DEFINITION AND PATHOGENESIS
- A secondary juxta-articular cyst associated with an inflammatory or non-inflammatory (degenerative) arthridity
- One of the four cardinal radiographic findings in arthritis: joint space narrowing, subchondral sclerosis, osteophyte formation, and subchondral cysts
- Symptoms of degenerative joint disease dominate
- Subchondral lucency with sclerotic rim
- MRI reveals lesion filled with fluid
- Mucinous material within the cyst
- Synovial lining to the cyst
DIFFERENTIAL CLINICOPATHOLOGIC DIAGNOSIS
- Same as intraosseous ganglion cyst, although associated radiologic findings give supporting diagnostic evidence
DISEASE COURSE AND TREATMENT
- Non-steroidal anti-inflammatory Rx, activity modification, assistive devices, ultimately, total joint replacement
- Gas containing cysts of the sacrum or ilium ? vacuum phenomena in the SI joint reportedly asymp-tomatic and an incidental finding
Fisher ER, Gruhn J, Skerrett P: Epidermal cyst in bone. Cancer 11:643-8,1958.
Mirra JM: Cysts and cyst-like lesions of bone: Subchondral cyst. In Mirra JM, Picci P, Gold RH (eds): Bone Tumors: Clinical, Radiologic and Pathologci Correlations. Philadelphia, Lea & Febiger, 1989, p 1312.
Mollan RA, Wray AR, Hayes D: Traumatic epidermoid cyst of the ulna: report of a case. J Bone Joint Surg 64B:456-7,1982.
Monu JUV, Crotty JM, Pope TL, Jr: Intraosseous pneumatocyst of the iliac bone. Clin Orthop 330:190-2, 1996.
Silas SI, Resnik CS, Levine AM: Bilateral primary cystic arthrosis of the acetabulum. A case report. J Bone Joint Surg 78A:775-8, 1996.