Primary pulmonary amyloidosis associated with multiple myeloma.

Amyloidosis is a syndrome characterized by the deposition of an insoluble proteinaceous material in the extracellular matrix of one or several organs. Respiratory tract involvement with amyloid is rare and deposition of lower respiratory tract has been recognized in a variety of situations with different presentations. Primary idiopathic amyloidosis may be a diagnostic problem because of its low incidence and its variable manifestations. We report herein a case with multiple myeloma presenting diffuse interstitial infiltration, in which pulmonary AL type amyloidosis was diagnosed through transbronchial lung biopsy.