LAUSR

To the Editor: Cutaneous amyloidosis can be secondary to many causes. We describe a case of amyloidosis that was secondary to the deposition of an antiretroviral drug enfuvirtide and clinically presented as bullae over the anterior abdominal wall. A 65-year-old man with HIV presented with pink vesicles and flaccid bullae on the anterolateral aspect of the lower abdomen (Figure 1) in areas of self-administered subcutaneous injections of enfuvirtide. He reported tissue swelling with a yellow discoloration immediately after injections that would spontaneously subside after a few minutes. A biopsy from the left lateral abdomen revealed dilated vessels concentrically encompassed by pink globular material and nodular collections of the pink amorphous substance in the upper dermis (Figure 2), which was accompanied by a sparse, perivascular, lymphohistiocytic inflammatory infiltrate; scattered plasma cells; and rare eosinophils in a background of dermal edema. Although Congo red stain was negative, crystal violet revealed metachromatic staining of the globular material that was highlighted as dark violet against a blue background. Given these clinical and histopathologic findings, a diagnosis of drug-induced amyloidosis was made. Amyloidosis refers to a group of disorders that result from misfolding of proteins in the characteristic betapleated sheet structure that can accumulate in various tissues. There are different subtypes of amyloidosis based on the type of protein deposited: immunoglobulin light chain protein (AL); serum amyloid A (AA), an acute-phase reactant accumulating in those with longstanding inflammatory conditions; beta-2 microglobulin (Ab2M) in patients with renal failure; keratin in macular and lichen amyloidosis; pharmaceutical-derived amyloid (eg, enfuvirtide, injectable insulin); and mutated proteins in hereditary amyloidosis such as transthyretin.1 Other familial forms include genetic variants of apolipolipoprotein AII (AApoAI, AApoAII), fibrinogen A alpha chain (AFib), lysozyme (ALys), cystatin C (ACys), and gelsolin (AGel).2 Enfuvirtide-Induced Cutaneous Amyloidosis