Endocrine Abstracts

Background: Prolactinoma is the most frequent pituitary tumour. However, peculiar aspects may induce difficulties in their evolution and management. Malignant prolactinoma is exceptionally rare and it cannot be diagnosed on histological grounds alone. We report the case of a recurrent, possibly malignant macroprolactinoma.

Case report: 46 years old female, addressed for bitemporal hemianopia, without other clinical signs. MRI confirmed a pituitary macroadenoma (22/19/35 mm) with suprasellar evolution. Hormonal profile revealed hyperprolactinemia with secondary thyroid and gonadal insufficiency, for which Cabergoline was started, with initial good evolution. Three years later she presented pituitary apoplexy with acute intracranial hypertension, solved by partial transcranial adenomectomy. Gamma knife radiation completed the treatment, with succeeding adrenal and thyroid insufficiency. After 4 years of stationary evolution under Cabergoline and substitutive treatment, an aggressive tumour progression imposed a new surgical intervention (transsphenoidal adenomectomy). One year later, intensive vertiginous syndrome enforced reinvestigations. MRI identified two cerebral tumours (meningioma?), one of them at the cranio-spinal junction, which needed urgent excision. Pathology identified pituitary adenoma cells and a Ki-67 index of 2%. Post-operatory, the patient complained of gait dysfunction, nausea and headache. Left cranial nerves paresis X, XI, and XII was objectified. The patient underwent six cycles of Temozolomide chemotherapy, with no improvement, last MRI revealing further tumour evolution.

Conclusion: Elucidating the pathogenesis of aggressive prolactinomas remains largely unknown and continues to mesmerize the physicians. The diagnosis of pituitary carcinoma is confirmed only in the presence of metastasis. After initial good response to Cabergoline, our patient developed a rapid aggressive progression of the tumour, with little effect of surgery and radiotherapy. Temozolomide was not efficient in controlling tumour evolution. In spite of the longer survival (9 years) and the low proliferation index, we believe that new markers are needed in order to assess the aggressiveness of malignant prolactinoma.