Immunohistochemistry stains are positive for cytokeratin. Nodular cutaneous amyloidosis often presents with facial involvement. Biopsies demonstrate amyloid deposits throughout the dermis and immunohistochemistry is negative for cytokeratin and positive for lambda and or kappa light chains. NCA is a rare condition with fewer than fifty reported cases in the World's literature. It usually occurs in the sixth and seventh decades of life.
Lesions typically involve the face, scalp, and intertriginous regions.
Lesions usually consist of one or two isolated tumefactive, purpuric plaques which can be waxy appearing and variable in color and size. NCA progression to systemic disease has been estimated to occur in fifteen to fifty percent of patients. The problem with using a diagnosis of NCA for this patient was that her lesions did not consist of the typical isolated tumefactive nodules and plaques. The pattern of her lesions were more consistent with systemic amyloidosis, and since she ultimately developed systemic involvement, a diagnosis of systemic amyloidosis was entertained. Systemic amyloidosis is a rare disorder which usually occurs in aged persons and has a poor prognosis.