Long-term Stable Unilateral Mandibular Deformity Associated With Ipsilateral Skull-base Soft-tissue Lesion and Degenerated Pterygoid Muscles in Neurofibromatosis Type 1

Sep 28, 2026

Neurofibromatosis type 1 (NF1) is an autosomal dominant tumor predisposition syndrome affecting multiple developmental and metabolic processes, including bone. This case documents diagnosis and treatment of an NF1 patient with a skull-base space-occupying lesion and prominent mandibular alterations. Over 21 years, MRI showed a left-sided diffuse plexiform neurofibroma spreading through dystrophic pterygoid muscles, while skull-base tumor extent, muscular dystrophy, and mandibular dysplasia remained stable.

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Case Report

Clinical report

doi: 10.21873/cdp.10516 Long-term Stable Unilateral Mandibular Deformity Associated With Ipsilateral Skull-base Soft-tissue Lesion and Degenerated Pterygoid Muscles in Neurofibromatosis Type 1 REINHARD E. FRIEDRICH1*, FELIX K. KOHLRUSCH1*, CHRISTIAN HAGEL2 and MANFRED GIESE3 1 Department of Oral and Craniomaxillofacial Surgery, Eppendorf University Hospital, University of Hamburg, Hamburg, Germany; 2 Institute of Neuropathology, Eppendorf University Hospital, University of Hamburg, Hamburg, Germany; 3 Department of Oral and Maxillofacial Surgery, Army Hospital Hamburg, Hamburg, Germany Abstract Background/Aim: Neurofibromatosis type 1 (NF1) is a tumor predisposition syndrome characterized by neoplasms originating from nerve sheath cells. The autosomal dominant hereditary disease also affects numerous developmental and metabolic processes, for example in the bones. The aim of the study was to document the diagnosis and treatment of an NF1 patient who had developed a space-occupying lesion at the base of the skull with noticeable mandibular changes. Case Report: The patient, who presented for her initial examination as a teenager, had an asymmetrical lower face. The deformation of the lower jaw mainly affected the left ramus and was associated with a deviation of the chin region toward the affected side. MRI revealed a diffuse plexiform neurofibroma (PNF) on the left side, which spread within the dystrophic pterygoid muscles. Over a treatment interval of 21 years, the patient developed numerous PNF in various regions of the body. The extent of the skull base tumor and the degree of muscular dystrophy remained constant during this period. Similarly, the mandibular dysplasia already noted during the initial examination remained unchanged. continued The results were partially presented orally atthe Annual Joint Symposium of the Working Group for Oral and Maxillofacial Surgery and the Working Group for Oral Pathology and Oral Medicine (Arbeitsgemeinschaft für Oral-und Kieferchirurgie und Arbeitskreis für Oralpathologie und Oralmedizin), German Dental Association (Deutsche Gesellschaft für Zahn-, Mund-und Kieferheilkunde), Bad Homburg v.d.H., 24.5.2025. *These Authors contributed equally to this work. Sur053g2e5ry9,, eE-ppenmail: dorfrfrieUdnriivcher@suityke. Hdeospital, University of Hamburg, Martinist. 52, 20246 Hamburg, Germany. Tel: +49 Prof. R.E. Friedrich (ORCID: 0000-0001-7747-9636), MD, DMD, PhD, FEBOMFS, Department of Oral and Craniomaxillofacial Received September 10, 2025 | Revised September 28, 2025 | Accepted October 1, 2025 This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. ©2026 The Author(s) . Anticancer Research is published by the International Institute of Anticancer Research. Conclusion: Although mandibular dysplasias associated with PNF are rare findings in patients with NF1, they often have a characteristic pattern and may remain unchanged for decades. Knowledge of tumor-associated mandibular dysplasia in patients with NF1 is essential for the differential diagnosis of tumors in this region which can become malignant. Keywords: Neurofibromatosis type 1, mandible, magnetic resonance imaging, panoramic radiography, plexiform neurofibroma, masticatory muscles. Introduction Neurofibromatosis type 1 (NF1), an autosomal dominant hereditary tumor predisposition syndrome, is diagnosed in approximately 1:3,000 individuals. The penetrance of the disease is complete, while the phenotype varies considerably. The gene locus is on chromosome 17q11.2 . The gene product is called neurofibromin (1). Among its known functions, the protein primarily inhibits the rat sarcoma (RAS) protein. Restriction or loss of RAS inhibition increases cell proliferation and is a frequently observed step in the pathogenesis of neoplasia and complex dysplasia in

FAQs

What was the primary aim of the study described in the document?

To document the diagnosis and treatment of an NF1 patient who developed a space-occupying lesion at the base of the skull with noticeable mandibular changes.

What did imaging show in the patient over the 21-year interval?

MRI revealed a diffuse plexiform neurofibroma on the left side spreading within dystrophic pterygoid muscles, while the extent of the skull-base tumor and muscular dystrophy stayed constant.

How did the mandibular dysplasia and facial deformity change over time?

The mandibular dysplasia identified at the initial examination remained unchanged, and the dysplasias associated with PNF were described as rare but often showing a characteristic pattern that may persist for decades.

Sep 28, 2026

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