New insights into folliculotropic mycosis fungoides (FMF): A single-center experience

Abstract

Background: It is generally accepted that folliculotropic mycosis fungoides (FMF) is usually typified by indurated plaques and tumors mainly on the head/neck and an aggressive course. However, its clinical manifestations have long been recognized to be quite variable, and some studies indicate a better prognosis for certain presentations.

Objective: We sought to summarize our experience with the clinicopathological presentations of FMF and impact on prognosis.

Methods: Data were collected retrospectively for adults with FMF followed up prospectively at a tertiary medical center in 1995 through 2014.

Results: In all, 34 patients presented with follicle-based patch/flat plaques, keratosis pilaris-like lesions, and/or acneiform lesions, defined clinically as early stage (IA, IB), and 15 presented with follicle-based infiltrated plaques and/or tumors, defined as advanced stage (IIB). The head/neck was involved in all tumor-stage cases, whereas early-stage lesions involved mainly the trunk/limbs. The tumor stage was characterized by more pruritus, heavier perifollicular infiltrates, greater vertical depth, and more frequent presence of eosinophils. On multivariate analysis, infiltrate density was the only significant histopathological discriminator between the stages. Estimated 5-year survival was 0.94 in the early-stage group and 0.69 in the tumor-stage group.

Limitations: Lack of long-term follow-up and relatively small sample are limitations.

Conclusion: FMF presents with 2 distinct patterns of clinicopathologic features, early stage and advanced stage, each with different prognostic implications.

Keywords: cutaneous T-cell lymphoma; folliculotropic mycosis fungoides; histopathology; mycosis fungoides; prognosis.