A 50-year-old woman presents with a 5-year history of headaches, generalized tonic-clonic seizures, and bilateral leg weakness. Skull films reveal hyperostosis of the calvarium. Biopsy of the responsible lesion shows a whorling pattern of the cells. Which of the following is the most likely diagnosis?
The most likely diagnosis is an intracranial meningioma. Meningiomas are slow-growing, benign tumors comprising 15% of intracranial tumors; they are most common in the elderly. They originate from either dura mater or arachnoid and are sharply demarcated from brain tissue. Meningiomas often incite an osteoblastic reaction in the overlying cranial bones. Microscopically, the meningioma cells have a tendency to encircle one another, forming whorls and psammoma bodies. Clinically, they present as mass lesions; seizures may occur. The superior parasagittal surface of the frontal lobes is a orite site of origin. This can often produce leg weakness, since the leg motor fibers that pass down through the internal capsule originate in parasagittal coical regions. Treatment of meningiomas is usually surgical. Arachnoid cysts are formed by splitting of the arachnoid membrane; most arachnoid cysts arise near the Syln fissure. They may present with mass effect, but would be unlikely to produce seizures, prominent focal signs, or reactive hyperostosis. Glioblastoma multiforme is an aggressive malignant astrocytoma that would likely have killed the patient long before 5 years had elapsed. Metastatic breast cancer would generally look different microscopically (the whorling cell pattern is characteristic of meningioma). It would be unlikely for metastatic cancer to cause a reaction in the overlying bone, or to be present long enough to cause symptoms for 5 years. Ref: Johnson J., Lalwani A.K. (2012). Chapter 62. Nonacoustic Lesions of the Cerebellopontine Angle. In A.K. Lalwani (Ed), CURRENT Diagnosis & Treatment in Otolaryngology--Head & Neck Surgery, 3e.
Arachnoid cyst
Glioblastoma multiforme
Meningioma
Metastatic breast cancer