Elastosis Amyloidosis as a Histologic Pattern in Cutaneous Amyloidosis

Area of Science:

• Dermatology
• Pathology
• Biochemistry

Background:

• Elastosis amyloidosis is an extremely rare cutaneous amyloidosis.
• Amyloid deposition occurs around dermal elastic fibers.
• Only 11 cases have been previously documented, some with systemic involvement.

Purpose of the Study:

• To report a novel case of elastosis amyloidosis.
• To characterize the specific type of amyloid deposit.
• To explore potential insights into the etiopathogenesis of amyloidosis.

Main Methods:

• Histopathological analysis of an umbilical nodule.
• Special staining (PAS, Congo red) for amyloid.
• Immunohistochemical staining for cytokeratins, light chains, and systemic amyloid markers.

Main Results:

• Amyloid deposits were found in the upper reticular dermis surrounding elastic fibers.
• Staining confirmed amyloid deposition.
• Immunohistochemistry revealed positivity for cytokeratins and negativity for light chains and systemic markers.
• Diagnosis of elastosis amyloidosis with amyloid-AK deposit, a previously unreported finding.

Conclusions:

• This case represents a unique instance of elastosis amyloidosis with amyloid-AK deposits.
• The findings may contribute to understanding the pathogenesis of localized and systemic amyloidosis.
• Further research into amyloid-AK is warranted.