Underrecognized clinical features of folliculotropic mycosis fungoides: a large clinical series

Summary Background and Objective A rare variant of mycosis fungoides (MF), folliculotropic MF (FMF) is characterized by a broad clinical spectrum that primarily includes follicle‐based lesions but also many atypical clinical manifestations. The objective of the present study was to conduct a clinical analysis of patients with FMF, with a particular focus on highlighting underrecognized dermatological features. Patients and Methods Overall, 27 FMF patients enrolled in our department';s MF registry, which includes 572 patients, were retrospectively reevaluated with regard to demographics, clinical features, treatment modalities, follow‐up, and outcomes. Results Besides the well‐known clinical features of FMF, we found lichen spinulosus‐like lesions in association with hypopigmentation (n = 3) and alopecia (n = 2), infiltrated/elevated erythematous facial plaques initially considered to be lupus tumidus (n = 2), pseudotumoral lesions clinically mimicking tumor‐stage MF (n = 1), persistent excoriations (n = 1) and erythematous facial papules mimicking rosacea (n = 1), as well as white dome‐shaped asymptomatic papules/nodules filled with mucin (on histology) (n = 2) that overlay other disease‐related lesions. Various therapeutic methods were used with variable results. Eight (29.6 %) patients had late‐stage disease. Conclusions Awareness of underrecognized clinical manifestations may be key to reducing delayed diagnosis of this aggressive MF variant.