Late-onset amyloidosis cutis dyschromica: an unusual case.

Amyloidosis cutis dyschromica (ACD) is a rare form of primary cutaneous amyloidosis. ACD, first described by Morishima in 1970 is characterized by (i) macular, speckled, reticular hyperpigmentation with hypopigmented spots distributed extensively over the body; (ii) little or no pruritus; (iii) prepubertal onset; and (iv) focal subepidermal amyloid deposition. A 49-year-old woman presented with a 20-year history of progressive, asymptomatic, generalized mottled hyper- and hypopigmented macules all over the body. Histopathological examination of a punch biopsy specimen showed deposition of homogeneous, eosinophilic material in the papillary dermis. This amorphous, eosinophilic material was stained metachromatically with crystal violet stain and found to be compatible with amyloid. Based on the clinical and histopathological findings, the patient was diagnosed as having ACD. Amyloidosis cutis dyschromica must be considered in the differential diagnosis of patients with diffuse dyschromatosis including both hyperpigmented and hypopigmented lesions and histopathological confirmation is necessary in order to reach a correct diagnosis.