Primary localized cutaneous amyloidosis refers to a group of disorders characterized by deposition of amyloid in the dermis without any systemic involvement. It comprises the following clinical types: macular, lichenoid, nodular, and biphasic. There are also rare variants such as amyloidosis cutis dyscromica and poikiloderma-like cutaneous amyloidosis. We report a case of primary cutaneous amyloidosis in a 17-year-old boy with unusual pigmentation of various patterns (reticulate and diffuse pigmentation with mottling and rippling at places) and hypopigmented atrophic macules. Our patient also had nail, oral, and mucosal pigmentation that have not been described. Amyloid deposits were shown histopathologically in both hyperpigmented and hypopigmented macules.

Primary amyloidosis is caused by a monoclonal proliferation of plasma cells and is capable of producing cutaneous lesions. A 56-year-old male was admitted to the hospital for evaluation of chronic back pain and acute lower extremity weakness. On examination, he was noted to have subungual verrucous plaques with overlying nail dystrophy on his bilateral thumbs. A biopsy of one subungual lesion showed a deposition of amorphous material in the dermis that stained with Congo red and crystal violet. These cutaneous lesions ultimately led to the diagnosis of plasma cell dyscrasia and primary amyloidosis. Based on the literature search, primary amyloidosis presenting with this degree of subungual thickening and overlying nail dystrophy has not been previously reported.