MR imaging of pituitary hyperplasia in a child with growth arrest and primary hypothyroidism

Magnetic resonance imaging of pituitary hyperplasia has been rarely describ ed in children with primary hypothyroidism. We report a case of pituitary h yperplasia in a child presented with significant growth arrest and laborato ry evidence of hypothyroidism. Magnetic resonance imaging revealed symmetri cal pituitary enlargement simulating macroadenoma. After thyroid hormone re placement therapy, the child's height increased and pituitary enlargement r egressed to normal. Awareness of MRI appearance of pituitary hyperplasia in children with laboratory evidence of hypothyroidism might avoid misdiagnos is for pituitary tumor, which may also manifest as growth disorder, obviati ng unnecessary surgery.