Endocrine Abstracts

This case reports a 38-year-old woman with poorly controlled hypothyroidism who developed pituitary hyperplasia as a secondary complication. She initially presented with intermittent headaches, and MRI imaging revealed an enlarged pituitary gland with suprasellar extension compressing the optic chiasm. Her medical history included Hashimoto’s thyroiditis followed by a total thyroidectomy. Despite this, her thyroid function remained highly variable, with thyroid-stimulating hormone (TSH) levels often exceeding 100 mIU/l, indicating inadequate control of her hypothyroidism. Upon further evaluation, a multidisciplinary team decided to increase the patient’s levothyroxine dose and provided counselling on proper medication administration to optimize absorption and adherence. Subsequent MRI imaging, following improved thyroid function, demonstrated a reduction in the size of the pituitary swelling, correlating with lower TSH levels. Pituitary hyperplasia, a non-neoplastic enlargement of pituitary cells, can occur in patients with primary hypothyroidism due to insufficient negative feedback from thyroid hormones. This results in increased secretion of thyrotropin-releasing hormone (TRH), which stimulates pituitary growth. Unlike pituitary adenomas, which are tumours potentially requiring surgical intervention, pituitary hyperplasia due to hypothyroidism is generally reversible with optimized thyroid hormone replacement therapy. Imaging modalities such as CT and MRI reveal an enlarged pituitary gland. Differentiating between a pituitary adenoma and hyperplasia is essential and requires a multidisciplinary team discussion. Prior to contemplating surgical intervention, it is imperative to thoroughly assess both radiographic imaging findings and biochemical test results. For individuals with hypothyroidism in whom pituitary enlargement is incidentally detected during unrelated brain imaging, the recommended approach involves initiating thyroid hormone replacement therapy, closely monitoring the condition, and periodically conducting follow-up imaging studies. Patient adherence to thyroid hormone therapy is crucial as non-compliance can lead to persistent or recurrent elevated TSH levels, potentially causing the hyperplasia to return or worsen and prompting consideration of unnecessary surgical interventions if misinterpreted as a tumour.