SAT-465 Somatostatin Receptor Ligand as Initial Therapy in a Patient with Pituitary Microadenoma and Acromegaly: Temporary Remission and Recurrence

Abstract

BACKGROUND: Transsphenoidal surgery is recommended as initial therapy for microadenomas causing acromegaly. Primary medical therapy with somatostatin analogues has shown to cause a reduction in the size of microadenomas and secretion of growth hormone. Normalization of IGF-1 levels with somatostatin receptor ligand does not occur in most patients treated with primary therapy. We present a case of acromegaly with microadenoma treated with somatostatin analogue showing complete resolution on MRI within 1 year of treatment. We show that after one year of treatment discontinuation, reappearance of microadenoma to original presentation and elevation of IGF-1 was noted. CLINICAL CASE: A 43-year woman presented with headaches, frontal bossing, jaw enlargement and galactorrhea. Initial tests revealed high prolactin 31.6 ng/ml (1.2- 29.9 ng/ml), elevated IGF-1 level of 233 ng/ml (68 – 225 ng/mL) and abnormal growth hormone suppression testing. Brain MRI showed a 4 mm microadenoma within the left side of the pituitary gland. She was referred for neurosurgery, which she declined. Subsequently, medical therapy was started with Cabergoline, resulting in normalization of prolactin14.2 ng/ml (1.2- 29.9 ng/ml). Somatostatin receptor ligand was initiated with lanreotide 90 mg monthly. After 1 year of treatment patient showed clinical improvement, normalized IGF-1 level 67ng/ml (68 – 225 ng/mL) and markedly reduced size of the microadenoma on brain MRI. Patient stopped the medication due to financial difficulties and within one year had a recurrence of symptoms including high IGF-1 of 331ng/ml (68 – 225 ng/mL) and reappearance of the microadenoma on brain MRI. CONCLUSION: Acromegaly is a rare and challenging disease to treat. Somatostatin receptor ligands are not recommended as primary therapy for microadenoma causing acromegaly, despite often needed as adjuvant treatment post-surgery. Medical therapy has been described for patients who do not undergo surgery but is generally not curative. Although we present great improvement in our patient with somatostatin treatment as primary therapy, remission was short lived, and patient will need surgical resection to achieve cure from her disease. Radiological recurrence after discontinuation of medical therapy has not been reported. Using somatostatin receptor ligands as initial therapy for cure of acromegaly offers benefit as demonstrated in our case, but long term remission needs to be evaluated over a longer treatment period. References Ramírez, C., Vargas, G., González, B., Grossman, A., Rábago, J., Sosa, E., Mercado, M. (2012, 1). Discontinuation of octreotide LAR after long term, successful treatment of patients with acromegaly: is it worth trying? European journal of endocrinology, 166(1), 21-26. doi:10.1530/EJE-11-0738