A unique case of olfactory nerve ganglioglioma in neurofibromatosis type 1

Neurofibromatosis type 1 (NF1), also known as von Recklinghausen disease, is an autosomal dominant neurocutaneous disorder caused by pathogenic variants in the NF1 gene. This gene encodes neurofibromin, a tumor suppressor involved in negative regulation of the RAS/mTOR signaling pathway. While cutaneous neurofibromas and gliomas are common manifestations, glioneuronal tumors are rare in NF1. We report the case of a 33-year-old man with genetically confirmed NF1, who presented with café-au-lait macules, cutaneous neurofibromas, and bilateral sensorineural hearing loss. Follow-up brain MRI revealed two contrast-enhancing lesions: one at the apex of the left petrous ridge, and another intraparenchymal mass in the left frontobasal region involving the ipsilateral olfactory nerve. The frontobasal lesion showed increased FDG uptake on PET imaging. The patient underwent microsurgical resection of this lesion. Intraoperatively, the mass was found to infiltrate the left olfactory bulb. Histopathological analysis confirmed a WHO grade I ganglioglioma, with no evidence of malignant transformation. To our knowledge, this represents the first reported case of an olfactory nerve ganglioglioma in a patient with NF1. This finding suggests a possible novel association between NF1 and neuronal tumors affecting cranial nerve I. Further studies are warranted to explore the role of NF1 in glioneuronal tumorigenesis.