Pulmonary Alveolar Microlithiasis - Chest X Ray

A 39 years old female came to radiology department for X-ray chest with history of dyspnea on exertion. The X ray is shown as below:

Radiological Findings on the X ray Chest: X-ray chest (in the picture above) shows that the lung fields are diffusely occupied by discrete high density opacities resembling grains of sands. In spite of
superimposition or summations of shadows the individual deposits are identifiable and measure about a 1 mm in diameter thick and streaky. The opacity appears confluent showing the lungs as almost white with obliteration of the mediastinal and diaphragmatic contours and pulmonary vascular marking are indistinct. The density is greater over the lower than the upper zone.

Comments and Explanation: The characteristic finding on the chest radiograph is that of a fine, dense stippling. This is a well-defined, nodular infiltrate which involves both lungs, and may be so extensive as to cause opaque lungs with relative lucency of the mediastinal structures, diaphragm and pleura. There is widespread parenchymal calcification.
In addition to the finding seen, other findings that may be seen include bullae in the lung apices, a zone of increased lucency between lung parenchyma and the ribs (a black pleural line) and pleural calcification.
In some patients concentration of the nodules in subpleural, para septal and peribronchiolar alveoli can produce linear strands of calcification parallel to or perpendicular to the pleural surface.


Opinion: Pulmonary alveolar microlithiasis

Clinical Discussion: The cause of pulmonary alveolar microlithiasis is unknown, and majorities
are diagnosed between the ages of 30–50 years. There is no sex predominance. The disease exhibits a strong familial tendency. Most patients are asymptomatic. When the patient is symptomatic, most common symptom is dyspnea on exertion. Non productive cough and hemoptysis develops in some patients. There are often no physical signs in the chest even when the radiography is grossly abnormal, later there may be inspiratory crepitation and ultimately the signs of cor-pulmonale. Biopsy shows calcified spherules filling alveolar spaces. The spherules have a concentric lamelleted appearance suggesting that they grow by the addition of successive layers. The spherules contain both calcium and phosphorus. Deposits of calcium phosphate measuring 0.1 to 0.3 mm in size are found in the alveoli. It is a chronic disease without evidence of clinical abnormality until an advanced stage, when right heart failure may result from pulmonary fibrosis.