2. Craniopharyngioma presenting as bilateral carpal tunnel syndrome

Publication date: April 2018
Source:Clinical Neurophysiology, Volume 129, Issue 4
Author(s): P. Joshi, I. Rosemergy
A 35 year-old Caucasian information technology professional developed bilateral hand paraesthesia, increasing in severity over two months. He reported recent onset photophobia. He was obese with a weight of 138 kg and body mass index of 47.5 kg/m². Visual acuity was 6/6 on the right and 6/18 on the left. Visual fields were normal to confrontation. There was no relative afferent pupillary defect and optic discs were normal. There was mild weakness of abductor pollicis brevis and mild sensory disturbance affecting his fingers in the median distribution bilaterally. Phalen's test was positive. The remaining neurological examination was normal. Nerve conduction studies showed bilaterally prolonged median distal motor latencies (6.5 ms on left, 6.9 ms on right), bilaterally absent sensory potentials at digit two, and prolonged median lumbrical motor latencies compared to the ulnar interosseus, consistent with severe carpal tunnel syndrome (CTS).Blood tests performed in view of the rapid onset of symptoms showed normal haemoglobin A1c and vitamin B12 levels. Thyroid function tests showed a low thyroxine of 3.4 pmol/L (normal range 10–21) and inappropriately normal thyroid stimulating hormone of 3.3 mIU/L (normal range 0.4–4.0), suggestive of secondary hypothyroidism. Further pituitary function tests confirmed panhypopituitarism. MRI brain showed a suprasellar cystic mass with an enhancing wall, suggestive of a craniopharyngioma. Visual field testing was consistent with compression of the optic chiasm. The patient was started on hydrocortisone and thyroxine and underwent transsphenoidal resection of the tumour. His hand paraesthesia and visual symptoms resolved within two weeks. Repeat nerve conduction studies after five months showed significant electrophysiological improvement.Craniopharyngiomas are cystic suprasellar tumours arising from remnants of the craniopharyngeal duct (Levy, 2004). They commonly present with headache, visual field defects, panhypopituitarism and hypothalamic dysfunction resulting in obesity and somnolence. CTS has not previously been reported in this context. There is a modest association between hypothyroidism and CTS (Shiri, 2014). A combination of hypothyroidism and obesity likely predisposed this patient to CTS. Routine screening for thyroid disease is not recommended in patients with CTS due to low yield.



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