Ten-year follow-up of a giant prolactinoma

Giant prolactinomas are rare pituitary tumours of which management can be a challenge. A 28-year-old man presented with headaches, visual impairment and behavioural changes. Clinically, the patient was found to have hypogonadism and bitemporal hemianopsia. A MRI demonstrated a pituitary tumour 76 mm in diameter and blood tests revealed a serum prolactin of 158,700 µU/mL (reference range 58-254). Initially, a craniotomy was performed. Immunohistochemistry of the tumour identified a prolactinoma with a high proliferative index and the patient was started on treatment with a dopamine agonist. A year later, neurological symptoms worsened due to regrowth of the lesion's cystic component, and so further surgery was performed. After 10 years of treatment with dopamine agonists, the prolactin levels decreased by 96.8%, there was an effective reduction in tumour size, and the neurological signs and symptoms resolved.