RESUMEN
Adrenocortical carcinoma (ACC) is a rare malignancy in childhood. Affected children with ACC mostly present with virilization, but not the pure form of Cushing's syndrome. A 9-year-old Japanese girl was hospitalized, because of the unstable emotions and excessive weight gain. She was diagnosed as having Cushing's syndrome and a left adrenal tumor. The adrenalectomy led to the pathological diagnosis of ACC without metastasis. There was no mutation of PRKACA in the tumor-derived DNA, or p53 in peripheral blood-derived DNA. Testosterone and dehydroepiandrosterone sulfate (DHEA-S) levels were normal throughout the clinical course. On the other hand, these levels were elevated in all five reported cases of preadolescent ACC children with isolated Cushing's syndrome. The exceptional secretory behavior of ACC gave a diagnostic precaution of the rare pediatric cancer.