Eccrine Syringofibroadenomatosis Revealing Schöpf–Schulz–Passarge Syndrome in a Patient with Treatment-Refractory Palmoplantar Keratoderma

Eccrine syringofibroadenoma (ESFA) is a rare adnexal proliferation of acrosyringeal origin. Multiple, diffuse palmoplantar ESFA (eccrine syringofibroadenomatosis) is a recognized cutaneous marker of Schöpf–Schulz–Passarge syndrome (SSPS), a WNT10A-related ectodermal dysplasia, although ESFA-like changes may also arise reactively in chronic inflammatory dermatoses. We report a 66-year-old woman with a 10-year history of palmoplantar lesions clinically diagnosed as psoriasis and refractory to topical therapy, acitretin, adalimumab and ixekizumab. She also had long-standing diffuse alopecia and recurrent eyelid margin lesions previously treated with electrocoagulation. Examination showed erythematous, desquamative and fissured palmoplantar plaques, diffuse non-scarring alopecia and multiple cysts along both eyelid margins. Because of treatment failure and this atypical constellation, a palmoplantar biopsy was performed, revealing a reticulated eccrine syringofibroadenomatous (ESFA-like) proliferation with dilated eccrine ducts. This histological clue, interpreted together with keratoderma, hypotrichosis and eyelid margin cysts (the core features of SSPS), prompted targeted genetic testing, which identified a homozygous pathogenic WNT10A variant, c.321C>A p.(Cys107*), confirming SSPS. Apremilast 30 mg twice daily was followed by improvement in erythema, scaling and fissuring maintained after 24 months of follow-up. This case shows how recognition of ESFA-like changes in a biopsy from presumed refractory palmoplantar psoriasis, together with subtle ectodermal signs, can uncover SSPS in adulthood.