The blue man: a novel cutaneous manifestation of systemic amyloidosis.

Multiple cutaneous manifestations of amyloidosis have been described, and include periorbital purpura, plaques, nodules, and papules. Blue skin tint is not a previously described feature of cutaneous amyloidosis. We report the clinical case of a patient with known multiple myeloma and amyloidosis of the gastrointestinal tract who presented with progressive "blueness" of the skin. Dermatopathological examination and mass spectrometry of a skin biopsy specimen revealed the presence of subcutaneous amyloid light chain (AL) deposition. We believe this to be the first reported case of blue skin resulting from systemic amyloidosis.