Clinical Features and Treatment of Pediatric Somatotropinoma: Case Study of an Aggressive Tumor due to a New AIP Mutation and Extensive Literature Review

Abstract

Context: Pediatric somatotropinoma is uncommon but usually more aggressive than in adults, creating therapeutic challenges. No treatment guidelines are available. Objectives: To describe the features of pediatric somatotropinomas and to assess therapeutic strategies based on an extensive literature review. Design: We describe a pediatric case of aggressive somatotropinoma with an AIP mutation. We identified 137 pediatric somatotropinoma cases published between 1981 and 2010, and found 41 cases with AIP mutations in the main review. Results: We found a slight male preponderance (59%). Median age was 9 years at symptom onset and 14 years at diagnosis. Macroadenomas accounted for 90% of the tumors; 2/3 of the children had hyperprolactinemia at diagnosis. The first-line treatment was pharmacotherapy in one third and surgery in 2/3 of the patients. Pegvisomant was used in 7 patients and produced significant improvement in 4. The male preponderance was higher in the subgroup with AIP mutations. Mutations leading to severe protein abnormalities were more common than reported in adults. Conclusion: Higher invasiveness and tumor volume in pediatric somatotropinomas require complex treatment combinations, which produce variable results. Pegvisomant is an effective drug whose usefulness in children remains to be determined. Genetic screening, particularly for AIP mutations, should be performed routinely.