Endocrine Abstracts

Giant prolactinomas are rare and their treatment and outcome has been addressed only in isolated case reports. Some patients develop treatment-resistant tumors. We describe a patient with an invasive PRLoma resistant to conventional therapy. A 40-year-old female was diagnosed at age 22 a PRLoma who, although having received all available formulations of dopamine agonists over a period of 18 years, responded neither clinically, nor hormonally (PRL 9560.0 ng/ml, nv <20). At 42 years she underwent trans-sphenoidal tumor resection, but PRL levels remained elevated (1050 ng/ml) even under high cabergoline dosage (0.75 mg/die). Empirical somatostatin analog treatment (octreotide 120 mg s.c./4 weeks) was also tested with with no result. After nearly 20 years from diagnosis suddenly the tumor started growing in size with severe headache, impairment of cognitive function and PRL level increase (>10 000 ng/ml). The polyethylene glycol (PEG) precipitation test recovered elevated serum prolactin indicating that no macroprolactin was present. MRI showed the further growth of the large pituitary mass, invading the left cavernous sinus, with partial internal carotid artery occlusion and compression of the hippocampus and the third ventricle. Despite the additional trans-sphenoidal surgical procedure followed by gamma-knife radiosurgery, the patient is still with size tumor progression (diameter close to 6 cm). Because the patient has been judged unsuitable for re-intervention or gamma-knife treatment, and external radiotherapy has been without efficacy, she is now waiting for treatment with receptor-mediated radiotherapy with Yttrium-90 DOTATOC. This case emphasizes the importance of giant prolactinomas monitoring, the possibile sudden change of their behaviour with invasive and compression complications and the need to secure to all available treatments.