Poster Presentation ESA-SRB 2023 in conjunction with ENSA

Objective

To report a case of acromegaly presenting with acute unilateral Oculomotor Nerve (CNIII) palsy.

Methods

We describe the clinical and investigation findings of a functional pituitary tumour causing CNIII palsy, highlighting the consequences of delayed presentation.

Results

A 22-year-old Korean tourist presented with acute onset headache, four days’ left sided ptosis, reduced extra-ocular eye movements and deteriorating visual acuity. This was in the context of six months of oligomenorrhoea, acne, enlarging hands and progressive diastema. There was no weight gain or galactorrhoea. Notably she had a family history of a brain tumour of unknown aetiology in her brother during childhood, in South Korea, requiring resection.

Examination revealed left sided ptosis with an associated depressed and abducted eye and dilated, unreactive pupil. Visual acuity and colour vision were impaired bilaterally. She had bitemporal hemianopia, large hands and feet and mildly splayed teeth.

Pathology demonstrated elevated IGF-1 51.66 nmol/L (range 13.65-43.81) and Growth Hormone (GsH) 5.12 mcg/L (range 0.13-9.90). The remainder of the pituitary panel was unremarkable.

MRI revealed a 44×22×39mm sellar lesion, with cavernous sinus and suprasellar extension resulting in mass effect on the optic chiasm.

She underwent urgent endoscopic transsphenoidal resection. Histology showed focally infarcted pituitary neuroendocrine tumour with strong GH immunoreaction, confirming acromegaly. Prolactin, ACTH, LH, TSH and FSH staining were negative.

She developed polyuria post-operatively, passing up to 550mL/hr.  Given the difficulty differentiating Arginine Vasopressin deficiency from GH associated free water clearance, she received desmopressin.

Post-operative visual acuity improved (Left 6/12 and Right 6/7.5). There was no improvement in extraocular movements and ptosis at day five, but modest improvement at three-week review.

Conclusions

This case highlights that large pituitary tumours can cause cranial nerve involvement and that prompt presentation with and management of CNIII palsy is essential to prevent long term neuropraxia.