Clinically Silent Adrenocorticotropic Hormone−Positive Crooke Cell Adenoma: Case Report and Review of Literature

Background: Pituitary adenomas are one of the most common tumors of adulthood; however, subtypes such as Crooke cell adenoma are relatively rare. Case Description: We present the case of a 55-year-old woman who presented with new-onset intermittent headache and dizziness. Clinical and laboratory investigations were not suggestive of corticotroph tumor. However, subsequent computed tomography and magnetic resonance imaging scans revealed the presence of a suprasellar pituitary adenoma displacing the optic chiasma superiorly, with hemorrhage and sellar expansion. The lesion was removed by transsphenoidal surgery and the biopsy confirmed the lesion to be a nonfunctioning pituitary macroadenoma. Further investigation revealed that the specimen demonstrated Crooke hyaline changes, with strong immunoreactivity for adrenocorticotropic hormone. However, initial workup and postoperative testing lacked evidence of Cushing disease. There was no sign of recurrence after 1-year follow-up. Conclusions: Clinically silent Crooke cell adenomas are rare occurrences, and as such we report this case with investigation of past cases.