A paralabral cyst, or ganglion cyst, is a fluid collection arising from the shoulder’s ball and socket joint. Generally, these cysts don’t cause symptoms unless they push on essential structures near the shoulder, such as nerves or tendons. So, what is a paralabral cyst, and does it need treatment?

What is a paralabral cyst or ganglion cyst in the shoulder? 

Generally, any small fluid collection outside the shoulder joint is a paralabral cyst. These cysts originate from labral tears in the shoulder. The labrum is a type of cartilage in the shoulder that encircles the socket to make the shoulder more stable. These paralabral cysts are also called ganglion cysts in the shoulder. We also see these ganglion cysts in other body parts, such as the wrist or foot.

Causes of a ganglion cyst in shoulder  

shoulder labrum picture

The most common cause of a ganglion cyst in the shoulder is a labral tear. Labral tears, such as a SLAP tear, can occur due to trauma (dislocation), overuse, sport, and age. Sometimes, these labral tears produce fluid that pokes out of the joint, forming a ganglion cyst in the shoulder. 

Paralabral cyst shoulder symptoms 

shoulder pain in young fit male

Generally, ganglion cysts in the shoulder don’t cause problems. However, the cysts sometimes grow in size and can press on essential structures such as nerves or tendons. For example, ganglion cysts forming at the back of the shoulder can press on the suprascapular nerve, causing pain and weakness and wasting the muscles near the shoulder blade. Another example is the ganglion cyst growing at the bottom of the shoulder joint. This ganglion cyst causes pressure on the axillary nerve, leading to pain in the armpit and wasting of the shoulder deltoid muscle.

Also, the ganglion cyst arises from a labral tear, which can cause shoulder pain. 

One issue with a shoulder ganglion cyst is that pain from the ganglion (or the underlying labral tear) can be challenging to differentiate from other causes of shoulder pain: rotator cuff pain, frozen shoulder, or nerve pinching from the neck. Generally, pain from a cyst is constant and not made worse by movement. Also, muscle wasting is often seen if the cyst presses on a nerve. 

Diagnosis of a ganglion cyst in the shoulder

Generally, we diagnose ganglion cysts on imaging: MRI or ultrasound will show the cyst.

Paralabral cyst shoulder MRI

paralabral cyst shoulder on MRI

Overall, an MRI scan will clearly show the ganglion cyst in the shoulder and whether it compresses the nerve. Muscle wasting is often seen clearly on MRI, showing muscle atrophy and build-up of fat. Also, MRI can rule out other causes of shoulder pain.

Ultrasound will also show a shoulder ganglion cyst and the effects of muscle wasting. In addition, it can help with directing a needle for injection.

Treatment 

Overall, most ganglion cysts in the shoulder do not need treatment. This is because most cysts detected on MRI are incidental and not the cause of shoulder pain. Small cysts often don’t cause pain. However, larger cysts that put pressure on local structures need treatment.

Generally, we advise simple treatment first, such as physiotherapy and an injection. However, if simple therapies fail to work, surgery may be needed.

Paralabral cyst shoulder aspiration 

We try aspiration as the first-line intervention for a ganglion cyst of the shoulder. Aspiration means draining the ganglion cyst. Any procedure like aspiration should be done with ultrasound guidance. Generally, you should make sure your doctor is experienced in ultrasound procedures. Also, not just doctors are claiming to be experienced in ultrasound. Do your homework first before deciding on an ultrasound procedure.

Firstly, doctors inject a local anaesthetic to numb the skin and muscle above the cyst. Then, they use a larger needle to drain the cyst, which often contains a thick gel-like substance. Finally, a small dose of cortisone is added to the residual sac to prevent return. Sometimes, we inject the joint to reduce pain from the labral tear. After the injection, you should rest your shoulder for a week, followed by rehab from an experienced physiotherapist.

The pictures below show a ganglion cyst at the bottom of the shoulder joint. We drain the cyst using a needle under ultrasound  guidance. 

paralabral cyst shoulder
aspiration of paralabral cyst

Paralabral cyst surgery 

Sometimes, we suggest keyhole surgery for a ganglion cyst if simple treatments fail. This surgery will repair the labral tear and drain the paralabral cyst. Evidence indicates that surgery for paralabral cysts of the shoulder is effective in most cases but involves increased risk.

Other commonly asked questions relating to a paralabral cyst:

Will a paralabral cyst go away? 

Sometimes. Cysts may change in size with time. Some get bigger while others get smaller or disappear. 

Can paralabral cysts be cancerous? 

No. Cancerous growths have a different appearance to paralabral cysts on ultrasound or MRI. 

Do small paralabral cysts cause shoulder pain? 

Not usually. It’s the larger cysts that cause pain by pressure on other structures. Smaller cysts are generally asymptomatic. 

Final word from Sportdoctorlondon about paralabral cysts

Paralabral cysts are common. Most do not cause pain and do not need treatment. However, we recommend therapy if a cyst causes pain due to pressure on nerves or surrounding structures. An injection and aspiration should always be tried first. 

Related conditions:

Dr Masci is a specialist sports doctor in London. 

He specialises in muscle, tendon and joint injuries.