Unusual clinical presentation of primary hypothyroidism in a very young infant caused by autoimmune thyroiditis: case report and update of the literature.

Acquired primary hypothyroidism in infancy can be related to autoimmune thyroiditis and can present with unusual symptoms, such as muscle pseudohypertrophy and pituitary tumor. This condition can cause permanent deficits in psychomotor development and growth despite adequate replacement with L: -thyroxine.