In this paper, we present a rare disorder
which is known as corpora amylacea pulmonum. X-ray
CT scanning showed an abnormal focus of the lung as a
solitary mass with high density and spicular features
around the surface. The resected l u n ~ti ssue was - - U
characterized by the appearance of round, concentrically
laminated acellular bodies about 40-80 microns in
diameter. The bodies were usually found lying free in the
alveolar space and surrounded by the exudate alveolar
macrophages or multinuclear giant cells. Some of these
macrophages were in a state of progressive degeneration.
The bodies showed an affinity for Congo red and
exhibited partial birefringence. Moreover, al1 the bodies
had a strong positivity for the PAS reaction and anti
lysozyme antibodies. The exudate alveolar macrophages
and multinuclear giant cells also displayed reactivity for
PAS and lysozyme in a similar manner to that of the
bodies. Electron microscopically the bodies were
fundamentally composed of fibrillar elements, which
bore some resemblance to amyloid fibrils and probably
accounted for the partial affinity of the bodies for Congo
red. These amyloid-like fibrils were also found in the
cytoplasm of the macrophages. This suggested that the
concentrically laminated bodies in corpora amylacea
pulmonum might be formed by sequential aggregation,
fusion, coalescence and compaction of degenerated
alveolar macrophages