Folliculotropic Mycosis Fungoides with Alopecia and Eruptive Comedones in an Adolescent Boy

Aims: Folliculotropic mycosis fungoides (FMF) is an uncommon variant of mycosis fungoides, rarely described in children. This type of lymphoma is particularly unresponsive to treatment and has a poor prognosis. Paradoxically, it can be clinically confused with conditions as benign as acne or alopecia. Hence the interest of our case report.

Case Report: A 15-year-old adolescent presented to our clinic with alopecia of the scalp associated with depilation of the axillae and pubic area. The clinical examination revealed infiltration of the scalp and axillae with fine scales and numerous open comedones, as well as non-pruritic erythematosquamous patches on the hips and thighs. Anatomopathological and immunohistochemical examination confirmed the diagnosis of FMF without mucinosis. The patient was put on topical steroids, then on methotrexate without improvement.

Discussion: FMF is a rare form of primary cutaneous T-cell lymphoma. It is a well-defined variant of mycosis fungoides characterized by infiltration of the pilosebaceous follicles with atypical lymphocytes, with or without mucinosis. This may be clinically expressed by acne-like lesions, comedones or even depilation of the hairy areas. Different differential diagnoses exist. This condition is mostly seen in elderly subjects and much more rarely in children and adolescents.

Conclusion: Its resistance to usual treatments and its poor prognosis encourage practitioners to evoke this particular entity even in the pediatric population to ensure an early diagnosis and a better management.