[Pituitary hyperplasia due to primary hypothyroidism]

Pituitary hyperplasia due to primary hypothyroidism is rare and underdiagnosed.

We report an 18-year-old patient referred for a pituitary mass revealing primary hypothyroidism. Biological parameters confirmed severe primary hypothyroidism and hyperprolactinemia. Outcome was favorable with l-thyroxin supplementation resulting in TSH and prolactin levels normalization and pituitary mass resolution.

Pituitary hyperplasia due to primary hypothyroidism, although rare, should be recognized to avoid unnecessary surgery leading to irreversible complications.