Abstract

Large cell transformation (LCT) is rarely reported coincident with folliculotropic mycosis fungoides (FMF) and is thought to be an aggressive variant of CTCL. Diagnosing FMF is difficult – often delayed 2-4 years after onset, with up to 25% of cases initially mimicking other dermatologic conditions. Herein, we present a patient initially managed for three years with dissecting cellulitis, supported by three biopsies. Despite standard treatments, her condition progressed from an indurated alopecic patch to a painful, large ulcerated plaque on the frontal scalp, accompanied by cervical lymphadenopathy and scattered patches and plaques on the head, neck, and torso. Five months after the most recent biopsy, excision of the scalp lesion and subsequent T-cell gene rearrangement confirmed FMF with LCT with clonal CD30+ CD4 T-cells with cervical lymph node involvement (Stage IVA2). Schematics of potential premalignant or intermediate inflammatory states within the realm of cutaneous lymphomas have been described. Typically, these include large plaque parapsoriasis, lymphomatoid papulosis, and pityriasis lichenoides, each with evidence of transformation into MF over time. Other entities, including atypical pigmented purpura, atypical lymphocytic lobular panniculitis, and monoclonal T-cell dyscrasia of undetermined significance, all share a spectrum of features of their malignant counterparts, but have not been shown to progress within the same patient over time. Only one other case has described an association between FMF with LCT and dissecting cellulitis; however, it lacked biopsies supporting an alternative initial diagnosis. To our knowledge, this case is the first to propose a potential premalignant process preceding FMF with LCT.