Solitary Eosinophilic Granuloma of the Cervical Spine in an Adult With BRAF Mutation: A Case Report and Review of the Literature

BACKGROUND: Solitary eosinophilic granuloma (EG) of the adult cervical spine is exceptionally rare, and its molecular pathological features, particularly the BRAF V600E mutation, remain underreported. This study reports such a case and reviews the relevant literature. CASE PRESENTATION: A 48-year-old man presented with progressive neck pain and acute left upper limb radiculomyelopathy. Imaging revealed an expansive osteolytic lesion at C5 with epidural extension and spinal cord compression. Single-stage anterior cervical corpectomy and fusion was performed, followed by low-dose adjuvant radiotherapy (20 Gy/10 fractions). CASE MANAGEMENT: Histopathological and immunohistochemical (IHC) analyses (positive for CD1a, Langerin, S-100, and BRAF) confirmed solitary Langerhans cell histiocytosis (EG). Over a 5-year follow-up, the patient achieved complete clinical and radiological remission, with solid bony fusion and no tumor recurrence. CONCLUSIONS: A comprehensive review of the literature on adult cervical EG was conducted. Adult cervical EG warrants a high index of suspicion and early histopathological confirmation to avoid misdiagnosis. Anterior cervical corpectomy and fusion is highly effective for lesions with structural instability and neurological deficits. Identification of the BRAF mutation provides biological insight into aggressive local behavior and a potential target for precision therapy. Radical surgery combined with low-dose adjuvant radiotherapy yields durable long-term outcomes in high-risk adult patients. CLINICAL RELEVANCE: Molecular testing for BRAF V600E in adult cervical EG aids risk stratification and may open avenues for targeted therapy in refractory or recurrent cases.