Secondary Pituitary Hyperplasia Induced by Hashimoto's Thyroiditis Related Hypothyroidism: A Case Report

Abstract

Pituitary hyperplasia associated with untreated primary hypothyroidism in children is a rare condition. There are only a few reports on this condition in children, and especially when pituitary hyperplasia is accompanied with Hashimoto thyroiditis and growth arrest. Here, we describe an unusual association of pituitary hyperplasia with hypothyroidism and growth retardation, and this was all caused by Hashimoto thyroiditis. Hormonal testing showed a low thyroxine level and a high thyroid stimulating hormone level, elevated anti-thyroglobulin, low growth hormone levels and prepubertal levels of gonadotropins. A large intrasellar mass expanding beyond the sella turcica was detected on magnetic resonance imaging (MRI). Homogeneous contrast enhancement of mass highly suggested that it was a pituitary hyperplasia rather than a pituitary tumor. Therapy with L-thyroxine resulted in rapid improvement of the clinical signs, including renewed growth, normalization of the hormone levels and resolution of the pituitary hyperplasia on MRI within 90 days. In children, prolonged unrecognized primary hypothyroidism might be accompanied by growth deficiency and pubertal disharmony. Physicians must be aware of pituitary hyperplasia in these cases. (J Korean Endocr Soc 25:72~77, 2010)