Intramuscular Lipoma of the Supraspinatus Causing Impingement Syndrome

Abstract

Impingement syndrome is a common ailment of the shoulder, particularly in individuals who perform repetitive overhead activities, such as athletes and laborers. Patients typically report progressive shoulder pain often exacerbated by flexion and abduction and may demonstrate a classic painful arc of motion. This article describes a case of a 45-year-old man with signs and symptoms consistent with impingement syndrome. Workup revealed a well-circumscribed, homogeneous lesion within the supraspinatus muscle on magnetic resonance imaging. The patient underwent uncomplicated marginal excision of the mass with a final diagnosis of benign lipoma. Lipomas represent one of the most common soft tissue tumors, although there are no reports of an intramuscular supraspinatous lipoma causing impingement syndrome. In our case, there were no findings on history, physical examination, or radiographs that would place neoplasm high on a differential. Magnetic resonance imaging provided the crucial information necessary to narrow the differential diagnosis and formulate a preoperative plan. Marginal resection of the mass was curative in this patient, as he remained pain free and regained excellent motion postoperatively.

An unusual cause of subacromial impingement: A collagenous fibroma in the bursa

“…There are 2 reported cases in the literature of intramuscular lipomas of the supraspinatus muscle presenting as impingement syndrome. 1,3 Our case illustrates the point that primary outlet impingement in a young patient is extremely rare and other explanations should be sought for a young patient presenting with spontaneous cuff pain. Cuff pain is primarily associated with instability in young patients.…”

Arthroscopic Marginal Resection of a Lipoma of the Supraspinatus Muscle in the Subacromial Space

“…There are few reports in the literature about painful intramuscular lipomas involving the supraspinatus muscle. 4,6 Although lipomas represent one of the most common soft-tissue tumors, 8,9 predominantly in the subcutaneous tissues, they can be found uncommonly inside the muscular tissues, converting them into a cause of shoulder impingement syndrome. According to Bigliani and Levine, 2 an intramuscular lipoma is considered an intrinsic process of primary etiology for shoulder pain that has to be excluded from other causes of similar symptoms such as calcified tendinitis, glenohumeral instability, suprascapular nerve neuropathy, degenerative joint disease, biceps tendinitis, or frozen shoulder.…”

“…4 Complete surgical marginal excision is the treatment of choice for deep lipomas. 5 For the uncommon case of a supraspinatus muscle lipoma, the operative approach can be over the trapezius fascia 6 or transdeltoid muscle. 7 We describe complete marginal excision of a small lipoma in the supraspinatus muscle in the subacromial space by means of an arthroscopic approach.…”

Anatomical Distribution of Intramuscular Lipomas

“…The biceps brachii [59], the subscapularis [60], the deltoid [61][62][63], the supraspinatous [64,65], the infraspinatus [66] and the brachioradialis [67] may be involved, while localization adjacent to the proximal radius may be complicated by symptomatic radial nerve compression [68][69][70]. Involvement of the tensor fascia lata has also been reported [71] as well as of the vastus lateralis [51] and of the gluteus maximus and gastrocnemius [14].…”