The Cutaneous Amyloidoses

Abstract

Thirty-nine examples of primary localized cutaneous amyloidosis were studied. In lichen amyloidosus, characteristic manifestations were pruritic papules on the lower extremities and deposits of amyloid limited to the papillary corium. Crystal violet was the most reliable preparation for amyloid. In autopsy material, amyloid was not found in extracutaneous sites. No patient with systemic amyloidosis had the clinicopathologic findings of lichen amyloidosus. Thus, when lichen amyloidosus is recognized, investigation for systemic disease is not indicated. In macular amyloidosis, the lower extremities were the common site of involvement, pruritus was frequent, and deposits of amyloid were limited to the dermal papillae. In the tumefactive form of primary localized cutaneous amyloidosis lesions were found on the extremities, trunk, genitals, or face. The histologic picture resembled that found in cutaneous lesions of primary systemic amyloidosis. The electron microscopic appearance of the amyloid deposits was similar to that found in other forms of cutaneous amyloidosis. Clinically insignificant microdeposits of secondary localized cutaneous amyloidosis were observed in a variety of disorders, including seborrheic keratoses and Bowen's disease. The high incidence of amyloid deposits reported by others in pilomatrixomas and cylindromas was not confirmed.