Endoscopic Endonasal Surgery for Erdheim–Chester’s Disease of the Clivus: A Case Report

Background Erdheim–Chester’s disease (ECD) is a rare form of non-Langerhans cell histiocytosis of unknown etiology that is characterized by xanthomatous infiltration of the affected tissues by foamy lipid-laden histiocytes. The immunohistologic and microscopic characteristics of the histiocytes differentiate ECD from Langerhans’ cell histiocytosis. Although neurological manifestations are reported in up to one-third of cases, involvement of the skull base bones is very rare. To the best of our knowledge, this is the first case of ECD presenting as a focal osteolytic lesion of the clivus resected via endoscopic endonasal approach (EEA).

Case Description A 59-year-old man presented with a diagnosed diabetes insipidus of 18 months duration. MRI of the pituitary gland at the time of diagnosis did not show a pathology that could explain extent of pituitary damage. Laboratory investigations revealed panhypopituitarism. Upon presentation, repeat MRI of the brain was obtained which demonstrated a lesion in the clivus which measured 2 × 1.8 cm. The clival lesion was hypointense in T1WI and showed intense contrast enhancement. There was another well-circumscribed dural-based meningioma-like enhancing lesion (11 mm) protruding off the inferior surface of the tentorium into the cerebellum on the left side. A head CT scan demonstrated an osteolytic clival lesion. Systemic work-up did not reveal any evidence of a primary cancer or metastatic disease. The patient underwent a surgical resection of the lesion via transclival EEA. The goal of surgery was to obtain a tissue biopsy; however, a near total resection of the lesion was achieved. The surgery was well tolerated with no intra- or postoperative complications. Histopathological examination was consistent with Erdheim–Chester’s disease with evidence of BRAF mutation; therefore, treatment with vemurafenib (BRAF enzyme inhibitor) was started. At 1-year follow-up, the patient was doing well, with no evidence of disease.

Conclusion ECD should be included in the differential diagnosis when manifestations of hypothalamic–pituitary axis dysfunction, namely diabetes insipidus and panhypopituitarism, are not explained by the radiographic findings; especially when associated with well-circumscribed meningioma-like dural-based lesions. Once ECD is diagnosed, a thorough systemic work-up should be performed to determine the extent of the disease. EEA proved to be effective for management of lesions of ECD affecting the ventral skull base, in terms of cytoreduction and obtaining tissue biopsy for histopathological diagnosis.