Nodular pulmonary amyloidosis. Description of a case with ultrastructure.

A 64-year-old man with a suspicious asymptomatic coin lesion received a thoracotomy that showed two foci of isolated nodular pulmonary amyloidosis. Ultrastructural analysis verified the amyloid nature of the lesion and suggested that the fibrils were produced by plasma cells and processed by macrophages. The pathogenesis of this lesion is discussed in light of recent studies.