Amyloidosis cutis dyschromica in two female siblings: cases report

BACKGROUND Cutaneous amyloidosis has been classified into primary cutaneous amyloidosis (PCA, OMIM #105250), secondary cutaneous amyloidosis and systemic cutaneous amyloidosis. PCA is the deposition of amyloid in previously apparent normal skin without systemic involvement. Amyloidosis cutis dyschromica (ACD) is a rare distinct type of PCA. Here, the unique clinical and histological findings of two Chinese female siblings with ACD were described. CASES PRESENTATIONS Patient 1 was a 34-year-old female, presented with mildly pruritic, diffuse mottled hyperpigmentation and hypopigmentation. The lesions involved all over the body since she was 10 years old. There were a few itchy blisters appearing on her arms, lower legs and truck, especially on the sun-exposed areas in summer. Some hypopigmented macules presented with slight atrophy. Patient 2 was 39-year-old, the elder sister of patient 1. She had similar skin lesions since the same age as the former. The atrophy and blisters on the skin of the patient with amyloidosis cutis dyschromica have not been described in previous literature. Histological examinations of the skin biopsies taken from both patients revealed amyloid deposits in the whole papillary dermis. Depending on the histological assessment, the two cases were diagnosed as amyloidosis cutis dyschromica. CONCLUSION The two cases suggest that the atrophy and blisters may be the uncommon manifestations of amyloidosis cutis dyschromica. It alerts clinicians to consider the possibility of ACD when meeting patients with cutaneous dyschromia. Skin biopsy is essential and family consultation of genetic investigation is very important in such cases.