Disclaimer: The following case is for education purposes only and does not depict any actual person or patient.
A 17-year-old female presents with concern of her right shoulder seeming larger than her left shoulder. She reports no pain or physical limitations. She is a middle-distance track runner that states her coach and teammates notice her looking "stronger" in her shoulders due to offseason workouts. At a recent track meet, the family noticed that the right shoulder was larger than the left shoulder.
On physical exam, she has a noticeably larger right shoulder muscle mass than the left. There is noted swelling and no tenderness to palpation over the radial aspect of the proximal upper arm. She has full flexion/extension as well as abduction/adduction of the shoulder. She is otherwise neurovascularly intact.
X-ray obtained at the initial visit
MRI of the right shoulder illustrates the diagnosis
Clinical Approach
What clinical features make one consider a lipoma as the diagnosis?
In the cases of superficial lipomas, they rarely present with symptoms other than a visible swelling or enlargement of the area of concern. A lipoma typically presents as a discrete, mobile, solitary soft tissue mass, that in many cases is asymptomatic. The diagnosis is usually made by clinical examination and history and can be confirmed with diagnostic imaging.
What type of imaging is typically used to confirm the diagnosis?
In general, MRI can be used to confirm the diagnosis of a lipoma. Typically advanced imaging is performed with and without IV contrast when investigating an unknown mass lesion. A lipoma can be also detected using ultrasound, however, frequently the final report tends to be non-specific.
What other symptoms can be associated with a subdeltoid lipoma?
Although typically asymptomatic, a subdeltoid lipoma can present with symptoms of pain secondary to subacromial impingement. Additionally, subdeltoid lipomas can be associated with axillary nerve compression including loss of sensation over the lateral aspect of the shoulder.
Clinical Pearls
Subdeltoid lipomas are rare, but can occur in the pediatric population. They are typically asymptomatic, soft and mobile.
Initial presentation of a subdeltoid lipoma in a young healthy athlete may only be a complaint that one shoulder appears larger than the other.
Surgical excision is the ultimate treatment in a symptomatic lesion, which generally resolves symptoms and does not recur.
References:
Carbone S, Candela V, Passaretti D, Cinotti G, Della Rocca C, Giannicola G, Gumina S. Subdeltoid lipomas: a consecutive series of 13 cases. Musculoskelet Surg. 2012 May;96 Suppl 1:S53-6. doi: 10.1007/s12306-012-0190-7. Epub 2012 Apr 18. PMID: 22528845.