title: Primary systemic (amyloid light-chain) amyloidosis masquerading as pseudoxanthoma elasticum: recognizing a novel clinicopathological pattern.
abstract: OBJECTIVE
  Primary systemic (amyloid light-chain [AL]) amyloidosis has a variety of cutaneous manifestations. In this case, we present a novel clinicopathological pattern of AL amyloidosis.
  
  
  METHODS
  A woman in her 50s with a history of AL amyloidosis manifesting as macroglossia and bilateral carpal tunnel syndrome presented with skin-colored to yellow cobblestoned plaques to the neck and bilateral antecubital fossa. Although clinical similar to pseudoxanthoma elasticum (PXE), the skin changes were found to be due to amyloid deposition primarily around the pilosebaceous unit but also within the papillary and reticular dermis. Previous reports of PXE-like plaques in AL amyloidosis have been reported as part of a very rare entity termed amyloid elastosis. However, our case demonstrates several important clinical and pathological differences from this entity. Most notably, there was no dermal elastic fiber involvement, limited cutaneous and systemic involvement, and a fairly indolent course with better response to treatment.
  
  
  CONCLUSIONS
  Identification of this atypical presentation of AL amyloidosis has important implications for early detection and rapid treatment. The lack of elastic fiber involvement establishes the uniqueness of this case, and further study may be required to determine if this histological finding has prognostic significance.
authors.affiliation: Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Heidi
authors.initials: H
authors.lastname: Wat
authors.affiliation: Division of Dermatology, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Wu
authors.affiliation: Division of Anatomical Pathology, Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Muhammad N
authors.initials: MN
authors.lastname: Mahmood
authors.affiliation: Division of Dermatology, Department of Medicine, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Alain
authors.initials: A
authors.lastname: Brassard
mesh_terms: D000686:Amyloidosis / Q000175:diagnosis* / Q000473:pathology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D000075363:Immunoglobulin Light-chain Amyloidosis; D008875:Middle Aged; D011561:Pseudoxanthoma Elasticum / Q000175:diagnosis* / Q000473:pathology