ESPE Abstracts

Introduction: Pituitary gigantism is caused by a somatotroph pituitary tumor that occurs before epiphyseal closure and is associated with increased morbidity due to the systemic effects of chronic hormonal excess. It is an extremely rare disease, with an estimated incidence of 8 per million person-years. Therapeutic modalities for pituitary gigantism are the same as those for acromegaly and include surgery, medication and radiation. Medical treatment plays an important role in acromegaly and gigantism. In recent years, novel therapies and novel combinations of existing drugs have been studied in preclinical and clinical trials in order to improve clinical outcomes and reduce side effects.

Objective: To describe the case of an adolescent with gigantism, who was treated with surgery, followed by somatostatin analogues.

Case: A 15-year-old boy was referred to endocrinology for postoperative evaluation. He had partial resection of an invasive pituitary macroadenoma. His family/personal history was unremarkable. Recently his height was above his genetic potential, enlarged feet/hands, poor school performance, headache, dizziness, sleepiness and visual disturbances. Workup showed high levels of IGF1 933 ng/ml (Normal:211-512) and GH 50.3 ng/ml, with hypothyroidism, secondary adrenal insufficiency and normal gonadal function. An invasive pituitary macroadenoma was seen at MRI and ophthalmological evaluation showed bilateral temporal hemianopsia. Postoperative pathology confirmed a somatotropic adenoma (+ GH and PRL), Ki67 3% and P53 3%. No AIP, MEN1 or CDKN1B gene abnormalities were found.

Post-surgery outcome: He suffered from diabetes that required insulin pump during one year, and he persisted with high levels of IGF1 and BP3. He was treated with octreotide (30mg/month) and cabergoline (1 mg/week) for 2 years, with initial improvement of IGF1 levels and visual field, but 8 months ago he had a relapse (worsening visual fields) and was started on pasireotide. Since then, he has had stable IGF1 levels (411 ng/ml), normal glucose metabolism, stable MRI without significant changes, and improved visual fields.

Conclusions: As pituitary gigantism is rare and disease control is difficult to achieve, medical treatment with somatostatin analogues is a useful resource. In this case it showed adequate safety and a moderately good response, especially in regard to his visual fields, avoiding the need for second surgery or radiotherapy for the time being.