Eosinophilic granuloma of the clivus: Case report, follow-up of two previously reported cases, and review of the literature on cranial base eosinophilic granuloma

OBJECTIVE AND IMPORTANCE: To our knowledge, this is the first reported case of the use of stereotactic radiotherapy for an eosinophilic granuloma (EC) of the clivus. We report follow-up information on two previously reported cases and suggest a management plan for this rare lesion. CLINICAL PRESENTATION: We report the case of a 4.5-year-old boy who presented with a complete abducens palsy on the right with an associated head turn. A computed tomographic scan of his head revealed a lytic lesion on that side, and magnetic resonance imaging showed the mass to be of low intensity on T1-weighted images and of high intensity on T2-weighted images with heterogeneous enhancement. INTERVENTION: A transnasal stereotactic biopsy was performed, revealing an EG. The patient was treated with stereotactic radiotherapy, and he became symptom-free with radiographic resolution of his lesion. Reviewing the literature, we found 13 series with 87 cases of EG in the petrous portion of the temporal bone. EG in the cranial base occurring outside of the temporal bone or in the temporal bone and extending intracranially is, however, quite rare, with only nine other cases reported, two of them clival. CONCLUSION: These findings suggest a classification schema in which cranial base EG lesions be grouped with either the more common extracranial petrous temporal bone lesions or the very rare intracranial lesions. Although there are few cases in the literature, treatment results indicate that clival EC, and perhaps all intracranial cranial base EGs, be treated by a biopsy alone, followed by surgery or stereotactic radiotherapy if there is an incomplete resolution of the symptoms or if there is a recurrence.