[Pulmonary nodular amyloidosis].

Amyloidosis is a systemic disease caused by extracellular accumulation of amyloid in different parts of the body. Pulmonary involvement is infrequent and nodular amyloidosis is extremely rare. We present the case of a 72-year-old man with chronic obstructive pulmonary disease in whom a 3-cm pulmonary nodule was discovered during routine radiological follow-up. After various complementary investigations failed to identify the etiology of the nodule, surgical excision was performed. Subsequent histopathological study revealed the presence of amyloid deposits with characteristic apple-green birefringence when stained with Congo-red under polarized light microscopy.