50Patient presenting with shoulder pain and significant functional limitation. Clinical findings are highly suggestive of adhesive capsulitis, including restricted passive external rotation and anteflexion, a typical course through the three phases of frozen shoulder, and associated risk factors such as diabetes. The patient is currently in phase 3 (thawing phase), with persistent stiffness and reduced pain compared to earlier stages.
The patient reports concern about a palpable swelling in the lateral upper arm, corresponding to the area of perceived pain.
Ultrasound examination demonstrates several indirect signs associated with adhesive capsulitis.
There is a small fluid collection in the biceps tendon sheath, likely communicating with the glenohumeral joint, suggesting mild intra-articular irritation.
The subacromial-subdeltoid (SASD) bursa appears mildly thickened, with subtle impingement observed between the bursa and the coracoacromial ligament during dynamic assessment.
The coracohumeral ligament (CHL) is markedly thickened at the level of the coracoid process, a well-described indirect sign of frozen shoulder.
Minimal neovascularization is observed in the subcoracoidal fat triangle.
There is moderate thickening of the glenohumeral capsule at the level of the axillary recess, further supporting the diagnosis.
Regarding the palpable swelling in the mid-humerus region, sonopalpation identifies a well-defined, oval, and homogeneous structure with normal echogenicity comparable to surrounding adipose tissue. There is no evidence of invasion into adjacent structures and no neovascularization. This is most consistent with normal subcutaneous fat or a benign lipomatous lesion. No suspicious features are identified.
1. Final diagnosis
Clinical adhesive capsulitis (frozen shoulder), likely phase 3 (thawing phase), with supportive ultrasound findings including CHL thickening and capsular changes.
2. Differential diagnosis
Consider rotator cuff-related shoulder pain or subacromial bursitis; however, the clinical pattern of global restriction strongly supports adhesive capsulitis. The palpable swelling is most consistent with benign subcutaneous tissue or lipoma.
3. Teaching points
Frozen shoulder is a clinical diagnosis; ultrasound findings are indirect and supportive. Key sonographic features include thickening of the coracohumeral ligament and axillary capsule. Discrepancy between severe functional limitation and relatively mild structural findings should raise suspicion for adhesive capsulitis.
4. Injury/disease information
Adhesive capsulitis is characterized by capsular inflammation and fibrosis, leading to pain and progressive stiffness. It typically evolves through three phases and may take 1–2 years to resolve. Risk factors include diabetes and prior shoulder pathology. Pain may radiate to the lateral upper arm, which can be mistaken for local pathology.
5. Additional note:
The palpable swelling in the upper arm shows benign ultrasound characteristics and does not appear to be the source of the symptoms. However, if there is growth, increasing pain, or other concerning changes, further evaluation is recommended.
Marc is founder of, and trainer at, SonoSkills. SonoSkills is an organization dedicated to MSK ultrasound education. He's also an MSK Sonographer at EchoConsult in Roermond, the Netherlands.
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