Pulmonary alveolar microlithiasis: report on 576 cases published in the literature

Pulmonary alveolar microlithiasis (PAM) is a rare disease characterized by intra-alveolar calcium deposits. The etiology of the disease is still unknown and many authors have supposed that an inherited local enzymatic defect is responsible for calcium deposition. The present paper aimed to study the disorder throughout the world, emphasizing the diagnostic and therapeutic views.

All the papers published on this subject in the literature were reviewed.

Cases studied were 576 and most of them came from Europe (42.7%) and Asia (40.6%). The countries involved were fifty-one and twelve of them were attributed with at least ten cases each (Bulgaria, France, Germany, India, Italy, Poland, Spain, Russia, Japan, Turkey, USA, ex-Yugoslavia). Symptoms were absent in more than half the patients; dyspnoea, cough and chest pain were reported in the other cases. Family history for the disease was found in one-third of the patients. Chest x-rays and computed tomography were so characteristic that they were enough to diagnose the disease even if microscopic evidence of the microliths into the alveoli was obtained in most cases (e.g. by biopsy, autopsy, bronchoalveolar lavage). Pulmonary tuberculosis or sarcoidosis were misdiagnosed in 88 cases out of the 576. The course of the disease was slow and patients usually died as a result of cardio-respiratory failure.

This review of PAM has shown that the etiology of the disease is still unknown, it is widespread throughout the world and easy to diagnose; it develops slowly and therapy is ineffective except for lung transplantation.