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it might be a tumor geyser sign cover

It Might Be a Tumor

Case Introduction

A 54 year old male presented to the Emergency Department (ED) with a chief complaint of a worsening lump on his shoulder. He states it’s painful and is concerned he has cancer. He denies any additional complaints. He states the duration is about 3 or 4 weeks. Other than smoking, he denies any medical history or injuries to his shoulder.
On physical exam, there is a firm, non-tender, non-mobile mass on the superior part of the patient’s left shoulder. It is without erythema or warmth. The patient’s shoulder exam is notable for intact range of motion and strength. He has a positive Hawkins test and Empty can test.
Point of care ultrasound identifies a fluid-filled structure overlying the acromioclavicular (AC) joint. Initial radiographs demonstrated the so-called “geyser” sign. This is a finding of synovial fluid expressed through the AC joint consistent with a rotator cuff tear.

Geyser Sign Discussion

Geyser’s sign, first described in the 1980s, is characterized by a flow of synovial fluid from the glenohumeral joint into the acromioclavicular (AC) joint to form a synovial cyst or fluid collection above the joint space.1Maziak N, Plachel F, Scheibel M, et al. Acromioclavicular joint cyst formation in a patient with rotator cuff-tear arthropathy: a rare cause of shoulder discomfort. BMJ Case Rep. 2018 Sep 27;2018. The name is derived from the term geyser in which fluid erupts through a tight space under pressure. It is typically seen with chronic rotator cuff tares and moderate to severe forms of shoulder arthritis.

Clinical exam of the geyser sign
A large, golf-ball sized mass is seen above the left AC joint
Classically, it presents as a slow-growing “pseudotumor” above the AC joint. In the case of our patient, he presented thinking he had a tumor on his shoulder. In patients with chronic rotator cuff tears and glenohumeral arthritis, the inferior aspect of the AC joint capsule can be disrupted. Once that happens, the high pressure of the shoulder joint fluid slowly flows superiorly. This synovial fluid can originate from both the glenohumeral joint and subacromial bursa. They can be classified as type 1 if the source is the AC joint and type 2 if the source is rotator cuff arthropathy.
Shoulder xray geyser sign, AC joint OA
On xray, you can see a high riding humeral head where it may even approach the inferior acromion. This is a sign that the rotator cuff is chronically torn and retracted. There are also arthritic changes as the AC joint and the silhouette of the geyser is seen above.
The differential diagnosis includes synovial cyst (correct attribution in this case), abscess (excluded by history, exam, ultrasound), pseudoaneurysm (excluded by lack of flow on color doppler), malignancy (excluded by multiple imaging modalities), foreign body (excluded by history primarily), epidermoid cyst (excluded by ultrasound) and lipoma (excluded by ultrasound)
Shoulder ultrasound geyser sign
Large hypoechoic, fluid filled and well circumscribed structure above the left AC joint (not our patient).1Case courtesy of Maulik S Patel,, rID: 160177
There are no clear guidelines for treating this condition as it may be strictly cosmetic in nature or associated with pain and weakness. Management is directed at the underlying condition such as rotator cuff repair or treating the shoulder arthropathy. Aspiration is contra-indicated due to risk of introducing infection and a high rate of recurrence. If the cyst is big enough or the patient is concerned, orthopedic surgery can consider surgical interventions such as distal clavicular excision and subacromial bursectomy.2Kontakis, George M., Theodoros H. Tosounidis, and Apostolos Karantanas. “Isolated synovial cyst of the acromio-clavicular joint associated with joint degeneration and an intact rotator cuff.” Acta Orthopaedica Belgica 73.4 (2007): 515.
Shoulder MRI Geyser Sign
Shoulder MRI showing degeneration of the acromioclavicular joint with large amount of glenohumeral joint fluid "erupting" superiorly through the acromioclavicular interval into the subdeltoid bursa.2Case courtesy of Christof Igler,, rID: 53907
Shoulder CT - Left shoulder CT with geyser sign
CT of the patients left shoulder also shows a high riding humeral head, AC joint arthritis and the geyser sign above

Case Conclusion

The patient was discharged from the ED with primary care follow up and intent to obtain an MRI. PCP note 1 week later states the patient admitted discomfort and lump had been progressive over two months instead of the 3 weeks initially reported. Patient was a poor candidate for MRI due to retained metallic fragments in the occiput. CT was obtained instead. This confirmed a low-density soft tissue mass cephalad to an osteoarthritic AC joint, and further demonstrated a high riding humeral head, with advanced fatty atrophy of the supraspinatus muscle (not pictured). After missing two appointments with orthopedic surgery, and one with general surgery, the patient was considered lost to follow-up

3 Key Points

  1. Not all masses are tumors!
  2. Geyser sign is an unusual physical exam finding consistent with chronic rotator cuff tear
  3. Treatment directed at underlying condition, guidelines are not widely established
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