Which of the following tumors is least likely to cause epileptiform activity in an EEG?

Pituitary adenomas are typically located in the sella turcica and may lead to hormonal imbalances rather than directly affecting the cortical areas of the brain where epileptiform activity is generated. While any brain tumor has the potential to cause seizures depending on its location and size, pituitary adenomas are less likely to invade or irritate the surrounding cerebral tissue compared to the other tumor types listed.

Metastatic carcinomas, glioblastoma multiforme, and astrocytomas typically impact brain tissue more directly due to their infiltrative nature or location, which can lead to cortical irritation and a higher likelihood of seizure activity. These tumors often disrupt normal brain function and have a propensity to cause changes in EEG readings that are indicative of seizures, making them more closely associated with epileptiform activity. In contrast, a pituitary adenoma's effects are often confined to endocrine system changes and might not lead to direct disruptions in the electrical activity of the cortex.