Amyloidosis cutis dyschromica

Area of Science:

• Dermatology
• Histopathology
• Immunohistochemistry

Background:

• Amyloidosis cutis dyschromica is a rare variant of cutaneous amyloidosis, with only 26 cases previously reported.
• Understanding its clinical and histopathological features is crucial for diagnosis and management.

Purpose of the Study:

• To enhance clinical and histopathological data for amyloidosis cutis dyschromica.
• To detail the immunohistochemical profile of this rare condition.
• To review previously reported cases and consolidate knowledge.

Main Methods:

• Retrospective review of 10 patients diagnosed with amyloidosis cutis dyschromica at a single center.
• Documentation and analysis of clinical, histopathological, and immunohistochemical features.
• Review of existing literature on amyloidosis cutis dyschromica.

Main Results:

• Described 10 new cases (6 female), including familial and sporadic instances.
• Clinical presentation includes asymptomatic or mildly pruritic, generalized mottled hyper- and hypopigmented macules, often starting in childhood.
• Amyloid deposits in the papillary dermis stained positive with Congo red and expressed cytokeratins CK34βE12 and CK5/6.
• No systemic amyloidosis was observed in these patients.

Conclusions:

• This study presents the largest series of amyloidosis cutis dyschromica to date.
• The condition is a rare variant of primary cutaneous amyloidosis without systemic involvement.
• Immunohistochemical positivity for CK34βE12 and CK5/6 suggests keratinocyte origin of the amyloid deposits.