Age / Sex : 46 / M

Chief complaint: Left shoulder pain for 2 months

What is your impression?

Two weeks later, you can see the final diagnosis with a brief discussion of this case.

(답안은 한 개만 보내주시기 바랍니다)

Courtesy: 이인숙(In Sook Lee), 부산대학교병원 (Pusan National University Hospital)

Intraosseous ganglion

Discussion

Findings:

 On plain radiographs, an osteolytic lesion of geographic pattern with well-defined margin is seen in the inferior portion of scapular glenoid.

On axial CT scans, the lesion shows iso-density with adjacent muscle containing air-densities and adjacent bony cortex shows thinning and tiny disruption.

Axial T2-weighted MR image shows high signal intensity lesion with well-defined, lobulated margin. The lesion shows low signal intensity on coronal T1-weighted MR image and peripheral rim enhancement on fat-suppressed, contrast enhanced axial T1-weighted MR image.

Differential Diagnosis: Subchondral cyst, intraosseous ganglion, enchondroma

Diagnosis: Intraosseous ganglion

Discussion:

Synonyms for intraosseous ganglion (IOG) are juxta-articular bone cyst, subchondral/synovial bone cyst, ganglionic cystic defect of bone and capsulo-synovial intraosseous inclusion. Intraosseous ganglion are cystic lesions and usually occur in a subarticular location. It may be lined by a fibrous membrane and filled with mucoid, jelly-like material, but do not show a continuous layer of synovium. The exact incidence is unknown and a peak age is 40~50 decades with slight male predilection. Majority site is subarticular, in long bones often extending to the metaphysic. Several features have been used to differentiate IOG from geode(subchondral cyst): age, IOG occuring in patents less than 30 years of age ; presence of joint disease, patients with IOG showing no evidence of joint disease, or abnormality restricted to the site of the cyst; the location of the cysts, degenerative cysts are found in the weight-bearing regions of the acetabulum and IOG more medially in the acetabulum and in the femoral head.

On plain radiographs, typically osteolytic, septated or trabeulated lesions located eccentrically in juxta-articular bone. Lesion size is a 6mm ~ 120mm, elongated in the long axis of the bone. More than 50% of cases show no evidence of degenerative joint disease. A geographic pattern of bone destructions is unusual with the majority showing a sclerotic margin. Zone of transition with normal bone is narrow. There is a range of cortical responses(expansion, destruction, endosteal scalloping), and fracture may occur, but there is rarely periosteal rection. No matrix mineralization is idenfitied. A soft tissue mass is rarely seen(4%).

CT scans show lobular, sclerotic border and maybe cortical thining or deficiency. Gas can be seen within the lesion if there is communication with the joint.

On MRI, this lesion shows lobular and well defined margin. Internal signal is often slightly heterogeneous but predominately of fluid signal intensity. T1-weighted image shows isointense, but occasional hyperintensity due to increased protein component. T2-weighted or STIR image shows homogeneous fluid signal intensity. On contrast enhanced image, it may be enhancement in the rim or occasionally heterogeneous enhancement throughout the lesion.

References:

•  Imgaing of bone tumors and tumor-like lesions A. M. Davies ∙ M. Sundaram ∙ S. L. J. James Springer-Verlag Berlin Heidelberg 2009


• Dähnert W. Radiology review manual. Lippincott Williams & Wilkins. (2007)


• H. J. Williams(2004) Imaging features of intraosseous ganglia: a report of 45 cases Eur Radiol (2004)