Background
Folliculotropic mycosis fungoides (FMF) is a distinct variant of mycosis fungoides, which in rare cases may present with a solitary lesion. Reported cases describe an excellent prognosis, but follow up was generally short. Herein, clinicopathologic characteristics, long‐term follow‐up data of 9 patients with solitary FMF are presented and differential diagnosis is discussed.
Methods
From a cohort of 203 patients with FMF, 9 cases with solitary FMF were selected. Clinical data and histological sections obtained at diagnosis and during follow up were reviewed.
Results
Skin lesions, in all patients located on the head, went into complete remission after treatment with radiotherapy (6 cases) or topical steroids (1 case) or regressed spontaneously (2 cases). After a median follow up of 89 months (range 51‐203 months), 5 patients were still in complete remission, 2 patients had developed multiple skin relapses, while 2 patients had progressed to extracutaneous and fatal disease. Histologically, all patients showed marked folliculotropism, associated with syringotropism (4 cases) and/or follicular mucinosis (5 cases). Large‐cell transformation was observed at presentation (2 cases) and during follow‐up (3 cases).
Conclusions
Long‐term follow‐up data indicate that patients with solitary FMF do not always have an indolent clinical course and therefore require long‐term follow up.