Folliculotropic mycosis fungoides: An aggressive variant of cutaneous T-cell lymphoma

Objectives: To study the clinical features, therapeutic responses, and outcomes in patients with folliculotropic mycosis fungoides (FMF) and to compare our single-center experience of 43 patients with the findings from the Dutch Cutaneous Lymphoma Group. Setting: A single-center experience from the Northwestern University Multidisciplinary Cutaneous Lymphoma Group. Patients: Forty-three patients with FMF were included in the study and compared with 43 age- and stage-matched patients with classic epidermotropic mycosis fungoides (MF) with similar follow-up time. Results: Folliculotropic mycosis fungoides showed distinct clinical features, with 37 patients having facial involvement (86%) and only 6 having lesions limited to the torso (14%). The morphologic spectrum of lesions is broad and includes erythematous papules and plaques with follicular prominence with or without alopecia; comedonal, acneiform, and cystic lesions; alopecic patches with or without scarring; and nodular and prurigolike lesions. Sixty-five percent of patients had alopecia, which in 71% of cases involved the face. Severe pruritus was seen in 68% of patients. In general, patients responded poorly to skin-directed therapy and in almost all cases required systemic agents to induce even a partial remission, including patients with early-stage disease. Overall survival was poor. Patients with early-stage disease (≤IIA) had a 10-year survival of 82%, which took a steep drop off to 41% by 15 years. Patients with late-stage disease (≥IIB) had an outcome similar to those patients in the control group with conventional epidermotropic MF of a similar stage. Conclusions: The morphologic spectrum of clinical presentation for FMF is broad and distinct from those in conventional MF. This is at least partially attributed to the ability of FMF to simulate a variety of inflammatory conditions afflicting the follicular unit. The disease course is aggressive, and many patients, including those with early disease, show a poor outcome particularly between 10 and 15 years after the initial onset of disease. Response to skin-directed therapy is poor even in early-stage disease, and our best results were seen with psoralen plus UV-A (PUVA) therapy with oral bexarotene or PUVA with interferon alfa. These findings corroborate those of the Dutch Cutaneous Lymphoma Group and further validate the classification of FMF as a distinct entity.