Lupus Erythematosus Tumidus: Clinical and Pathological Features in a Series of 20 Patients

Abstract

Objective: We sought to assess the clinicopathologic/immunophenotypical features in patients with lupus erythematosus tumidus (LET).

Methods: All skin biopsies diagnosed as LET in 16 years were retrieved from our pathology laboratory. Clinical charts were reviewed and immunohistochemical markers were performed. Subpopulations of cells in the infiltrates were studied, as well as the number/distribution of plasmacytoid dendritic cells (PDC), which were compared with two control groups: normal skin and discoid lupus erythematosus. Direct immunofluorescence was performed when available.

Results: We found 20 patients (11 men and 9 women; mean age 43.5 years); the mean evolution previous to diagnosis was 20.3 months. They all had erythematous, nonscarring urticarial-like plaques: 8 in the head region only, 8 in trunk/limbs only; both segments were affected in 2 patients; topography was unknown in 2. Except for 1 patient, no one developed systemic lupus erythematosus. A dense perivascular/periadnexal superficial-to-deep lymphocytic infiltrate and stromal mucin deposition were characterized histopathologically; interphase changes were absent. Immunophenotype supported an inflammatory profile. The differential count of CD123 + PDC in 10/20 cases of LET (n = 1180) was notably higher than 5 cases of discoid lupus erythematosus (n = 419) and 5 cases of normal skin (n = 38). No immune deposits were found in 2 cases.

Conclusion: LET is a rare, peculiar form of cutaneous lupus erythematosus that only exceptionally evolves to systemic lupus erythematosus . Its clinical-pathologic/immunophenotypical features are very characteristic. The amount of CD123 + PDC is a very helpful feature among the criteria for its diagnosis and seems to be relevant in its pathogenesis.