What is the significance of a buffalo hump on the neck and how is it diagnosed and treated, potentially indicating Cushing's (Cushing's syndrome) syndrome?

From the Guidelines

A buffalo hump is a significant physical sign that may indicate Cushing's syndrome, a condition caused by excessive cortisol in the body, and its presence warrants a comprehensive diagnostic evaluation to confirm excess cortisol and identify the underlying cause. This fatty deposit at the base of the neck occurs due to cortisol's effect on fat redistribution, causing adipose tissue to accumulate in specific areas. The diagnosis of Cushing's syndrome involves a combination of physical examination, laboratory tests, and imaging studies, as outlined in recent guidelines 1.

Diagnostic Approach

The diagnostic approach includes:

• 24-hour urinary free cortisol measurement to confirm hypercortisolism
• Late-night salivary cortisol test to assess cortisol levels
• Dexamethasone suppression test to evaluate the body's response to glucocorticoids
• Imaging studies such as CT or MRI of the pituitary or adrenal glands to identify potential tumors
• Measurement of plasma adrenocorticotropic hormone (ACTH) levels to differentiate between ACTH-dependent and ACTH-independent Cushing's syndrome, with a cut-off value of 29 ng/l (6.4 pmol/l) having a 70% sensitivity and 100% specificity for diagnosing Cushing disease 1

Treatment Options

Treatment depends on the underlying cause of Cushing's syndrome:

• Surgical removal of tumors (pituitary adenomas, adrenal tumors) is the primary treatment for ACTH-dependent Cushing's syndrome, with a strong recommendation for unilateral adrenalectomy in patients with unilateral cortisol-secreting adrenal masses and clinically apparent Cushing’s syndrome 1
• Medication adjustment if steroid-induced
• Medications like ketoconazole, mitotane, or mifepristone to reduce cortisol production if surgery isn't possible, with ketoconazole being the most commonly used due to its easy availability and relatively tolerable toxicity profile 1
• Bilateral adrenalectomy may be recommended in certain cases, such as ectopic Cushing's syndrome or adrenal carcinoma

Management of Cushing's Syndrome

The management of Cushing's syndrome requires a multidisciplinary approach, including:

• Medical therapies to control cortisol levels, such as metyrapone or ketoconazole, which can be effective in reducing cortisol burden but have limited long-term use due to adverse effects 1
• Surgical interventions to remove tumors or affected adrenal glands
• Close monitoring of patients for potential complications, such as hypertension, hyperglycemia, and hypokalemia

Importance of Proper Diagnosis

It's essential to note that buffalo humps can also occur in conditions unrelated to Cushing's syndrome, such as obesity, HIV lipodystrophy, or long-term steroid use, making proper diagnostic evaluation crucial for appropriate management. A comprehensive diagnostic approach, as outlined in recent guidelines 1, is necessary to confirm the presence of Cushing's syndrome and identify the underlying cause, allowing for targeted treatment and improved patient outcomes.

From the Research

Significance of a Buffalo Hump on the Neck

• A buffalo hump on the neck is a characteristic feature of Cushing's syndrome, which is defined as a prolonged increase in plasma cortisol levels that is not due to a physiological etiology 2.
• The buffalo hump is described as a dramatic accumulation of fat in the dorsocervical region of the body, and it is one of the striking features of Cushing's syndrome 3.

Diagnosis of Cushing's Syndrome

• Evaluation of patients with possible Cushing's syndrome begins with ruling out exogenous steroid use 2.
• Screening for elevated cortisol is performed with a 24-hour urinary free cortisol test or late-night salivary cortisol test or by evaluating whether cortisol is suppressed the morning after an evening dexamethasone dose 2.
• Plasma corticotropin levels can help distinguish between adrenal causes of hypercortisolism (suppressed corticotropin) and corticotropin-dependent forms of hypercortisolism (midnormal to elevated corticotropin levels) 2.

Treatment of Cushing's Syndrome

• Management of Cushing's syndrome begins with surgery to remove the source of excess endogenous cortisol production followed by medication that includes adrenal steroidogenesis inhibitors, pituitary-targeted drugs, or glucocorticoid receptor blockers 2.
• Adrenal steroidogenesis inhibitors, such as ketoconazole, are commonly used to treat Cushing's syndrome, and they have been shown to be effective in normalizing urinary cortisol levels and improving clinical symptoms 4, 5.
• Other treatment options for Cushing's syndrome include radiation therapy and bilateral adrenalectomy, which may be appropriate for patients who are not responsive to surgery and medication 2, 6.