Discordant GH and IGF-1 levels in a patient with acromegaly and fibrous dysplasia: A case report

Abstract

Introduction: Follow-up management of patients with acromegaly after pituitary surgery is performed by biochemical assessment of Growth Hormone (GH) and Insulin-Like Growth Factor-1 (IGF1). There is increasing recognition of patients who show discordance results between GH and IGF1. Clinical case: We report on a 38-year-old man with facial and ear pain on the left side. A candidate for canaloplasty, he was referred to our endocrinology clinic because he had symptoms of acromegaly. The clinical suspicion of acromegaly was confirmed using biochemical tests and Magnetic Resonance Imaging (MRI). The patient’s asymmetric facial features and a Computed Tomography (CT) scan of the skull base showed fibrous dysplasia. After transsphenoidal surgery, the patient’s complaints improved. Hypopituitarism did not occur. The patient’s IGF-1 levels were within the normal range during the postoperative follow-up period. However, the GH levels at baseline and after an Oral Glucose Tolerance Test (OGTT) remained high, which indicated discordant GH and IGF1 levels. Because the patient had normal IGF-1 levels and no clinical signs and symptoms, he was followed up every 3-6 months. The GH and IGF-1 discrepancy persisted for 3 years. After 3 years, the IGF-1 levels increased, which resulted in the patient being treated with longacting octreotide. The patient is currently in remission with medical treatment. Conclusion: The interpretation of discrepancy between IGF1 level and GH after OGTT in patients with acromegaly during the follow-up requires efficient management of clinical symptoms and biochemical markers in these patients which need close patient-physician cooperation.