Intramuscular Ganglion Cyst: A Common Lesion in an Unusual Location

Case Report

Austin J Clin Case Rep. 2015; 2(3): 1077.

Intramuscular Ganglion Cyst: A Common Lesion in an Unusual Location

Najjar S* and Nasser H

Department of Pathology, Prince Sultan Military Medical City, Saudi Arabia

*Corresponding author: Najjar S, Department of Pathology and Laboratory Medicine, King Faisal Specialist Hospital and Research Center, Prince Sultan Military Medical City, MBC10, Saudi Arabia

Received: July 06, 2015; Accepted: September 05, 2015; Published: September 10, 2015


Ganglion cysts represent the most common benign soft tissue lesion of the hands and wrists. When arising in their characteristic locations, their diagnosis and treatment is easy; however, when arising in atypical locations they pose a diagnostic dilemma. We present a case of intramuscular ganglion cyst arising in the extensor digitorum muscle of the left arm. Due to its unusual location and radiological characteristics it was suspected as being an intramuscular myxoma, and was treated with wide excision. We believe that recognizing this entity in the differential diagnosis of intramuscular cystic lesions is important for proper management.

Keywords: Ganglion cyst; Intramuscular cyst; Radiological


Ganglion cysts (GCs) are non-neoplastic pseudocysts that have no true epithelial lining and are filled with gelatinous material composed mainly of hyaluronic acid. Their definite etiology is still unknown. They may be secondary to degenerative changes and chronic damage that leads to liquefaction and cyst formation. This is followed by proliferation and formation of a fibrotic and compact wall arising from the surrounding connective tissue [1] The gelatinous material has also been proposed to be produced by injured mesenchymal cells [2].

GCs most commonly originate from joints, particularly the scapholunate joint of the wrist, and to a lesser extent form tendon sheathes in young patients. However, they have been reported in many different sites and so have a variety of clinical presentations depending on their anatomical location.

GCs arising in atypical locations present a diagnostic challenge and might get misdiagnosed. They have been reported to originate from cartilage, nerves, and muscles. Intra articular ganglion cysts of the knee mainly involve the tendon sheath or joint capsule and infrequently the menisci, and anterior and posterior cruciate ligaments [3-5]. Somewhere reported to occur intraosseously in the distal epiphysis of the tibia and from peripheral nerve sheath particularly the common perineal nerve [6]. Involvement of other nerves including the radial, ulnar, median and sciatic nerves have also been reported [7]. Cases of multiple ganglion cysts involving unusual sites like the temporo mandibular joint affecting young patients, the so called cystic ganglion sis, might indicate a genetic susceptibility and give new insights to the pathogenesis of this lesion [8].

Case Presentation

Clinical summary

A 46-year-old male patient, medically free, presented complaining of a left upper arm swelling of six months duration. On physical examination, a bulging well-circumscribed mass was noted in his elbow region. There was no range of motion restriction, weaknesses or paresthesia.

Radiological findings

Multiplanar MRI of the left elbow joint showed a multiloculated multicystic lesion at the extensor digitorum muscle from the level of the radial head showing thin peripheral wall and septal enhancement of the mass without internal solid enhancement confirming its cystic nature (Figure 1). The tendons and ligaments around the elbow joint were normal and unaffected. No connection to the elbow joint was identified and the diagnosis of intramuscular myxoma was suggested.