Clinical, Histopathological, and Therapeutic Features in Lupus Erythematosus Tumidus: A Retrospective Study.

Lupus erythematosus tumidus (LET) is a rare form of cutaneous lupus erythematosus (CLE) with a controversial connection to systemic lupus erythematosus (SLE). We conducted a retrospective study with 34 LET patients in a Spanish tertiary referral center from 2007 to 2019. Most were women [52.9% (18/34)], with a median age of 53.5 years. Autoimmune or rheumatologic disorders were reported in 52.9% (18/34) of cases, and other CLE variants in 26.5% (9/34). SLE occurred in 8.82% (3/34), while 64.7% (22/34) had autoantibodies. Immunohistochemical CD123 testing tested positive in 75.9% (22/34), while direct immunofluorescence (DIF) showed positivity in 31.8% (7/22) of cases. Treatment included topical agents (100%), antimalarials (73.5%), oral corticosteroids (23.5%), and immunosuppressants (14.7%). All achieved clinical remission, but a delayed response (>3 months) was linked to SLE (p=0.002) and anti-DNA antibodies (p=0.003). LET usually associates with autoimmune disorders and autoantibodies. CD123 and DIF aid diagnosis, and systemic treatment may be needed, especially with SLE and anti-DNA antibodies.