Microscopy: Two tan tissue fragments 5mm & 9mm.
Microscopy: The biopsy consists of bronchial mucosa with subepithelial deposition of an amorphous eosinophilic material that stains positively with Congo red. There is no malignancy.
Immunoperoxidase stains show that the amyloid is strongly positive for kappa light chain. There is some weak staining for transthyretin, of doubtful significance. Lambda light chain and amyloid A stains are negative.
These findings indicate amyloidosis of light chain (AL) type. This result needs to be interpreted in the context of clinical findings and other investigations.
Conclusion: Right main bronchus biopsy: Amyloidosis.