Pulmonary alveolar microlithiasis: A case report with a novel mutation in the SLC34A2 gene and review of the literature

A Rare Case of Pulmonary Alveolar Microlithiasis with Diffuse Lung Uptake on Bone Scintigraphy

Pulmonary alveolar microlithiasis is a rare disease characterized by accumulating intraalveolar small calcium phosphate stones. The disease is slow and does not show any signs in the early stages, but the shortness of breath, cough, and right heart failure may develop as it progresses. Methylene diphosphonate used in bone scintigraphy shows high uptake of calcium deposits in the alveoli and causes diffuse increased radiopharmaceutical uptake in the lungs.

Pulmonary alveolar microlithiasis: no longer in the stone age

Pulmonary alveolar microlithiasis (PAM) is a rare parenchymal lung disease caused by variants in the SCL34A2 gene and characterised by the accumulation of intra-alveolar microliths. PAM has been reported in fewer than 1100 cases throughout the world. It is an autosomal recessive hereditary disease and often associated with consanguinity. Progress with respect to the genetic background and pathophysiology has resulted in an increased understanding of the disease in recent years. Until now, 30 genetic different SLC34A2 variants have been reported, which all are considered significant for disease development. There is no sex difference and the majority of cases are diagnosed at the age of 30–40 years. Many patients are asymptomatic and the diagnosis is made at random. When symptomatic, dyspnoea, cough, chest pain and fatigue are common complaints. The diagnosis of PAM can confidently be based on typical radiographic findings and genetic testing proving rare biallelic SCL34A2 gene variants. Bronchoalveolar lavage and histopathology may show microliths. There is no disease-specific treatment and management is supportive. Lung transplantation should be considered in advanced cases.

Pulmonary alveolar microlithiasis is a rare, autosomal recessive lung disease. Formation of alveolar microliths is caused by SCL34A2 variants. The prognosis is severe; respiratory failure is common. Lung transplantation is the only effective therapy.https://bit.ly/3dpkbRw