Endocrine Abstracts

An 11-year-old boy was referred to the paediatric department due to abnormal thyroid function tests (TFTs), prompted by symptoms of fatigue, poor appetite and constipation. His medical and family history otherwise unremarkable. Upon systemic examination; there were no evidence of hypothyroidism, such as hyperpigmentation, and he was pre-pubertal. However, it was noted his growth had slowed, with his weight and height dropping from the 75th percentile at the age of three, to between the 9th and 25th percentiles.

Biochemical analysis revealed the following results:

• TSH: 1.89 mIU/l (normal range: 0.60 - 4.84)

• T4: 7.5 pmol/l (normal range: 12.5 - 21.5)

• T3: 4.2 pmol/l (normal range: 3.88 - 8.02)

Anti-TPO antibodies were negative, cortisol levels were low at 60 nmol/l (normal range: 166 - 507 nmol/l) and ACTH 14 ng/l (normal range: 7.2-63.3 7-10am (ng/l)). Given the concerns regarding a potential central cause for these abnormalities, a low-dose synacthen test was administered, revealing a suboptimal response that suggested partial central cortisol deficiency. His IGF-1 level was 8.6 nmol/l (normal range: 12.3 - 51.4), indicating hypopituitarism. He was subsequently started on hydrocortisone, followed by levothyroxine. An MRI head and pituitary revealed an Adamantinomatous Craniopharyngioma (AC), which was exerting pressure on the optic chiasm, cerebral arteries and inferior frontal lobes. AC’s are uncommon, representing 1.2-4% of all childhood intracranial tumours. The patient showed atypical features, lacking signs of increased intracranial pressure, headaches, or visual impairment. His subtle symptoms could have delayed diagnosis. Thankfully, he did not experience visual disturbance but had regular ophthalmological assessments to monitor this. Following neuroimaging, the patient was referred to Great Ormond Street Hospital (GOSH) for a trans-sphenoidal resection. Unfortunately, ten days postoperatively, he was readmitted due to vomiting. An MRI conducted at that time revealed early refilling of the residual pituitary cystic tumour, accompanied by haemorrhagic products. While craniopharyngiomas are known to recur, this typically occurs months to years after surgery. This case emphasises the crucial need to assess cortisol levels in any instance of hypothyroidism and highlights the necessity of considering a central cause when multiple endocrinopathies are present despite minimal clinical features.