Extensive haemorrhagic-bullous skin manifestation of systemic AA-amyloidosis associated with IgGlambda-myeloma

In an 86-year-old woman with a multiple myeloma of the IgG lambda subtype a coinciding systemic amyloidosis manifested as a macroglossia, diffuse alopecia and generalized cutaneous involvement. The skin was affected by milium-like papules, petechial haemorrhages and an increased tissue fragility with subsequent blister formation. The typical histology and immunohistology pattern revealed large intradermal amyloid masses, reacting positively with anti-amyloid A antibodies, which surrounded cuff-like dilatated blood capillaries. The abundance of these amyloid deposits led to significant deflexibilization and fragility of the capillaries and the dermal matrix eventually resulting in the haemorrhagic-bullous eruptions. The peculiar feature of the present case is the intensity of bullous-haemorrhagic skin damage due to amyloid A deposition without any detection of cutaneous IgGl as the myeloma-derived paraprotein assumed to be causative for the development of systemic AA amyloidosis.