Musculoskeletal Cases 51-75

1. Musculoskeletal Cases 51-75

2. Case directory

3. Case 51

4. Fibrolipomatous hamartoma(neural fibrolipoma) • Case findings: • Axial proton-density MR image of the wrist: heterogenous mass within the carpal tunnel • Mass contains fat, displaces the flexor tendons and causes bowing of the flexor retinaculum • Tumor of fatty and fibrous tissue • MC involves median nerve in the carpal tunnel, LC tibial nerve • Associated with macrodystrophia lipomatosa • Gradual infiltration of nerves by fibrofatty tissue (MC median nerve)

5. Case directory Macrodystrophia lipomatosa and fibrolipomatous hamartoma

6. Case 52

7. Fibrous dysplasia • Case findings: • XR: large expansile lesion of 12th posterior rib • DDX: • Fibrous dysplasia • Plasmacytoma • Metastatic disease • Chondrosarcoma

8. Case directory Fibrous dysplasia • Radiolucent expansile medullary lesion (but may replace both cancellous and cortical bone) • Ground glass: due to dysplastic microtrabeculae • Well-defined sclerotic margins, endosteal scalloping • Either monostotic (80%) or polyostotic • McCune-Albright syndrome: • Polyostotic fibrous dysplasia • Cafe au lait spots • Precocious puberty

9. Case 53

10. Case directory Dermatomyositis • Linear and confluent calcifications in soft tissues (at pressure points in the extremities, axillae, hands and inguinal regions) • Lacy, reticular subcutaneous calcium deposit encasing the trunk • Fibrosis leads to contractures and deformities of the trunk

11. Case 54

13. Case directory Hemophilic arthropathy • Hemorrhage produces synovitis(pannus formation) • Features: • Overgrowth of epiphysis • Widening of intercondylar notch (knee) • Hemosiderin deposition • Joint effusion • DDX: • Juvenile RA

14. Case 55

15. Lipohemarthrosis • Mixture of fat and blood in a joint cavity following trauma • Presence of a fat-fluid level is nearly diagnostic of a fracture, even when that fracture is radiographically occult

16. Posterior dislocation of the right hip with blood and fat filling the acetabular fossaWhite arrow indicates fat layering upon blood (black arrow)

18. Case directory Lipohemarthrosis of glenohumeral joint: globular focus of fat layering upon a small amount of blood

19. Case 56

20. Onchronosis (alkaptonuria) • Spondylitis and arthritis of large joints (knees, shoulders, hips) • Deposition in cartilage  synovial thickening • Spine: • Degenerative disc disease • Resembles ankylosis spondylitis • Disc space calcification • Pathognomonic: seen in younger patient • Universal disc calcification • DJD of root joints (hips and shoulders)

21. Case directory LS and Pelvis: Severe osteoporosis Widespread discal calcifications with disc space loss Sclerosis of SI joints bilaterally Ossification in acetabular labra of the hips

22. Case 57

24. Tarsal coalition • Diagnosis: subtalar coalition (talocalcaneal) • Case findings: • Lateral ankle: • C sign: C-shaped line formed by medial outline of talar dome and inferior outline of sustentaculum tali • CT ankle: • Bony bridge between talar dome and sustentaculum tali • Types: cartilage, fibrous tissue, osseous • MC calcaneonavicular, LC talocalcaneal

25. Diagnosis: calcaneonavicular coalition Anteater nose sign: enlargement of the anterosuperior portion of the calcaneus (arrow) Tarsal coalition

26. Case directory Tarsal coalition • Diagnosis: talocalcaneal coalitition • Osseous excrescence or "beak" protruding from anterior talus (arrow)

27. Case 58

29. Case directory Multiple hereditary exostoses (MHE) • Multiple bilateral and symmetrical osteochondromas • MRI may be used to assess cartilaginous cap • Development of pain attributable to an exostosis is worrisome from sarcomatous degeneration • Complications: • Fracture • Vascular injury • Neurologic compromise • Bursa formation • Malignant transformation

30. Case 59

31. Case directory Jaccoud’s arthritis • Case findings: • Radial deviation at radiocarpal joint • Ulnar deviation at the MCP joints • Capsular erosions at several metacarpal heads • Deforming nonerosive arthropathy that may appear after repeated attacks of arthritis in patients with rheumatic fever • Asymptomatic, reversible joint deformities

32. Case 60

33. Medial weight-bearing surface Superior weight-bearing surface

34. Osteoarthritis • Features: • Joint space narrowing • Subchondral sclerosis • Marginal osteophyte formation • Subchondral cysts • Hands • Not due to mechanical stress • MC involves 1st MCP of thumb, DIP

35. Case directory Secondary degenerative arthritis • Atypical location: CPPD (knee) • Atypical appearance: marked DJD of one hip (RA, AVN) • Atypical age • Types: • Trauma, infection • AVN • RA, CPPD • Hemophilia

36. Case 61

38. Case directory Gout • Asymmetric, monoarticular • MC involves 1st MTP • Olecranon bursitis common • Tophi rarely calcify • Features: • Juxta-articular erosions (overhanging edges) • No joint space narrowing (JSN a late finding) • Soft tissue swelling • No osteoporosis

39. Case 62

41. Rheumatoid arthritis • Features: • Bilaterally symmetrical • Proximal joints: MCP, PIP, ulnar styloid • Periarticular demineralization • May lead to secondary DJD: • Marked narrowing of joint space • Intact articular cartilage • Little or no sclerosis

43. RA foot: 5th MTP early (MC)

44. Case directory RA of hips: marked JSN, little sclerosis

45. Case 63

46. Case directory Systemic lupus erythematosus • Subluxation without erosions • DDX: SLE, Jaccoud's arthropathy • AVN: intrinsically or secondary to steroids

47. Case 64

49. Psoriatic arthritis • Case findings: • Hand: • Periostitis (arrows) • STS of 3rd digit • Erosions at margin of DIP joint • Fingers: • Marginal and central erosions (arrows) • Intra-articular ankylosis • Flexion contractures at DIP joints

50. Psoriatic arthritis • MC involves DIP (hands > feet) • Acro-osteolysis (pencil-in-cup deformity) • Soft tissue swelling (sausage digit) • No osteoporosis • Asymmetric SI involvement (like IBD, TB) • Spine: non-marginal syndesmophytes