Endocrine Abstracts

Introduction: Prolactin-secreting tumors or prolactinomas comprise the most common pituitary tumor type, acconting of 47-66% of all pituitary tumors. These tumors can be treated with dopaminergic drugs (DA) however 10-15% of prolactinomas are DA resistant.

Case 1: A 39 years old man followed for a geant agressif prolactinoma discovered following a progressive decline in visual acuity and associated with visual impairment (diplopia), the MRI of the sellar region (magnetic resonance imaging) (Figure1) had shown a voluminous endosellar process. Hormonal work-up revealed a serum prolactin level of 174,8 ng/ml and pituitary deficiencies. The ophthalmic examination found bitemporal hemianopia. The patient was then started on dopamine agonist (cabergoline 02mg/week). Two months later, the patient consults at the emergency unit for vomiting, headaches and reduced visual acuity, suggestive of apoplexy. The MRI reveals a clear increase in the sellar process at the expense of the sellar portion wich fills the entire optochiamatic citern, lifting and compressing the optic chiasm and reaching the Monro holes with the onset of dilatations of the lateral ventricles, the patient had a transphenoidal partial adenomectomy. The histological analysis confrmed a PRL tumor classified grade IIb Trouillas 2013 and the Ki67 was 12%. The MRI related two months later showed a slight tumor reduction (24x43x29mm) so the dopamine agonist was continued at the dose of 3,5mg/week. Three months later; the MRI demonstrated an increase in volume, the decision for chemo-radiotherapy such as the STUPP protocol (radiotherapy associated to 75mg/m2 of Tomozolomide). Suddenly our patient died one moth later during the Covid 19 pandemia.

Case 2: A 37 years old women followed for a resistant prolactinoma discovered following a galactorrhea and spaniomenorrhea. Hormonal work-up revealed a serum prolactin level of 292,9 ng/ml without pituitary deficiencies and the MRI of the sellar region had shown a macroadenoma. The patient was then started on dopamine agonist (cabergoline 0,5mg/week with gradual increase in doses up to 3,5mg/week. The hormonal control was never obtained and the MRI shown a 50% increase. The patient had a transphenoidal adenomectomy.

Conclusion: Prolactinomas are the most prevalent functioning pituitary adenomas and the easiest to treat by endocrinologists, being in the majority of cases responsive to medical treatment with DAs. However, up to 15% of cases are resistant, locally invasive and depict an aggressive growth pattern.