Facial follicular mucinosis in adolescence: Diagnostic and therapeutic challenges

In a recent case report published in the Journal of Dermatology Research and Therapy, Turkish clinicians describe a rare presentation of primary follicular mucinosis (FM) in a 16-year-old girl. The case, they report, highlights the diagnostic intricacies and therapeutic uncertainties that continue to challenge dermatologists.

FM, also known as alopecia mucinosa, is an uncommon inflammatory dermatosis characterized by mucin deposition within the follicular epithelium and sebaceous glands. The disorder typically manifests as follicular papules or infiltrated plaques with prominent follicular openings and associated alopecia. While the primary, idiopathic form usually affects children and young adults with a benign and self-limited course, the secondary variant is more prevalent in older patients and is frequently associated with underlying malignancies, most notably mycosis fungoides.

The reported case involved a two-year history of a slowly enlarging, erythematous, and mildly pruritic patch on the patient’s right forehead. Dermatologic examination revealed a well-defined, alopecic, erythematous 1×2 cm plaque with prominent follicular plugs and a subtle hypopigmented halo. Laboratory investigations and imaging ruled out systemic involvement. Histopathological analysis of a skin punch biopsy demonstrated a mixed lymphocytic infiltrate surrounding the follicular epithelium, mild focal follicular spongiosis, and mucin deposition confirmed by Alcian blue staining—hallmarks diagnostic of FM.

Clinicians emphasize that distinguishing primary FM from its secondary, lymphoma-associated counterpart remains challenging. Clinical and histopathological criteria, while fundamental, are not definitive. The literature suggests that molecular studies, such as T-cell receptor gene rearrangement analysis, may aid in identifying malignancy-associated FM, though clear-cut criteria are lacking. Notably, some experts propose that idiopathic FM may represent an indolent variant of mycosis fungoides, underscoring the necessity for vigilant long-term follow-up.

Therapeutic strategies for primary FM are diverse and largely anecdotal. Options include topical, intralesional, or systemic corticosteroids, retinoids, dapsone, methotrexate, minocycline, hydroxychloroquine, immunomodulators, phototherapy, and superficial radiation. In this case, topical corticosteroids led to clinical improvement, and the patient remains under observation.

This case reinforces the importance of a multidisciplinary approach, ongoing surveillance, and individualized management in adolescent patients presenting with facial FM, given the potential for malignant transformation and the absence of standardized treatment protocols.