What is the recommended management plan for a young patient with a bone cyst of the left shoulder, possibly due to trauma or injury?

Management of Bone Cyst of the Left Shoulder

For a young patient with a bone cyst in the left shoulder, begin with standard radiography (AP views in internal and external rotation plus axillary or scapular-Y view) to characterize the lesion, followed by MRI if diagnosis remains uncertain, then proceed with curettage plus local adjuvants and bone grafting as definitive treatment for symptomatic or at-risk lesions. 1

Initial Diagnostic Workup

Mandatory Radiographic Evaluation

• Obtain standard three-view radiographs as the first-line imaging modality, including anteroposterior views in internal and external rotation plus an axillary or scapular-Y view to assess bony anatomy and characterize the lesion. 1
• Radiographs will demonstrate whether the cyst is lytic, expanded, or multiseptate, and help differentiate simple bone cysts from other entities like aneurysmal bone cysts or giant cell tumors. 2

Advanced Imaging When Needed

• If radiographs are indeterminate or cannot fully characterize the lesion, proceed to MRI without contrast, which provides superior soft tissue detail and can demonstrate rim enhancement patterns characteristic of simple bone cysts. 2
• MRI is particularly valuable for identifying fluid-fluid levels (suggesting aneurysmal bone cyst), hemorrhagic components, and the relationship of the cyst to adjacent structures including the glenoid and rotator cuff. 2, 3
• CT without contrast may be obtained if fracture characterization is needed or to better delineate septations and calcifications, though it is less useful than MRI for soft tissue evaluation. 1

Treatment Algorithm Based on Cyst Characteristics

For Active or Symptomatic Cysts

• Perform open curettage (manual plus motorized high-speed burr) combined with local adjuvants and bone grafting to fill the void as the standard definitive treatment. 4
• Calcium phosphate cementation is an effective bone substitute that allows early mobilization and return to activity. 2
• This approach addresses the risk of pathologic fracture, promotes cyst healing, and minimizes recurrence rates. 5

For Lesions at Risk of Pathologic Fracture

• Consider percutaneous cannulated screw insertion for continuous decompression and drainage, which can promote cyst healing while preventing pathologic fracture in select cases. 5
• This minimally invasive approach may be appropriate for unicameral bone cysts that are at high risk for fracture but have not yet fractured. 5

Alternative Approaches for Difficult Anatomical Locations

• If the cyst involves anatomically challenging areas near the glenoid where surgical access is limited, consider percutaneous injection of sclerosant agents or demineralized bone matrix with autologous bone marrow concentrate. 4
• Selective arterial embolization may be used pre-operatively to reduce bleeding risk in large, vascular lesions or as primary treatment in certain cases. 4

Post-Treatment Management

Rehabilitation Protocol

• Initiate early mobilization following surgical treatment to restore shoulder function and prevent stiffness. 2
• Implement range of motion exercises focusing on external rotation and abduction once adequate healing has occurred. 6
• Avoid overhead pulleys initially, as uncontrolled abduction may stress the surgical site. 6

Follow-Up Surveillance

• Monitor for cyst recurrence with serial radiographs, as bone cysts can have unpredictable behavior with variable recurrence rates depending on treatment method. 4
• Document neurovascular status at each follow-up visit to ensure no compromise from the lesion or treatment. 7

Critical Pitfalls to Avoid

• Do not assume the diagnosis without tissue confirmation, as lytic lesions in the scapula can represent simple bone cysts, aneurysmal bone cysts, or giant cell tumors—open biopsy may be necessary for definitive diagnosis. 2
• Do not delay treatment of symptomatic cysts or those at high fracture risk, as pathologic fractures complicate management and prolong recovery. 5
• Ensure complete evaluation of the shoulder joint and surrounding structures, as rotator cuff pathology may coexist and require concurrent management. 2
• In young patients, assess for growth plate involvement if the cyst is near physeal regions, though this is less common in shoulder lesions. 7