Supplementary Material for: Extensive Alopecia Mucinosa and Response to Brentuximab Vedotin: A case report.

Abstract

Introduction:
Follicular mucinosis is characterized by mucin deposition within hair follicles and sebaceous glands, sometimes causing irreversible alopecia. In adults, it is often secondary to cutaneous T-cell lymphoma, particularly the folliculotropic mycosis fungoides variant. Extensive scalp involvement is rare and may mimic inflammatory or infectious disorders, delaying diagnosis.

Case Presentation:
A 64-year-old woman presented with progressive diffuse alopecia, suppurative scalp nodules, comedones, leonine facies, and multiple erythematous plaques. Initial biopsies elsewhere suggested tuberculoid leprosy, and multidrug therapy produced no improvement. Trichoscopy showed nonspecific signs suggestive of dissecting cellulitis, but histopathology revealed mucinous follicular destruction and a perifollicular lymphocytic infiltrate with immunophenotypic features of cutaneous T-cell lymphoma. Large-cell transformation was present in 10% of the infiltrate. Staging confirmed advanced folliculotropic mycosis fungoides with secondary follicular mucinosis. Treatment with brentuximab vedotin achieved partial hair regrowth and skin improvement.

Conclusion:
This case describes an unusual presentation of folliculotropic mycosis fungoides, in which diffuse alopecia with suppurative nodules was the first manifestation of secondary follicular mucinosis. Brentuximab vedotin may have a therapeutic role in mucinous alopecia in this context.