Rare clival localization of an eosinophilic granuloma: illustrative case.

Background: Eosinophilic granuloma (EG) belongs to the family of Langerhans cell histiocytosis (LCH) and is considered to be a benign disease typically found in children younger than 15 years of age. Here, the authors describe an EG of unusual localization and clinical presentation.
Observations: The authors report a 9-year-old girl with an EG presenting as an osteolytic lesion of the clivus. After transsphenoidal resection and histological confirmation, adjuvant chemotherapy was initiated. Presenting signs and symptoms were weight loss, episodic grimacing, and moderate ballism-like movements. After a follow-up-period of 32 months, the patient presented with a total resolution of initial symptoms and no further tumor growth.
Lessons: Although these lesions are rare, one should consider EG as a differential diagnosis when confronted with osteolytic lesions of the clivus.