ESPE Abstracts (2014) 82 P-D-2-2-522

Treatment Options in a 14-Year-Old Boy with an Atypic Cabergolin-Resistant Macroprolactinoma with Somatostatin Receptor 2 Expression and an Increased Proliferation Rate

Angela Huebnera, Felix Reschkea, Gabriele Hahnb, Thomas Pinzerc, Matthias Meinhardtd, Anke Pypera, Salvatore Cannavòe, Gunter Stallaf & Lorenz C. Hofbauerg

aDepartment of Paediatrics, Universitätsklinikum Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany; bDivision of Paediatric Radiology, Universitätsklinikum Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany; cDepartment of Neurosurgery, Universitätsklinikum Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany; dDepartment of Neuropathology, Institute for Pathology, Universitätsklinikum Carl Gustav Carus, Technische Univerität Dresden, Dresden, Germany; eSection of Endocrinology, Department of Medicine and Pharmacology, University of Messina, Messina, Italy; fDepartment of Internal Medicine, Endocrinology and Clinical Chemistry, Max Planck Institute for Psychiatry, Munich, Germany; gDivision of Endocrinology, Diabetes and Bone Diseases, Universitätsklinikum Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany

Background: Macroprolactinomas in children below 10 years of age are rare. Usually prolactinomas respond well to dopamine agonists so that neurosurgical resection is rarely necessary. For non-responders to dopamine agonist therapy other extended treatment options have to be considered.

Clinical case: We report a 14-year-old boy who presented at the age of 11 years with headaches for 5 years and progressive bilateral vision problems. The diagnosis of a macroprolactinoma was made on the basis of elevated prolactin levels of 6727 mU/l (NR 86–324) and on typical MRI features with a large intra- and suprasellar mass infiltrating the clivus and both sinus cavernosus and displacing the chiasm. Cabergoline treatment was started immediately with increasing doses of 0.5–7 mg/week resulting in a transient fall of prolactin levels to 2000 mU/l with no reduction of tumour mass after 10 weeks of treatment. In order to prevent bilateral blindness, partial resection of the tumour was performed.

Results: Histopathology confirmed a prolactinoma with an increased proliferation rate (Ki 67) of 5% (focally up to 10%) as well as p53 (10%), and a strong somatostatin receptor 2 expression. Metastases were not found and MEN1 and AIP gene sequencing was normal. Postoperatively, cabergoline and quinagolide treatment were ineffective. The tumour partially responded to octreotide up to 30 mg/month, however prolactin levels are rising and tumour size increased again after 13 months. Repeated transsphenoidal surgery will be performed followed by either temozolamide treatment or radiotherapy.

Conclusion: Atypic macroprolactinomas with a high proliferation index starting at an age of about 6 years as in our case are extremely rare. If dopamine agonist therapy fails and the tumour cells express somatostatin receptor 2 octreotide could be one treatment option although there is little experience for this age group. Final treatment strategies may include stereotactic radiation and temozolamide.