Lupus erythematosus with exclusive involvement of the acrosyringia.

Cutaneous lesions of lupus erythematosus (LE) show a broad spectrum of clinicopathologic features. Histopathologically, besides typical patterns such as interface dermatitis, perivascular lymphocytic infiltrate and dermal mucin deposits, an involvement of the eccrine structures, especially the acrosyringium, may be observed. We describe the case of a 21-year-old woman with a 4-year history of systemic LE, who presented with a 'butterfly' rash over the cheeks as well as erythematous macules on the arms and décolleté. Biopsy from one lesion on the arm revealed interface changes, necrotic keratinocytes and exocytosis of lymphocytes restricted only to the regions of the acrosyringia. The epidermis between affected acrosyringia was normal with no hints of interface dermatitis. The eccrine glands and coils were not affected. In the dermis there were only sparse inflammatory infiltrates. Differential diagnoses such as erythema multiforme, drug eruption and lichen planus could be ruled out because of histopathologic features and clinical presentation. This is an example of a peculiar histopathological variant of cutaneous LE, characterized by exclusive involvement of the acrosyringia. The histopathologic features represent a pitfall in the diagnosis and can be correctly interpreted only upon correlation with clinical data.