Pulmonary Alveolar Microlithiasis; a Report of Two Youngest Cases in a Family.

is a rare disease; not more than 60 cases have been reported in the world literature. The essential features of this disease are: (1) a characteristic radiologic appearance of miliary disseminated lesions caused by innumerable intra-alveolar concrements throughout the lungs; (2) extremely few clinical symptoms until the late stage of disease, in contrast to the pronounced degree of radiologic and pathologic changes, and (3) frequent occurrence of more than one case in a single family. There seems no sexual predominance and most patients have been found between 30 and 50 years of age. The etiology of this condition remains obscure, although many acquired or environmental factors, as well as hereditary congenital predisposition, have been suggested. We have recently encountered two cases of pulmonary alveolar microlithiasis in a family. It is worthwhile adding these cases to the world literature in view of the fact they are siblings and are the youngest cases so far reported. One was eight years of age at the time of diagnosis, but a chest x-ray film taken at two years and ten months has, in retrospect, been recognized as showing the same characteristic pattern, although to a much lesser degree. The other, his younger sister and found by family examination, was four years and four months of age. In our opinion, these cases cannot be ignored whenever the etiology of this disease is to be discussed.