Lipoma is a fatty tumor below the skin. Symptoms of lipoma include a soft mass under the epidermis, which is sometimes painful and requires treatment.

Lipomas

A. JABBAR DENTAL CLINIC KARACHI

Sadia Khan

Overview

Lipomas are defined as noncancerous, slow-growing, fatty tissue growths that develop under your skin. They are rarely harmful and typically do not require treatment. 
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Lipomas are benign, fatty lumps situated between the skin and muscle line, and not attached to the underlying muscle fascia. It is generally slow growing and harmless, with no risk for malignant transformation<a href="#accordion">[2]</a>. However, they are often confused with liposarcomas, a rare cancer of the fatty tissue.

The term &quot;universal tumour&quot; is often used for&nbsp; lipomas due to their extensive presence anywhere in the body. Its gross appearance is usually an irregular lobule-like structure enclosed by a thin, fibrous capsule. It is yellow and greasy in nature because of adipocytes, also referred to as fat cells. These masses are typically less than 2 inches wide but may be larger. 
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Lipomas are most commonly found on the head, neck, shoulders, back, or arms. Although they are commonly singular, some patients might have more than one. They can develop at any age but are most common between the ages of 40 and 60. Lipomas often&nbsp; run in families or may result from an injury. Most lipomas are painless unless pressed or injured.

Lipomas afflict approximately 1% of the population, with an annual incidence of 2.1 per 1000 people<a href="#accordion">[2]</a>. However, this incidence is probably underreported. Lipomas account for 16% of small, benign neoplasms in the gut, which is lower than leiomyomas (18%) but greater than adenomas (14%)<a href="#accordion">[1]</a>. 
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Lipomas are commonly classified based on their histology and location. Histologic variants of lipomas are listed below: 
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1.&nbsp;Angiolipoma: Fats and blood vessels are collectively present in this type of lipoma and are usually painful. 5-17% of all lipomas are angiolipomas<a href="#accordion">[9]</a>. They can be further divided into two types: 
&nbsp;

<ul>
	<li>Non-Infiltrating&nbsp;Angiolipoma which is considerably more common. It doesn&rsquo;t extend deep into the skin, however, it may be painful.</li>
	<li>Infiltrating Angiolipoma occurs less frequently. Muscles, fat, or fibrous tissue deep within the skin are affected. They are often painless. 
	&nbsp;</li>
</ul>

2.&nbsp;Conventional Lipoma: It is the most common type of lipoma and is composed of mature white fat cells. White fat cells are energy storage cells. 
&nbsp;

3.&nbsp;Fibrolipoma: This type of lipoma consists of fat and focal fibrous tissue. However, a sclerotic lipoma consists of focal fat in a predominantly fibrous lesion. 
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4. Hibernoma: While most types of lipomas contain white fat cells, hibernoma is composed of brown fat. Brown fat cells produce heat and aid in the regulation of body temperature. 
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5. Myelolipoma: It contains fat tissues which produce white blood cells, unlike conventional lipomas. 
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6. Pleomorphic Lipoma: Fat cells of various sizes and shapes are present in this type of lipoma. 
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7. Spindle Cell Lipoma: Spindle cell lipoma is an uncommon form of lipoma. As the name indicates these lipomas are composed of spindle-like fat cells which are longer than they are wide. It commonly manifests in your shoulder or the back of your neck. They only account for 1.5% of all lipoma diagnoses<a href="#accordion">[3]</a>. 
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Signs and Symptoms

Lipomas are often roundish lumps that are soft and rubbery to the touch. Gentle pressing can be used to shift the lipomas slightly beneath the skin. Lipomas are not usually painful unless they affect joints, organs, nerves or blood vessels.

A deep lipoma can put pressure on internal organs or nerves, resulting in discomfort. For instance, a person having a lipoma on or near the intestines may feel nausea, vomiting, and constipation.

These are the few common characteristics of lipomas: 
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<ul>
	<li>Encapsulated - due to encapsulation they don&rsquo;t spread to the nearby tissues.</li>
	<li>Round or oval shaped - these lumps are usually symmetrical.</li>
	<li>Moveable - they are just beneath the skin surface and move when you touch them.</li>
	<li>Size - The diameter is less than 2 inches, however, in few cases it may be larger than 6 inches.</li>
	<li>The growth of lipoma is generally slow.</li>
	<li>Painless - Lipomas are generally painless. But some can cause pain or discomfort depending on their size, location, and whether blood vessels are present nearby. 
	&nbsp;</li>
</ul>

Causes

Even though the causes of lipomas are unknown, several studies have shown a genetic connection; roughly 2-3% of people with lipomas have a family history of the benign tumor<a href="#accordion">[4]</a>. Lipoma may also develop in the region where the injury causes significant impact.

