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

Recent molecular investigations for craniopharyngiomas have investigated possible predictive biologic 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.

A 27-year-old man with a large suprasellar tumor underwent an inexplicable clinical course. Transsphenoidal surgery achieved gross total removal of the tumor. Histologic diagnosis was adamantinomatous craniopharyngioma, and immunohistochemistry revealed very low GHR expression. He was discharged with multiple hormonal supplements except for growth hormone. Recurrence was detected 18 months later, and removal of the second tumor was performed with coagulation of the superior surface of the remaining pituitary gland. Growth hormone supplementation was started in the postoperative period, and he returned to work. However, a 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. Reevaluation of histology revealed no morphologic differences between the first and the third surgical specimens, but immunohistochemical staining for GHR showed diffuse high expression in the third specimen. The difference was thought to reflect the heterogeneity of GHR, and appearance of histologic hot spots greatly affected the postoperative prognosis.

Extensive removal of the possible tumor bed may be necessary for patients requiring growth hormone supplementation even after gross total removal of craniopharyngioma.