POMC and mesenchymal cell neoplasm: CNC has the following characteristics: it is common in young people (10–20 yr); it typically presents with small nodular hyperplasia; patients exhibit low or undetectable blood ACTH levels; high-dose dexamethasone cannot reduce blood cortisol levels, which undergo repeated and unexplained abnormal increases; patients are positive for adrenal excitatory immunoglobulin; and onset is correlated with CNC-related genetic mutation and may be associated with mesenchymal tumors (particularly atrial myxomas), skin pigmentation and peripheral nerve damage (12).