Pulmonary alveolar microlithiasis: Incidental finding - should we Ignore?

Area of Science:

• Pulmonary Medicine
• Pathology
• Genetics

Background:

• Pulmonary alveolar microlithiasis (PAM) is a rare autosomal recessive disorder.
• Mutations in the solute carrier family 34 member 2 gene are implicated in PAM.
• PAM often presents as an incidental finding during medical examinations.

Observation:

• A retrospective autopsy study identified PAM in two patients with micronodular hepatic cirrhosis.
• Microscopic analysis revealed three forms of round hyaline bodies with specific staining characteristics.
• These microliths exhibited PAS positivity, von Kossa staining, and light green birefringence with Congo red.

Findings:

• The study identified characteristic morphological and staining features of pulmonary microliths.
• Retrospective analysis of 212 autopsies highlighted the incidental detection rate of PAM.
• Distinctive birefringence patterns differentiate PAM from amyloid deposition.

Implications:

• Increased awareness of PAM's incidental nature can improve early diagnosis.
• Understanding the pathophysiology may lead to targeted therapies, such as hydroxyapatite crystal growth inhibitors.
• Family screening and regular imaging are recommended for individuals with PAM.