obsolete_amyloidosis cutis dyschromia true Replaced with Mondo term. A primary amyloidosis characterized by localized cutaneous amyloid deposition. This condition usually presents with itching (especially on the lower legs) and visible changes of skin hyperpigmentation and thickening that may be exacerbated by chronic scratching and rubbing. Primary localized cutaneous amyloidosis is often divided into macular and lichen subtypes although many affected individuals often show both variants coexisting. Lichen amyloidosis characteristically presents as a pruritic eruption of grouped hyperkeratotic papules with a predilection for the shins, calves, ankles and dorsa of feet and thighs. Papules may coalesce to form hyperkeratotic plaques that can resemble lichen planus, lichen simplex or nodular prurigo. Macular amyloidosis is characterized by small pigmented macules that may merge to produce macular hyperpigmentation, sometimes with a reticulate or rippled pattern. In macular and lichen amyloidosis, amyloid is deposited in the papillary dermis in association with grouped colloid bodies, thought to represent degenerate basal keratinocytes. The amyloid deposits probably reflect a combination of degenerate keratin filaments, serum amyloid P component, and deposition of immunoglobulins. PLCA3 inheritance is autosomal recessive. Amyloidosis cutis dyschromia is a rare primary cutaneous amyloidosis characterized by macular or reticulate hyperpigmentation with symmetrically distributed guttate hypo- and hyperpigmented lesions which progress gradually over the years to involve almost the entire body (with relative sparing of the face, hands, feet and neck). Patients are usually asymptomatic, however mild pruritus may be associated. Amyloid deposition in the papillary dermis is observed on skin biopsy. Systemic amyloidosis is not present and association with generalized morphea, atypical Parkinsonism, spasticity, motor weakness or colon carcinoma is rare. [Orphanet_319635] OMIM:617920 http://purl.obolibrary.org/obo/MONDO_0017906 3.41.0 amyloidosis cutis dyschromica