Heterogeneity of Growth Hormone Receptor Expression in Craniopharyngioma – Implications for Surgical Strategy

Abstract Background Recent molecular investigations for craniopharyngiomas have investigated possible predictive biological markers. Growth hormone receptor (GHR) is thought to be involved in tumor aggressiveness, and high expression of GHR is associated with shorter duration of postoperative stable disease. Case Description A 27-year-old man with a large suprasellar tumor underwent an inexplicable clinical course, illustrating the remaining diagnostic problems and implications for surgical strategy. Transsphenoidal surgery achieved gross total removal of the tumor. Histological diagnosis was adamantinomatous craniopharyngioma and immunohistochemistry revealed very low GHR expression. He was discharged with multiple hormonal supplements except for growth hormone (GH). Eighteen months later recurrence was detected, and second tumor removal was performed with coagulation of the superior surface of the remaining pituitary gland. GH supplementation was started in the following period and he could return to employment. However, further recurrence was detected. Head magnetic resonance imaging showed almost the same pattern of tumor recurrence as preoperative imaging of the second surgery, and simultaneous removal of the tumor and the normal pituitary gland was performed. Re-evaluation of histology revealed no morphological differences between the first and the third surgical specimens, but immunohistochemical staining for GHR showed diffuse and high expression in the third specimen. The difference was thought to reflect the heterogeneity of GHR, and appearance of histological hot spots could greatly affect the postoperative prognosis. Conclusion Extensive removal of the possible tumor bed may be necessary for patients requiring GH supplementation even after gross total removal of craniopharyngioma.