Bullous Amyloidosis Masquerading as Pseudoporphyria.

Amyloidosis is not a singular disease but describes a group of diseases that result from abnormalities in protein folding and metabolism, leading to β-sheet polymers and amyloid fibrils. Cutaneous involvement is common and may occur as a primary disorder or secondary to systemic disease. Bullous skin changes, however, are rare occurrences in cutaneous amyloidosis. Bullous amyloidosis presents with characteristic histopathologic, immunohistochemical, and immunofluorescence patterns, all of which allow for careful distinction from other similar diseases. Importantly, bullous amyloidosis should prompt consideration of an underlying diagnosis of a lymphoproliferative disorder. We present the case of a woman who was diagnosed with bullous amyloidosis due to multiple myeloma after an extensive workup initially suggested other bullous diseases. We highlight the importance of recognizing this rare entity to prevent delay in diagnosis and management of its underlying cause.