Rosai-Dorfman Disease Presenting as a Lateral Skull Base Tumor with Intracranial Spread: A Case Report

Objective: The goal of this study is to report the clinical presentation, radiographic and pathology findings, in a patient with an intracranial tumor resembling a meningioma.

Patient: A 53-year-old man had presented to Neurosurgery three years ago with numbness in his right cheek and diplopia. His medical history was unremarkable except for hyperlipidemia. Magnetic resonance imaging (MRI) of the brain showed an enhancing CP-angle soft tissue mass with a dural tail, infiltrating the right cavernous sinus resembling a meningioma. The patient underwent a 6-week course of stereotactic radiation with complete resolution of the sensory changes in his right cheek. A three-month follow-up MRI showed stable tumor size with no signs of progression. Two years after the completion of radiotherapy, the patient presented with right-sided facial numbness and was recommended observation. Brain MRI, three-years after radiotherapy showed significant enlargement of the mass with involvement of the right cavernous sinus and extending into the right posterior fossa with mass effect on the brainstem. A trans-temporal craniotomy and trans-labyrinthine resection of the cerebellopontine angle (CP) tumor was performed. Frozen section showed chronic inflammatory tissue but permanent section showed fibrotic inflammatory lesion with numerous plasma cells and background histiocytic cells. Immunohistochemistry indicated the presence of S100 and CD58 positive histiocytic cells, a portion of which showed emperipolesis and a pathology diagnosis of Rosai-Dorfman disease of the CNS was made.

Conclusion: Rosai-Dorfman disease (RDD), also known as sinus histiocytosis with massive lymphadenopathy (SHML), is a rare benign idiopathic histiocytic proliferative disorder typically characterized by bilateral painless cervical lymphadenopathy. Although extranodal involvement has been reported, central nervous system (CNS) manifestation is rare and accounts for only 5% of cases. The case highlights the challenges of diagnosing this disease preoperatively and differentiating it from a meningioma.