Annular Lichenoid Dermatitis (of Youth): Report of a Case With Lichen Planus-Like Features.

Annular lichenoid dermatitis of youth (ALDY), a dermatosis with peculiar clinical and pathological features, represents still a debated entity, given its similarity, among others, with mycosis fungoides. A case of ALDY in a 50-year-old male patient is reported. Clinically, the patient presented an oval scleroderma-like plaque on the right flank. Histology and immunohistochemistry showed the classic appearance described in ALDY. T-cell receptor rearrangement was absent. Interestingly, a focus consistent with lichen planus was observed. The lesion resolved with topical steroids and at a follow-up of 24 months no recurrence has been registered. The case described herein supports the hypothesis that ALDY is a reactive lichenoid dermatosis, closely related to lichen planus.