From Knee Pain Consultation to Pituitary Surgery: The Challenge of Cushing Disease Diagnosis.

Cushing syndrome (CS) is a rare endocrinological disorder resulting from chronic exposure to excessive cortisol. The term is used specifically when this is caused by excessive secretion of adrenocorticotropic hormone (ACTH) by a pituitary tumor, usually an adenoma. This disease is associated with a poor prognosis, and if left untreated, it has an estimated 5-year survival rate of 50%. We present the case of a 66-year-old female patient who received a referral to endocrinology for an evaluation of obesity due to right knee arthropathy. Taking into consideration her age, she was screened for osteoporosis, with results that showed diminished bone density. Considering this, combined with other clinical features of the patient, suspicion turned toward hypercortisolism. Laboratory findings suggested that the CS was ACTH-dependent and originated in the pituitary gland. After a second look at the magnetic resonance imaging results, a 4-mm lesion was identified on the pituitary gland, prompting a transsphenoidal resection of the pituitary adenoma.