While lipomas mostly appear singularly, multiple lipomas can also form across the body. They are caused by: 
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<ul>
	<li>&nbsp;Dercum&rsquo;s Disease:&nbsp;is also known as Ander&rsquo;s syndrome or adiposis dolorosa. Multiple, uncomfortable fatty tissue growths are a hallmark of the rare condition. The growths typically appear on the trunk, arms, and legs. 
	&nbsp;</li>
	<li>&nbsp;Gardner Syndrome:&nbsp;It is a kind of familial adenomatous polyposis (FAP) condition that causes lipomas and other health issues. 
	&nbsp;</li>
	<li>&nbsp;Hereditary Multiple Lipomatosis: This condition, also known as familial multiple lipomatosis, is hereditary. 
	&nbsp;</li>
	<li>&nbsp;Madelung&rsquo;s Disease:&nbsp;Also known as multiple symmetric lipomatosis, Madelung&rsquo;s disease is characterized by lipomas on the neck and shoulders. It is particularly common in alcoholic males. 
	&nbsp;</li>
</ul>

Diagnosis

A lipoma is typically diagnosed during a physical examination. The doctor assesses the hardness of the lump, its size, whether it&#39;s painful or tender, its mobility, and changes in the overlying skin. In some cases, doctors may arrange for an imaging test such as: 
&nbsp;

<ul>
	<li>Ultrasound</li>
	<li>Magnetic resonance imaging (MRI) scan,</li>
	<li>Computed tomography (CT) scan</li>
	<li>X-Ray 
	&nbsp;</li>
</ul>

Furthermore, a biopsy is often conducted to confirm a lipoma diagnosis. The diagnostic test can also help distinguish between a cyst, lipoma or liposarcoma. If the lipoma has blood vessels, the test may also be used to determine its location, depth, and whether it is pushing on any nerves or other tissues. 
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Treatment

Normally there are no medication or treatment guidelines for lipoma. However, certain procedures are documented to get rid of lipoma: 
&nbsp;

<ul>
	<li>Surgical Removal: It can be removed surgically. These lumps are normally removed for a few reasons: 
	&nbsp;</li>
</ul>

1. Cosmetic purposes

2. For clinical evaluation, to rule out the possibility of liposarcoma

3. When they are causing symptoms

4. The size of the lipoma continues to grow more than 2 inches.&nbsp; 
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A surgeon is responsible for removing the lipoma. The area where lipoma is present is adequately anesthetized then an incision is made to remove the lipoma. 
&nbsp;

<ul>
	<li>Liposuction can also be done. However, it is not as effective as a surgical removal because liposuction can not reach the lipoma beneath the muscle. 
	&nbsp;</li>
	<li>Percutaneous intralesional therapies are also one of the treatment plans followed by the dermatologists and include the administration of<a href="#accordion">[2]</a>: 
	&nbsp;</li>
</ul>

1. Sodium deoxycholate (associated or not to phosphatidylcholine) injections

2. Intralesional steroids combined with isoproterenol (beta-2 adrenergic agonist) injections. 
&nbsp;

<ul>
	<li>Usually, lipomas are cosmetic issues. However, it may get complicated if the lipoma grows in a sensitive location. Luminal obstruction or haemorrhage is typically reported in several cases<a href="#accordion">[1]</a>. 
	&nbsp;</li>
	<li>The procedure should be performed when the lipomas are minor rather than after they have grown larger to decrease the chance of them intruding on joints, nerves, and blood vessels, making excision more difficult and invasive. 
	 
	&nbsp;</li>
</ul>

The following condition may lead to the development of lipoma: 
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1. Genetics - It can run in the family.

2. Age - mostly it affects the age group of 40-60.

3. Obesity

4. Alcohol Abuse - over consumption of alcohol may lead to a type of lipoma called multiple symmetric lipomatosis.

5. Liver Disease

6. Glucose Intolerance 
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The prevention of lipoma is not postulated since it is inherited from the family. 
&nbsp;

Key Points

<ul>
	<li>Lipomas are benign, fatty lumps situated between the skin and muscle line, but not attached to muscle fascia. It is generally slow growing and harmless.</li>
	<li>Lipomas are most commonly found in the neck, shoulders, back, or arms. Some patients might have more than one.</li>
	<li>Lipomas are often roundish lumps that are soft and rubbery to the touch. Gentle pressing can be used to shift the lipomas slightly beneath the skin. Lipomas are not usually painful unless they affect joints, organs, nerves or blood vessels.</li>
	<li>A deep lipoma can put pressure on internal organs or nerves, resulting in discomfort. For instance, a person having a lipoma on or near the intestines may feel nausea, vomiting, and <a href="https://merisehat.pk/disease/constipation">constipation</a>.</li>
	<li>Even though the etiology of lipomas is unknown, several studies have shown a genetic connection; roughly 2-3% of lipomas have genetic abnormalities. Lipoma may also be produced in the region where the injury causes a significant impact</li>
	<li>Usually, lipomas are cosmetic issues. However, it may get complicated if the lipoma grows in a sensitive part. Luminal obstruction or hemorrhage is typically reported in several cases.&nbsp; 
	&nbsp;</li>
</ul>

[1] Todd A Nickloes DO. Lipomas. Background, Pathophysiology, Etiology

[2] Lipoma pathology - statpearls - NCBI bookshelf.

[3] Machol JA, Cusic JG, O'Connor EA, Sanger JR, Matloub HS. Spindle cell lipoma of the neck: Review of the literature and Case report. Plastic and reconstructive surgery.

[4] Moore K. Lipoma (skin lumps). Healthline.

[5] What are lipomas? American Family Physician.

[6] Lipoma - American Osteopathic College of Dermatology (AOCD).

[7] Our knowledge of orthopaedics. your best health. OrthoInfo.

[8] Lipoma (Fatty tumor): Causes, symptoms, diagnosis, and removal. WebMD.

[9] Papakonstantinou PE, Korkolopoulou P, Lassithiotakis D, Lolis ED. Giant angiolipoma of the arm in an elderly patient. Ann R Coll Surg Engl. 2016;98(6):e100-e102. doi:10.1308/rcsann.2016.0150