Central spherules in pulmonary corpora amylacea.

Pulmonary corpora amylacea were found in 37 of 6,500 (0.6%) unselected autopsies. The patients had ranged in age from 48 to 87 years (average, 70). Among 1,000 corpora amylacea studied, there were 30 that contained centrally located, more or less intact, hollow spheres 15 to 20 mu in diameter. Morphologic considerations suggest that the spheres are derived from plant spores, and it is suggested that a possible origin is from inspired lycopodium spores, which are used as a dusting powder. Formation of pulmonary corpora amylacea as a reaction to lycopodium could account for the peculiar sporadic incidence of these bodies and their remarkable uniformity in size.