A female infant had histiocytosis X confined to the lungs. There was no evidence of involvement of other organs clinically, radiologically, or at postmortem examination at the age of 12 months. She showed severe failure to thrive but had no respiratory manifestations.
Aftimos S, Nassar V, Najjar S. Primary Pulmonary Histiocytosis in an Infant. Am J Dis Child. 1974;128(6):851-852. doi:10.1001/archpedi.1974.02110310099020