When A Meningioma Isn't: Endoscopic Endonasal Orbital Decompression and Biopsy of Skull Base Rosai-Dorfman Disease Treated Previously with Empiric Radiation Therapy.

BACKGROUND: Rosai-Dorfman disease (RDD) is a rare, benign histiocytosis disorder with only approximately 100 reported central nervous system cases in the literature. Even less common is skull base involvement of RDD, with about 41 reported cases. Radiographically, RDD can appear similar to a meningioma; the true diagnosis is only found with histologic analysis. Although "benign," RDD can lead to significant neurologic morbidity from the disease or unnecessary surgical and nonsurgical treatment. While rare, intracranial RDD has been treated with chemotherapy or radiotherapy, with surgery playing a limited role to relieve mass effect. Surgical approaches to the skull base are invasive and pose risk, especially for a benign and self-limiting disease like RDD. CASE DESCRIPTION: Here we present the case of a 63-year-old woman with a presumed spheno-orbital meningioma for which the patient previously underwent radiation therapy. On presentation to our facility, the patient noted pressure headaches and blurry vision, and imaging demonstrated progression of her disease. For these reasons, surgical debulking and biopsy were undertaken. CONCLUSIONS: This report demonstrates the role of EEA for tissue biopsy and decompression of the affected cranial nerves and orbit. This paradigm seems to provide a safe and effective way to manage patients with compressive symptoms, while also allowing for tissue sampling.