies. Chronic interstitial inflammation typically occurs in the lungs. This often leads to fibrosis in the parenchyma, though it can sometimes be idiopathic. Dendriform pulmonary ossification (DPO) can be classified as either idiopathic or secondary to an existing lung disease. Even though most patients are diagnosed through autopsy series, we present our case diagnosed using a videothoracoscopic wedge resection. A 49-year-old male patient, who has no chronic diseases and has never smoked, worked in aluminum casting for nine years, approxiately a decade ago. He visited the chest diseases clinic with complaints of increasing chest pain and shortness of breath over the past year. Physical examination revealed rales in the bilateral lung bases, but no clubbing. His oxygen saturation was 98%. Reticulonodular patterns were noted in all zones of both hemithoraces on a chest X-ray. The thorax Computed Tomography (CT) showed milimetric punctate calcific diffuse nodular and septal thickenings accompanied by pleuroparenchymal bands in both lungs. The patient, whose pulmonary function test was limited, was started on a therapeutic dose of 32 mg prednol. Gas exchange was reassessed with Diffusing Capacity of the Lung for Carbon Monoxide (DLCO) after two weeks. A diagnostic biportal videotho-racoscopic wedge resection was performed on the patient. Due to the tough nature of the lung tissue, two staples broke during the operation. The patient was discharged on the second post-operative day with a pathology report confirming dendriform pulmonary ossification. The patient’s outpatient follow-up is ongoing. DPO is most often diagnosed from surgical samples or during autopsies. It is a rare lung pathology characterized by the presence of mature bone tissue within the lung parenchyma. The disease frequently arises secondary to an underlying lung condition. Chronic inflammation is believed to play a role in its etiology. As seen in our patient’s case, professions like aluminum casting can also cause chronic lung inflammation, potentially leading to DPO.