Amyloid-like pulmonary nodules, including localized light-chain deposition: clinicopathologic analysis of three cases.

Amyloid-like pulmonary nodules have been described in patients with systemic light-chain deposition disease, but their significance in other clinical contexts is unknown. We examined biopsy specimens of amyloid-like pulmonary nodules from 3 women without systemic light-chain deposition disease. Patient 1 (aged 62 years) had multiple pulmonary nodules and underwent 2 separate lung biopsies, the first showing nodules composed of kappa light-chain deposits accompanied by low-grade lymphoplasmacytic lymphoma limited to the lung and the second, obtained after chemotherapy 9 months later, showing only residual nodules without persistent lymphoma. Patients 2 (aged 65 years) and 3 (aged 69 years) had asymptomatic solitary pulmonary nodules. In all cases, electron microscopic examination showed dense granular extracellular deposits without the fibrillary characteristics of amyloid. Amyloid-like nodules should be distinguished from nodular amyloidosis and, in some patients, might represent a localized form of light-chain deposition.