Cutaneous manifestations of lupus erythematosus: a practical clinicopathological review for pathologists

Accurate diagnosis of connective tissue diseases is often challenging, and relies upon careful correlation between clinical and histopathological features, direct immunofluorescence studies and laboratory work-up. Lupus erythematosus (LE) is a prototype of connective tissue disease with a variety of cutaneous and systemic manifestations. Microscopically, cutaneous LE is classically characterised by an interface dermatitis although other histopathological patterns also exist, depending upon the clinical presentation, location and chronicity of the skin lesions. In this article, we review the clinical, serological, histopathological and direct immunofluorescence findings in LE-specific and LE non-specific skin lesions, with an emphasis upon lesser-known variants, newly described features and helpful ancillary studies. This review will guide general pathologists and dermatopathologists in accurately diagnosing and subclassifying cutaneous LE.