A rare case of isolated Cushing syndrome in a 3-month-old boy.

Adrenocortical carcinoma (ACC) is a rare malignancy in children. Most of these are endocrinologically active tumors, with virilizing features being typically dominant. Its presentation with isolated Cushing syndrome is rare. We report a 3-month-old infant with Cushing syndrome without the clinical features of androgen or mineralocorticoid excess consequently diagnosed with ACC. We discuss the different presentations, diagnosis, and management of this rare tumor with a rarer presentation.