Ultrastructural localization of amyloid P component in primary localized cutaneous amyloidosis

Amyloid P component (AP) was specifically localized to dermal amyloid deposits in the papular and nodular variants of primary localized cutaneous amyloidosis by an immunoperoxidase technique using an antibody to serum amyloid P component (SAP). Specific staining with anti‐SAP of elastic fibre microfibrils which has previously been observed in normal skin, was also present and was noted in close proximity 10 deposits of amyloid material. AP associated with normal elastic fibre microfibrils may be involved in the deposition of amyloid fibrils in vivo.