Isolated intracranial Rosai-Dorfman disease mimicking meningioma.

Sinus histiocytosis with massive lymphadenopathy (SHML), also known as Rosai-Dorfman disease (RDD), is an idiopathic histiocytic proliferation affecting lymph nodes. It is typically characterized by painless cervical lymphadenopathy, fever and weight loss. Although extranodal involvement has been reported in diverse sites, intracranial presentation, particularly in the absence of nodal disease is uncommon. To the best of our knowledge, 48 patients with intracranial masses have been reported previously. A 31-year-old man was admitted to our clinic with a 4-month history of progressive headache. His medical history was unremarkable except for occasional fever. There were not any neurological deficit and weight loss. No lymphadenopathy (particularly bilateral cervical) and extranodal involvement in diverse sites were revealed by physical and radiological examinations. Routine hematological and biochemical studies were normal except for mild leukocytosis and elevated erythrocyte sedimentation rate. The patient underwent magnetic resonance imaging (MRI) testing that revealed an enhancing mass in the left temporal lobe. Preoperative diagnosis was meningioma. The patient underwent a left frontotemporal craniotomy with complete resection of the mass. Histopathology was compatible with RDD. Extranodal RDD is rarely found intracranially. Prognosis is benign especially in the absence of nodal disease. It is clinically and radiologically difficult to distinguish from meningioma, and histological examination is essential for a definitive diagnosis.