Objective and importance: Functional ectopic pituitary adenomas are rare and can be misdiagnosed as extensions of pituitary adenomas when they are located in the vicinity of the normal gland. In this report, we present a case of an ectopic adrenocorticotropic hormone-secreting suprasellar pituitary adenoma that caused Cushing's disease. A literature review of previously reported ectopic pituitary adenomas is included to illustrate the diverse clinical manifestations of this disease entity.
Clinical presentation: An 11-year-old boy was noted to have hirsutism, a buffalo hump, and unexplained weight gain consistent with Cushing's syndrome. Laboratory investigations revealed that the boy had elevated adrenocorticotropic hormone and serum cortisol levels unsuppressed by dexamethasone. Magnetic resonance imaging scans were suggestive of a pituitary adenoma with suprasellar extension.
Intervention: The initial transsphenoidal approach failed to achieve complete surgical resection. A repeat operation in which the pterional approach was used revealed a suprasellar pituitary adenoma without association with intrasellar contents. The patient's cushingoid symptoms improved significantly 3 months after surgery.
Conclusion: Ectopic pituitary adenomas should be considered in the differential diagnosis for all patients with Cushing's syndrome. Furthermore, surgical approaches should be chosen carefully once the diagnosis of ectopic pituitary adenoma is made.