Abstract

Folliculotropic mycosis fungoides (FMF) is a variant of mycosis fungoides typified by acneiform lesions, follicular papules, and folliculotropic neoplastic T-lymphocytic infiltrate. Initial studies demonstrated a worse prognosis than patients with classical MF. A proposed staging system incorporating clinical and histopathologic criteria in FMF determined that there are two prognostic classes for plaque stage FMF – early and advanced stages, with a worse prognosis associated with the advanced subgroup; this study attempted to validate this system.

81 patients with FMF (51 males; 30 females; median age 62 years) were categorized by clinical presentation into early (patches, papules, acneiform lesions; 19 patients), intermediate (plaques; 41 patients), and advanced (nodules, tumors, erythroderma, extracutaneous involvement; 21 patients) lesions. Skin biopsies were blindly reviewed to determine final cutaneous stage (early versus advanced), based on the density and depth of infiltrate and atypical cytology, to confirm early and advanced stage and to subdivide intermediate stage lesions. Early stage lesions had sparse, superficial to mid-dermal infiltrates; advanced stage lesions had dense, deep infiltrates and/or atypical cytology. Kaplan-Meier curves were used to compare overall survival (OS) and disease-specific survival (DSS).

39 patients were categorized as early stage and 33 were categorized as advanced. Clinical and histopathologic findings correlated well in all early and advanced cases except two, which were categorized through consensus. A statistically significant difference in disease-specific survival (p=0.016) between early versus advanced cutaneous stage (5-year DSS 100% versus 74.4%, respectively) was noted. Thus, incorporating clinical and histopathologic features provides some utility for staging in FMF.