Ectopic ACTH syndrome

This code represents Cushing's syndrome caused by the overproduction of adrenocorticotropic hormone (ACTH) from an ectopic (non-pituitary) source. This typically involves tumors outside the pituitary gland, such as small cell lung carcinoma, carcinoid tumors, or pancreatic neuroendocrine tumors, leading to excessive cortisol secretion.

Use this code when documentation clearly indicates Cushing's syndrome resulting from ACTH production by a non-pituitary tumor. This diagnosis is supported by laboratory findings of elevated ACTH and cortisol levels, coupled with imaging studies identifying an ectopic tumor.

• Differentiate from pituitary-dependent Cushing's disease (E24.0) and adrenal-dependent Cushing's syndrome (E24.1).
• Always sequence the underlying ectopic tumor code first, followed by this code as a manifestation.
• Ensure documentation specifies the ectopic source of ACTH to justify this specific code.