The Combination of Pulmonary Alveolar Microlithiasis and Pneumoconiosis – A Clinical Case

Abstract

Pulmonary alveolar microlithiasis is a rare genetic disease characterized by the formation of intraalveolar calcium phosphate microliths. Clinical and radiological manifestations are similar to pneumoconiosis, which makes it difficult to diagnose a comorbid condition. This article presents a case from clinical practice: a 30-year-old male patient, non-smoker was referred to a occupational pathology center with a preliminary diagnosis of pneumoconiosis. He worked for 8 years under conditions of exposure to highly fibrogenic dust with the maximum allowable concentrations in the air of the working area exceeding by 2.3–2.1 times. During this period, preliminary and 3 periodic medical examinations were carried out which did not reveal any contraindications for continuing work. Examination at the center of occupational pathologists revealed signs of respiratory failure of the 2nd degree, severe pulmonary hypertension and radiological diffuse dissemination syndrome with small shading of two types - a large number of high (calcium) density foci with clear edges and a moderate number of medium density foci. Histological examination revealed signs of pulmonary fibrosis and interstitial inflammation of the type of nonspecific interstitial pneumonia, microliths located intraalveolarly, as well as a small amount of granulomas with hyalinosis in the center, a concentric arrangement of collagen fibers, fibroblasts, alveolar macrophages. A comorbid disease was diagnosed – pulmonary alveolar microlithiasis in combination with pneumoconiosis confirmed by the results of genetic testing – the c.1328delT mutation of the SLC34A2 gene was detected. The further course of the disease was characterized by progression of dyspnea and desaturation, an increase in the number of high-density foci in the lungs. 2 years after diagnosis – death due to respiratory failure. The presented case demonstrates the possibility of a combination of pulmonary alveolar microlithiasis with pneumoconiosis and an unfavorable prognosis of a comorbid disease.