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Macular amyloidosis
Other Resources UpToDate PubMed

Macular amyloidosis

Contributors: Jeffrey M. Cohen MD, Laurie Good MD, Belinda Tan MD, PhD, Whitney A. High MD, JD, MEng, Susan Burgin MD
Other Resources UpToDate PubMed

Synopsis

Macular amyloidosis (MA) is a form of primary cutaneous amyloidosis (a category which also includes lichen and nodular amyloidosis, poikiloderma-like cutaneous amyloidosis, primary cutaneous amyloidosis of the auricular concha, and the exceedingly rare entity of amyloidosis cutis dyschromica). In MA, a proteinaceous material, amyloid, which is derived from keratinocytes, is deposited in the superficial dermis without involvement of other tissue.

While the cause of MA is incompletely understood, it is associated with, and probably caused by, friction and scratching with fingernails or implements such as towels or brushes.

Clinically, MA manifests as hyperpigmentation. The most common locations are the upper back and extensor upper extremities. A rippled pattern is sometimes seen. MA and lichen amyloidosis (LA) are believed to exist on a spectrum and are mainly differentiated by the nature of the primary lesion (macules and patches in MA and thin plaques in LA) and histopathologic findings. Some patients also display features of both MA and LA, which is termed "biphasic amyloidosis."

MA is generally a pruritic condition, but it may sometimes be asymptomatic. MA has been described in the setting of connective tissue diseases, primary biliary cholangitis, and multiple endocrine neoplasia type 2a.

Codes

ICD10CM:
E85.9 – Amyloidosis, unspecified

SNOMEDCT:
111032003 – Macular cutaneous amyloidosis

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Last Reviewed:01/05/2020
Last Updated:05/11/2020
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Macular amyloidosis
A medical illustration showing key findings of Macular amyloidosis : Extensor distribution, Upper arm, Upper back, Pruritus, Hyperpigmented macules
Clinical image of Macular amyloidosis - imageId=5623260. Click to open in gallery.  caption: 'A close-up of confluent light brown macules forming a patch with a faint rippled appearance on the upper chest.'
A close-up of confluent light brown macules forming a patch with a faint rippled appearance on the upper chest.
Copyright © 2024 VisualDx®. All rights reserved.