Spiky follicular mycosis fungoides: a clinicopathologic study of 8 cases.

Background. The early stages of follicular mycosis fungoides (FMF) have not been described previously in the literature. Objective. Our goal was to better categorize the clinicopathologic features of early stages of FMF. Methods The clinical notes of patients with a diagnosis of FMF seen during the previous 5 years were reviewed to identify any cases that at presentation had only hyperkeratotic follicular lesions. Results Eight patients (five male, three female) with a mean age of 55.4 years were enrolled. Noteworthy, FMF was not a clinical consideration in any of these patients initially. Patients presented with disseminated, slightly erythematous, hyperkeratotic, spiky follicular papules which, histopathologically, showed hyperkeratotic columns protruding from follicular plugging in concert with selective infiltration of the infundibular epithelium by atypical, mostly CD4+, lymphocytes. T-cell clonality was demonstrated in four of eight cases. The mean duration of the lesions before diagnosis was 17.1 months. The course was indolent in most of the cases (median follow up: 18 months), whilst progression to overt FMF was noted in two patients. Limitations The number of cases is small and follow up relatively short. Conclusions Spiky FMF is a deceptive clinicopathologic presentation of FMF that has been poorly described and that can mimic numerous follicular disorders.