In a patient diagnosed with Cushing's syndrome, what unexpected feature may be present?

In cases of Cushing's syndrome, the presence of unilateral adrenal enlargement is considered an unexpected feature because, typically, patients may present with bilateral adrenal hyperplasia or an adenoma. Cushing's syndrome is primarily characterized by an overproduction of cortisol, often due to factors such as an adrenal adenoma or pituitary adenoma (Cushing's disease).

When a patient has Cushing's syndrome due to an adrenal adenoma, it may result in unilateral enlargement of the affected adrenal gland, while the other gland may be atrophied due to feedback inhibition from high cortisol levels. This distinct anatomical change can be noted on imaging studies and is not always anticipated when assessing the classic symptoms of Cushing's syndrome, such as hypertension, characteristic high cortisol levels, or symptoms like oliguria.

Hypertension and high cortisol levels are expected findings in Cushing's syndrome and can help confirm the diagnosis. Oliguria, or decreased urine output, might not be a direct consequence of the syndrome itself, making its presence more variable. Unilateral adrenal enlargement is a specific finding that differentiates some forms of the syndrome and may not be seen in all patients, hence why it stands out as unexpected.