Treatment Options of an atypic Cabergolin-resistant Macroprolactinoma with Somatostatin Receptor 2 Expression in an 11-year old Boy

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: MON 167-198-Hypothalamus-Pituitary Development & Biology
Basic/Clinical
Monday, June 17, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board MON-180
Angela Huebner*1, Felix Reschke1, Gabriele Hahn1, Thomas Pinzer1, Lorenz C Hofbauer2, Katharina D Geiger1 and Gunter Karl Stalla3
1Technical University, Dresden, Germany, 2Technical Univ Med Ctr, Dresden, Germany, 3Max-Planck Institute for Psychiatry, Munich, Germany
Introduction: Macroprolactinomas in children starting below 10 years of age are rare. Usually prolactinomas respond well to dopamine agonists such as cabergoline or quinagolide so that neurosurgical resection is rarely necessary. Serum prolactin values represent a useful parameter for treatment response as they usually correlate well with tumor mass. For non-responders to dopamine agonist therapy other extended treatment options have to be considered.

Clinical Case: We report an 11-year old boy presenting with headaches since five years, progressive vision problems of both eyes, in whom the diagnosis of a macroprolactinoma was made on the basis of highly elevated prolactin levels of 6727 mU/l (NR 86-324), concordant elevated levels of prolactin monomer of 5756 mU/l (NR <279) and on typical MRI features with a large intra- and suprasellar mass infiltrating the clivus and both sinus cavernosus and resulting in an upward-displacement of the chiasm. In addition the boy presented with ACTH deficiency requiring hydrocortisone replacement therapy. Cabergoline treatment was started immediately with increasing doses of 0.5 to 7 mg/week and only lead to a transient fall of prolactin levels to 2000 mU/l in the first two weeks with no reduction of tumor mass on MRI after 10 weeks of treatment. In order to prevent bilateral blindness, partial resection of the tumor was performed. Histopathology confirmed a prolactinoma with an increased proliferation rate of 10 % as well as p53 (10%), Ki67 (>5%) and a strong somatostatin receptor 2 expression. Metastases were not found and MEN1 gene sequencing was normal. Fortunately, the vision of the right eye improved from 0.1 to 1.0. Postoperatively, cabergoline and quinagolide treatment were ineffective (polactin levels >3000 mU/l) whereas a short octreotide test resulted in a decrease of prolactin to 1136 mU/l. We therefore recently started octreotide treatment and expect positive effects in the further course.

Clinical lessons: 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, further treatment options such as neurosurgical resection need to be considered. When tumor cells express somatostatin receptor 2, octreotide is one option although there is only little experience for this age group. Pasireotide was reported to have the drop on octreotide but there is no evidence for children so far. Final treatment strategies may include stereotactic radiation and temozolamide. AIP gene mutations are considered despite the fact that the patient is the only affected family member.

Nothing to Disclose: AH, FR, GH, TP, LCH, KDG, GKS

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