Endocrine Abstracts

Introduction: Giant prolactinomas are rare tumours, representing 2–3% of all prolactin (PRL)-secreting tumours. Their definition is restricted to pituitary adenomas with a diameter ≥4 or ≥2 cm of suprasellar extension, very high PRL concentrations (≥1000 ng/ml) and no concomitant GH or ACTH secretion. They are more common in young to middle-aged men. Endocrine symptoms are often present for a long period of time, but most times the diagnosis is made when neurologic complications occur.

Purpose: We present a rare case of giant prolactinoma and review related literature.

Clinical case: The patient is a 40 years old male, with no personal or family history of endocrinopathy. On July 2014 he rushed to the Emergency Department at CHAlgarve due to a change in behaviour, confusion and loss of sphincter control occurring over the previous 2 days. The sellar-MR showed a mass with 68×46×50 mm, intense contrast enhancement, involving intra and left parasellar with hydrocephalus and erosion of bone pavement. The patient underwent ventriculoperitoneal drainage and was admitted in the neurosurgery department. The laboratory study showed PRL >2000 ng/ml (3.46–19.40 ng/ml) and free testosterone 3.1 pg/ml (7.20–23 pg/ml). He started cabergoline 0.5 mg/day, two pills per week. While recovering in the ward it was possible to establish a 2 years of progressive worsening headache, left lateralized, about 1-month, diplopia, right hemianopsia and symptoms of hypogonadism. One month after starting therapy he presented with rinorraquia, needing an endoscopic intervention to repair the sellar pavement. Patient re-evaluation after 6 weeks therapy revealed a 29.4% tumour diameter reduction and after 5 months a significant symptomatic improvement occurred, with normalisation of PRL and testosterone.

Conclusion: In patients with giant invasive pituitary adenoma it is important to evaluate pituitary function. Clinicians should be aware of hook effect. Although naïve or acquire resistance to dopaminergic agonists are most frequently in these tumours, medical therapy should be considered as first-line treatment in most patients.