Persistent Hyperpigmented Macules on the Scalp and Face: Answer

Cutaneous AL amyloidosis is characterized by the deposition of AL amyloid or amyloid-like proteins in the dermis and subcutis. This rare entity predominantly affects adults with a mean age of 65 years. Cutaneous AL amyloidosis is derived from immunoglobulins produced by plasma cells and distinguished by the deposition of lambda lightchain amyloid, in contrast to other subtypes of primary cutaneous amyloidosis (PCA) that originate from cytokeratin. Although the pathogenesis of cutaneous AL amyloidosis is unknown, there have been reports of cutaneous amyloidosis emerging after local trauma or in the presence of immune dysregulation.