ESPE Abstracts

Giant prolactinomas are rare tumours, with a prevalence of 0.5–4.4% among all pituitary tumours. In the literature, relatively few series describing their management and outcomes are available; moreover, only individual case reports of giant prolactinomas in children have been documented. We report a 10-year-old boy presented with painless progressive vision loss, insidious in onset, and bitemporal headache of six mounths duration. On physical examination; height: 134.2 cm (3-10p), weight: 34 kg (25-50p), BMI: 20kg/m2 (50-75p), prepubertal (Tanner stage 1) other system examinations were found to be normal. Magnetic resonance imaging showed supra-parasellar area, cavernous sinus, both internal carotid arteries, right temporal fossa and optic chiasm a mass with an extending cystic component was detected. The tumour had a maximum diameter of 42x40x46 mm. The laboratory investigations detected elevated prolactin levels (8730ng/ml), TSH: 2.83µıu/ml, fT4: 0.83 ng/dl, FSH: 0.41 ıu/l, LH: <0.2 ıu/l, ACTH: 17.9 pg/ml, Cortisol: 14.2 µg/dl, IGF-1: 141ng/ml(-2;-1SD), IGFBP-3: 4440ng/ml(0;-1SD). The patients were firstly partial reduction in size of the tumours and started on dopamine agonist therapy Histopathological and immunoisthochemical exams described prolactin-secreting adenoma features. Proliferation markers, Ki-67 expression:15 % (≥ 3% high) and mitotic count:8 (The number of mitoses observed is >2 per 10 high-power fields). Nowadays, after nine months from diagnosis, dopamine agonist treatment leading to reductions in tumor sizeş (12x5 mm) and prolactin levels(13 ng/ml) in the normal range. After resection and dopamin agonist therapy visual function stabilized.

Conclusion: Giant cystic prolactinomas in childhood are extremely rare. Having very high prolactin levels, diffuse invasion of the mass and High KI-67 index that is expected to have a bad prognosis. Short-term therapy with cabergoline together with a pituitary surgery in our patient was the key for the successful management, achieving biochemical and clinical remission in our patients.

Keywords: Cystic Giant Prolactinoma, Hyperprolactinemia, KI-67 Index, Dopamine Agonist Treatment, Endoscopic Transsphenoidal Surgery