From the Guidelines
Lipomas typically grow in the subcutaneous tissue just beneath the skin, most commonly appearing on the neck, shoulders, back, abdomen, arms, and thighs. These benign fatty tumors can also develop in deeper tissues such as muscles or organs, though this is less common 1. According to the UK guidelines for the management of soft tissue sarcomas, lipomas are the most common soft tissue mass of the limbs and torso seen in primary care, and they tend to be benign 1.
Some key characteristics of lipomas include:
- They form when fat cells multiply abnormally and cluster together, creating soft, movable lumps that usually feel doughy to the touch
- They tend to grow slowly and rarely cause pain unless they press on nearby nerves or contain blood vessels
- Most lipomas remain small (less than 2 inches in diameter), though some can grow larger
- Their development is linked to genetic factors, and they occur more frequently in adults between 40-60 years of age
It's worth noting that while lipomas are generally harmless and don't require treatment, those that are painful, growing rapidly, or causing cosmetic concerns can be removed through surgical excision or liposuction procedures. The British Sarcoma Group has produced guidance to help primary care practitioners and ultrasonographers identify which lipomatous masses identified on ultrasound need referral to sarcoma unit, and those which can be managed by local services 1.
From the Research
Locations of Lipoma Growth
Lipomas are benign tumors that can grow in various parts of the body. The locations where lipomas typically grow include:
- Head
- Neck
- Trunk
- Extremities, such as the upper arm, back, thigh, and shoulder 2, 3 Specifically, studies have found that:
- Lipomas can range from 1 to 15 cm in diameter and can be found on the head, neck, trunk, and extremities 2
- Large lipomas (equal to or greater than 5 cm in diameter) can be found in the shoulder, upper arm, back, and thigh 3
- The shoulder region is a common location for large lipomas, with three lipomas larger than 10 cm in diameter found in this area 3
Characteristics of Lipoma Growth
Lipomas are characterized by high signal intensity on T1- and T2-weighted images on magnetic resonance imaging (MRI) 3. They can be located between retaining ligaments at the periphery of the tumor, and these ligaments can be identified by MRI 3. The growth of lipomas can be managed through various treatments, including liposuction, excision, and injection therapy 2, 3, 4, 5, 6.