Brown tumor, although rare, should be listed in the differential diagnosis of expansive mass lesions in the area of the sphenoid sinus and cranial base. The management is multidisciplinary, and therapeutic options should target the underlying cause.

A 33-year-old woman presented with a 3-year history of progressive numbness in the hand, cerebellar ataxia, limb weakness, nystagmus, and dysarthria. T2-weighted MRI revealed abnormal foci of increased signal intensity mimicking demyelinating plaques in the periventricular white matter, and brain 18FDG-PET scan showed increased uptake in the pons. Biopsy from a tibial lesion showed aggregates of foamy histiocytes in the intertrabecular spaces replacing the bone marrow, characteristic of Erdheim-Chester disease. The patient was treated with craniospinal radiation. After 6 months, the clinical picture was stable and the MRI was unchanged.

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Two patients with extra-axial cavernous hemangioma who presented with headache and oculovisual disturbances were investigated with computed tomography and magnetic resonance imaging. The lesions masqueraded as basal meningioma, but this diagnosis was not supported by magnetic resonance spectroscopy in one patient. Cerebral angiography with embolization was indicated in one patient, but embolization was not justified in the other. Both patients underwent a pterional craniotomy. The lesions were extradural and highly vascular, necessitating excessive transfusion in one patient in whom gross total resection was achieved, and precluding satisfactory removal in the other. There was no mortality. Transient ophthalmoplegia, the only complication in one patient, was due to surgical manipulation of the cavernous sinus; it resolved progressively over 3 months. Extra-axial skull base cavernous hemangiomas are distinct entities with clinical and radiological characteristics that differ from those of intraparenchymal cavernous malformations. They can mimic meningiomas or pituitary tumors. In some cases, magnetic resonance spectroscopy may narrow the differential diagnoses. Surgical resection remains the treatment of choice, facilitated by preoperative embolization to reduce intraoperative bleeding and by the application of the principles of skull base surgery. Fractionated radiotherapy is an alternative in partial or difficult resections and in high-risk and elderly patients.

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