Abstract

A 50-year-old Caucasian man with a history of AL amyloidosis presented to dermatology clinic for evaluation of progressive skin laxity and comedones. The patient had amyloidosis noted in the endomyocardium, and bone marrow biopsy showed plasma cell neoplasm (10-15% cellularity). Histologic examination of the skin showed an attenuated epidermis flanking markedly dilated follicular infundibula with conspicuous keratinous plugs containing multiple hair shafts. The underlying papillary dermis demonstrated artifactual fragmentation and a scant perifollicular lymphohistiocytic inflammatory infiltrate. A VVG stain displayed marked decrease in elastic fibers within the papillary dermis. The reticular dermis showed elastic fibers fragmentation and thickening combined with clustering around the dermal adnexal structures and nerves. A Congo red stain was negative. A colloidal iron stain showed no significant increase in interstitial mucin. Skin biopsies prior to AL amyloidosis diagnosis showed elastic fiber abnormalities without amyloid. While the exact pathogenesis of acquired cutis laxa is not established, there are case reports showing evidence of amyloid deposition associated with reduction and fragmentation of elastic fibers in the setting of myeloma, establishing the basis for the hypothesis for cell-mediated destruction of elastic fibers in gammopathy-associated cases of cutis laxa. There are few cases describing acquired cutis laxa in the setting of monoclonal gammopathy, and exceedingly fewer cases related to systemic amyloidosis. However, the histological findings in our patient are consistent with those previously described in the literature, most notably with accumulation of dystrophic, fragmented elastic fibers, and negative Congo red staining in the skin, despite amyloid identified in other organs.