Pathology of discoid lupus erythematosus

Introduction

Discoid Lupus erythematosus (DLE) is the most common form of cutaneous lupus erythematosus. It is classified as located, affecting only the skin on the neck, or generalized, affecting above and below the neck. Risk of systemic Lupus erythematosus is approximately 5%. Lesions are typically chronic scaly plates on the face, scalp and ears. Eventually, scars occur that may be associated with dyspigmentation and alopecia.

Histology discoid lupus erythematosus

In DLE, the sections reveal the dermis contains a perivascular and periadnexal lymphohistiocytic infiltrate under an interface dermatitis (Figure 1). the epidermal the interface activity shows the degeneracy of the basal cap, apoptotic keratinocytes and a marked thickening of the basement membrane (Figures 2, 3). In well-established lesions, there may be marks follicular tamponade (Figure 4) and, sometimes, an epidermal reaction that can mimic a scaly cell carcinoma (warty lupus erythematosus). There is a characteristic lymphohistiocytic infiltrate surrounding appendices and glasses (figure 5). Statement of dermal mucin it can be impressive (figure 6).

Special studies of discoid lupus erythematosus

The thickening of the basement membrane can be highlighted with periodic acid Schiff (PAS). Mucin may be highlighted by an alcian blue or colloidal iron stain.

Immunofluorescence can be positive for immunoglobulin (IgM, IgG and IgA) and complement at the dermoepidermal junction and around hair follicles. Band-shaped deposition at the dermoepidermal junction in non-lesional and non-solar exposed skin it is associated with (but not a diagnosis of) systemic disease.

Differential diagnosis discoid lupus erythematosus

Lichen Planus: There are some overlapping characteristics including interface activity and Civatte body formation. However, the latter is usually more conspicuous in lichen planus. Mucous Membrane lesions are particularly difficult to distinguish. Lichen planus generally lacks the deep and perianexal dermis inflammation seen in lupus Immunofluorescence has been recommended to be helpful, but the results can be confusing. For example, an overlay syndrome It is reported where there is positivity for both IgM colloid bodies at the dermoepidermal junction (lichen planus) and for granular IgG at the basement membrane (lupus type).

Jessner lymphocytic infiltrated: tumid lupus erythematosus (essentially DLE without epidermal changes) may be indistinguishable from DLE and some authorities believe that these conditions are the same entity. Mucin deposition is more consistent with DLE or tumid lupus.

Polymorphous light eruption (PMLE): deep infiltrate and some epidermal changes can cause confusion between these conditions without good clinical correlation. PMLE often shows impressive dermal papillary edema instead of the mucin seen in DLE and the thickening of the basement membrane should not generally be seen with PMLE.

Squamous cell carcinoma hypertrophic lupus may appear scaly Cancer. The infiltration and interface changes are useful features to correctly diagnose DLE. Note that squamous cell carcinoma can arise within chronic discoid lupus erythematosus.