A “fat hump on the back of the neck” refers to a dorsocervical fat pad, often called a “buffalo hump.” This localized accumulation of adipose tissue can develop due to various reasons, including underlying medical conditions, certain medications, and lifestyle factors. Understanding its causes is important for those seeking information about this physical change.
Understanding the Fat Hump
A dorsocervical fat pad is an accumulation of fatty tissue. It forms on the upper back, at the base of the neck, between the shoulder blades. This fat deposition can be firm to the touch and creates a noticeable hump-like swelling. While generally harmless, its presence can sometimes indicate an underlying medical issue that warrants further investigation.
Key Medical Conditions
One recognized medical condition associated with a fat hump is Cushing’s Syndrome. This endocrine disorder arises from prolonged exposure to high levels of cortisol, a hormone produced by the adrenal glands. Excess cortisol leads to a redistribution of body fat, causing accumulation in specific areas such as the face (“moon face”), abdomen, and the dorsocervical region, forming the “buffalo hump.”
Other endocrine disorders or rare metabolic conditions can also result in unusual fat accumulations, sometimes including the neck area. One such condition is Madelung’s disease, also known as multiple symmetrical lipomatosis.
Medication-Related Causes
Certain medications can contribute to a dorsocervical fat pad as a side effect. Long-term use of corticosteroids, such as prednisone, dexamethasone, and hydrocortisone, is a common culprit. These medications mimic cortisol’s effects, leading to similar fat redistribution patterns seen in Cushing’s Syndrome. Long-term corticosteroid therapy can be associated with Cushingoid features, including a buffalo hump, in a significant percentage of individuals.
Another class of medications linked to this condition includes certain antiretroviral drugs used in HIV treatment, particularly older formulations. This side effect is part of a broader syndrome called lipodystrophy, which involves abnormal fat metabolism and distribution. In HIV-associated lipodystrophy, patients may experience a loss of subcutaneous fat in some areas, like the face and limbs, alongside an accumulation of fat in regions such as the back of the neck. These medications can alter how the body stores and uses fat, leading to localized deposits.
Lifestyle and Other Contributing Factors
General obesity and significant weight gain can contribute to a fat hump on the neck. When the body accumulates excess fat, it can deposit in various areas, including the neck region. This accumulation can occur both superficially and in deeper deposits around the cervical vertebrae and between muscles. Studies show a direct relationship between increased neck fat accumulation and higher overall adiposity.
Genetic predisposition can also play a role, as some individuals may be more likely to store fat in specific body areas, including the upper back, regardless of their overall weight. While generalized obesity often leads to more diffuse fat deposition, it can still contribute to a noticeable dorsocervical fat pad. Less common fat distribution disorders can also manifest as unusual fat accumulations, but lifestyle factors like diet and exercise play a substantial role in managing overall body fat.
Distinguishing from Similar Conditions
It is important to differentiate a true fat hump, or dorsocervical fat pad, from other conditions that might cause a similar appearance in the neck and upper back. A common point of confusion is the “Dowager’s Hump,” which is distinct from a fat accumulation. A Dowager’s Hump is primarily a spinal curvature, medically termed kyphosis, characterized by an excessive forward rounding of the upper back. This curvature is often caused by osteoporosis, a condition leading to bone thinning and potential compression fractures of the vertebrae, rather than excess fat.
The key distinction lies in their composition: a fat hump is a soft, fatty deposit, while a Dowager’s Hump involves structural changes to the spine. Other non-fat related neck lumps can also occur, which are different from a dorsocervical fat pad. These may include enlarged lymph nodes due to infection, thyroid nodules, benign tumors like lipomas, or cysts. Any new or unusual lump in the neck area should be evaluated by a healthcare provider to ensure an accurate diagnosis.