Lupus erythematosus tumidus in Japan: a case report and a review of the literature

Abstract

We report here the case of a 48-year-old Japanese woman showing plaque-forming scattered indurative papules on her face, buttock and extremities. Histological examination revealed a large amount of interstitial mucin deposition, and negative direct immunofluorescence was observed. The provocative phototesting reproduced the skin lesion, and the patient was diagnosed with lupus erythematosus tumidus (LET). A review of ten LET cases previously reported in Japan revealed that all of these cases had clinicopathological features similar to those reported for European cases, although not all of the former fully satisfied the European criteria.

Reticular erythematous mucinosis: histopathological and immunohistochemical features of 25 patients compared with 25 cases of lupus erythematosus tumidus

“…Concerning LET, DIF was positive in 64% of patients and in all these cases IgM or IgG and/or C3 were present at the DEJ suggesting that immunoglobulins and complement have a more prominent role in mediating the tissue damage than in REM. In the literature, DIF positivity in LET varies according to the different studies: a German study indicates a positivity in about a quarter of patients, while a Japanese study found a positivity in up to 50% . In one LET patient we could find IgG deposits on the DEJ, a finding that has never been reported for REM.…”