Primary Localized Cutaneous Nodular Amyloidosis in the Absence of Systemic Disease

A 41-year-old man presented with an asymptomatic, slowly enlarging plaque on the lower aspect of his left cheek, present for approximately 4 months. His past medical history was remarkable for allergic rhinitis. Three years before, he had had a nearly identical lesion surgically excised by Mohs method at the same site. On examination, there was a waxy, yellowish plaque, measuring 2.1 cm × 1.0 cm on the left cheek in proximity to the oral commissure (Figure 1). A shave biopsy revealed an atrophic epidermis with nodular aggregates of eosinophilic material in the dermis (Figure 2). Higher magnification showed an inflammatory infiltrate composed largely of plasma cells, which stained positively for CD20 and κ light chains (Figure 3). Congo red staining confirmed the diagnosis of nodular amyloidosis (Figure 4).