Snowman sign (pituitary macroadenoma)
Snowman sign in neuroimaging refers to the configuration of many pituitary macroadenomas. As they are soft tumors they are indented by the diaphragma sellae giving them a snowman configuration (or "figure 8" or "dumbbell" configuration). This feature helps in differentiating these tumors from meningiomas extending into the pituitary fossa.
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