605 - A Rare Cause of Refractory Shoulder Impingement: Point-of-Care Ultrasound Diagnosis of a Large Post-Operative Intramuscular Lipoma

Friday, February 20, 2026

5:00 PM - 6:30 PM AST

Co-Author(s)

KH

Kristen Hines, BS

Medical Student
Harvard Medical School
Hamden, Connecticut, United States

Presenting Author(s)

RJ

Rafael Jimenez, MD

Resident Physician
Spaulding Rehabilitation Hospital
Charlestown, Massachusetts, United States

Co-Author(s)

CE

Christine Eng, MD

Attending Physician, Sports Medicine
Spaulding Rehabilitation Hospital/Massachusetts General Hospital
NA, Massachusetts, United States

Submitter(s)

KH

Kristen Hines, BS

Harvard Medical School
Hamden, Connecticut, United States

Case Diagnosis: Large post-operative intramuscular lipoma in coracobrachialis and short head of biceps brachii.

Case Description: 61-year-old female with a history osteoarthritis, osteoporosis and a right total shoulder arthroplasty (TSA) 10 years ago prior, presents to the clinic for increasing right shoulder pain. She was previously diagnosed with shoulder impingement and completed a course of physical therapy without resolution of symptoms. On representation to clinic, she was reevaluated. Her exam showed a soft tissue prominence with intact sensation, full strength, and limited internal rotation in the right upper extremity. In-office diagnostic ultrasound of the right upper extremity revealed a large echogenic, well-circumscribed mass, with a lack of normal muscle architecture, disorganized fibers, and without apparent infiltration to surrounding tissues within the coracobrachialis. She had developed this mass since the TSA, and it gradually had causing increasing pain for 5 years. MRI revealed a 7.5 cm x 5.8 cm x 16.5 cm lipoma in the coracobrachialis and along the short-head of biceps. The mass was surgically removed..

Discussions: In this case, the shoulder impingement was caused by a lipoma that had grown significantly, limited weight-bearing and exercise, prompting excision. Lipomas that are a less common cause of shoulder impingement and should be removed if impeding mobility and to prevent atrophy and impairment of the limb. Diagnostic ultrasound is a crucial in-office diagnostic tool for atypical shoulder impingement.

Conclusions: In patients with shoulder impingement that did not obtain relief through physical therapy, further imaging with ultrasound can further characterize the cause of shoulder impingement. Additionally, this case represents a rare consideration for the differential diagnosis of post-op shoulder and upper arm pain.