Discoid lupus erythematosus with secondary amyloidosis

Secondary localized cutaneous amyloidosis is a clinically unapparent phenomenon associated with various cutaneous pathologies, usually tumours of epidermal origin. The amyloid is thought to be derived from keratinocytes.

To characterize the amyloid deposition observed incidentally within lesional biopsies from three patients with discoid lupus erythematosus (DLE), and retrospectively to study the phenomenon within DLE skin samples.

Localized amyloid deposition was observed in three cases of DLE by immunofluorescence studies, and these cases were further studied by histology and immunohistochemistry using a monoclonal anticytokeratin antibody. Retrospective histological review of DLE tissue specimens archived over 12 months was performed to look for evidence of previously undetected amyloid.

Amyloid deposition was confirmed histologically in the three index cases by staining with Congo red and thioflavin T. Positive staining with an anticytokeratin antibody demonstrated the epidermal origin of the amyloid protein. Of the 18 archived cases reviewed amyloid was retrospectively detected in one sample.

Secondary cutaneous amyloidosis of keratinocyte origin can be seen in DLE lesions. It may be a not infrequent occurrence and may remain under-reported. We discuss the possible role of disease chronicity and colloid body degradation in the pathogenesis of amyloidosis.