ESPE Abstracts

Background: Pituitary hyperplasia secondary to primary hypothyroidism has been reported in adult patients but is rare in paediatric patients. Despite advances in imaging technology, distinguishing between pituitary adenoma and pituitary hyperplasia remains a challenge. This differentiation is important as the primary modality of treatment in hyperplasia is thyroid hormone replacement and not neurosurgical intervention.

Case report: A 9.3 year old girl of South Asian ethnicity was confirmed to have primary autoimmune hypothyroidism (TSH 95 miu/L, TPO antibody 663 IU/mL) in community clinic (learning difficulties, morbid obesity (BMI 51.2, BMI SDS +4.5) and social concerns). Levothyroxin was commenced and referral made to endocrine clinic. The family were lost to follow-up during Covid and seen in endocrine clinic at age of 11.2 years. TSH was >150 miu/L despite parents reporting child had been on Levothyroxin. Type 2 diabetes (HbA1c 7.4%) and deranged lipid profile were identified. Cranial MRI (organised by community team) identified an enlarged pituitary gland (1.2cm (CC) and 1.0cm (AP)), moderate uniform enhancement of the pituitary gland, thickened stalk deviated to left, extension of pituitary just above the upper border of the sella turcica superiorly but did not efface the optic chiasm consistent with pituitary macroadenoma. A normal ophthalmological assessment and normal pituitary function including normal Prolactin were confirmed. Pituitary hyperplasia secondary to long standing hypothyroidism was agreed as the likely diagnosis rather than adenoma and agreed by radiology team. Prompt admission to the ward for observed therapy and involvement of Social Care was undertaken. Normal thyroid function was achieved on treatment and repeat cranial MRI after 12 months demonstrated a significant reduction in the size of pituitary gland with no discrete mass or focal lesion. Currently, patient has remained asymptomatic, euthyroid on Thyroxin replacement and on Liraglutide treatment with improving BMI (BMI 38.5, BMI SDS +3.5) and Hba1c (5.7%).

Conclusion: Screening for primary hypothyroidism should be included when pituitary enlargement and pituitary adenoma is detected as an incidental finding on imaging. Communication between the specialty teams can improve patient outcomes by avoiding unnecessary surgery when thyroid hormone