Diagnostic challenges in pediatric Cushing's disease associated with chronic renal failure: a report of three patients.

Objectives: Cushing's disease (CD) in the context of chronic kidney disease (CKD) is very rare. CKD causes physiological hypercortisolism making the diagnosis of CD extremely difficult. To report 3 females with CKD and CD and to outline the principles that may guide the diagnosis of CD in this context.

Case presentation: P1. A 12.3-year-old patient with CKD secondary to steroid-resistant nephrotic syndrome on hemodialysis (HD) and a medical history of aseptic meningitis. She was referred due to the incidental finding of pituitary macroadenoma. P2. A patient with CKD secondary to bilateral renal hypodysplasia in conservative treatment. At age 16.4 years, she had significant weight gain, purple-red stretch marks, galactorrhea, and menstrual irregularities. P3. A 15.3-year-old patient with CKD secondary to steroid resistant nephrotic syndrome in conservative treatment was referred for weight gain, secondary amenorrhea, and hypertension. In all patients, diagnosis of CD was confirmed by clinical and biochemical findings. P1 and P3 underwent transsphenoidal surgery, and in P2, transcranial surgery resection was performed. Histopathological examination revealed a corticotroph adenoma in P1 and P2, and in P3, immunohistochemistry demonstrated ACTH predominance. All patients achieved remission. P1 and P2 developed pituitary deficiencies.

Conclusions: To the best of our knowledge, these are the first three reported cases of the diagnostic association of CD and CKD in children. In all cases, CS was clinically suspected and CD was confirmed through complementary exams. Given the current lack of clear diagnostic criteria for CD in CKD patients, a thorough clinical evaluation remains essential for guiding the diagnosis.