Subacute cutaneous lupus erythematosus--the annular variant. A histological and ultrastructural study of five cases.

Subacute cutaneous lupus erythematosus is an uncommon, non-scarring variant of lupus erythematosus which has received scant attention in the pathology literature. Its recognition as a distinct entity is important, as, although mild systemic features may be associated, there is characteristically a relative absence of life-threatening renal or central nervous systemic involvement. Subacute cutaneous lupus erythematosus may be clinically sub-divided into the more common annular and the rarer papulosquamous (psoriasiform) variants. A clinicopathological study of five cases of the annular variant is presented with a review of the literature. We highlight the histological and ultrastructural appearances. Discriminatory features from the other variants of lupus erythematosus and additional conditions with which it may be confused, including lichen planus and acute graft-versus-host disease, are discussed.