Neurofibromatosis Type I: Consensus on Current Terminology for Neurofibromas, As a Basis for Recommendations on the Use of MEK Inhibitors.

Neurofibromatosis type 1 (NF1) is characterized by the development of neurofibromas, including cutaneous neurofibromas and plexiform neurofibromas (PNFs). Despite more than a century of clinical recognition, the terminology used to describe these tumors remains inconsistent across disciplines, particularly in pathology, radiology, and clinical practice. This lack of standardized nomenclature complicates communication, diagnostic assessment, risk stratification, and therapeutic decision-making. In this multidisciplinary consensus paper, experts from the German NF Working Group sought to harmonize current terminology for NF1-associated neurofibromas, with particular emphasis on PNF, and to relate this terminology to diagnostic procedures, clinical course, and treatment considerations. A new structured terminology of NF integrating anatomic and histological descriptions is proposed. Using a modified Delphi process, the group developed consensus statements addressing the definition and classification of neurofibromas and their relevance for imaging, pathology, surgery, biopsy, and medical treatment. A unified terminology is especially important in the era of targeted therapy, as MEK inhibitors have emerged as a promising treatment option for selected patients with NF1-associated PNF. Establishing a shared conceptual framework may improve interdisciplinary communication, support more consistent clinical decision-making, and provide a stronger basis for future recommendations on the use of MEK inhibitors in NF1.