Endocrine Abstracts

Case history: We report a 25-year-old man who presented to Neurology with two years history of a migrainous headache mainly at night. MRI head scan demonstrated large lobulated pituitary macroadenoma with significant suprasellar extension and anterior visual pathway compromise along with distortion of the basal forebrain, particularly on the right. Consequently, he was referred to the endocrinology team for further management. Upon initial assessment, he reported foot size enlargement, loss of libido and erectile dysfunction. He was found to have acral facial enlargement when compared with his previous photos and thyroid goitre. The visual assessment showed mild bitemporal hemianopia and reduced colour vision.

Result and treatment: His biochemical investigation revealed significantly raised GH 207 ug/l and IGF1 84.6 nmol/l (16.3–39.3). Borderline low LH 1.8 IU/l (1.7–8.6) and FSH 1.6 IU/l (1.5–12.4) along with very low Testosterone 2.3 nmol/l (7.6–31.4) consistent with hypogonadotropic hypogonadism with mild secondary hypothyroidism. The diagnosis of acromegaly was confirmed by the failure of GH suppression during OGTT with nadir level 215 mcg/l. He was commenced on Lanreotide 60 mg every 4 weeks preoperatively. Trans-sphenoidal resection of the macroadenoma was performed. Histology showed sparsely granulated GH adenoma with elevated Ki 67 of 8%. This adenoma subtype is classified as a special aggressive variant in the WHO classification of tumours of the pituitary gland (2017). Unfortunately, complete excision of the tumour was not possible given the substantial size at presentation. Lanreotide dose was increased to 90 mg/four weeks however, biochemical remission was not achieved with persistently high GH and IGF1. Postoperative MRI scan showed significant residual lesion with suprasellar extension and compression of the optic chiasm. His visual deficit resolved postoperatively. Subsequently, further debulking surgery was performed three months later through craniotomy and somatostatin analogue dose was increased to 120 mg/four weeks. Six months later, Growth hormone and IGF1 were still raised at 78 ug/l and 76 nmol/l respectively. Cabergoline was started at 0.5 mg/week and titrated up to 2.5 mg/week with no significant side effects. His active disease is very resistant to medical and surgical interventions. Eventually, the patient received external beam radiotherapy 50.4 Gy and has been considered for pegvisomant therapy.

Discussion: Our patient represents a very challenging acromegaly case. Despite having various medical therapies and surgical resections, his disease still very active as illustrated above. Growth hormone receptor antagonist has been considered while awaiting radiotherapy effect. Genetic testing results awaited.