MyPACS.net: Radiology Teaching Files > Case 5550377

never visited ENCHONDROMA, PROXIMAL TIBIA
Contributed by: Radiology Residency Program Faculty & Staff.
Patient: 55 year old female
History:

55 year old female with elevated alkaline phosphatase, history of breast cancer diagnosed in 1991.

10/04/2005: Total Body Bone Scan

10/08/2005: Left Tibia/Fibula Radiographs

10/19/2005: MRI Left Tibia/Fibula w/ and w/o contrast

Images:[small]larger

Fig. 1

Fig. 2

Fig. 3

Fig. 4: Axial MR (a=PD, b=Fat Sat T2, c=Fat Sat T1, d=Fat Sat T1 postgadolinium)

Fig. 5: Coronal MR (a=STIR, b=T1, c=Fat Sat T1 postgadolinium)
Findings:

Fig. 1:Total Body Bone Scan shows a focal area of ovoid increased activity involving the proximal tibia.

Fig. 2 and 3: AP and Lateral radiographs of the proximal tibia show a subtle area of mixed lysis and sclerosis. The area of lysis is ovoid in appearance. The sclerosis is thin and curvilinear along the superior margin of the lysis.

Fig. 4: Axial MR (a=PD, b=Fat Sat T2, c=Fat Sat T1, d=Fat Sat T1 postgadolinium) -There is awell-defined multilobular lesion measuring 5.5 cm CC x 2.0 cm AP x 2.2 cm transverse. This is homogenously high in signal on fat saturation T2 and STIR imaging, and has intermediate signal on T1. The multiple lobules are separated by thin low signal intervening septa. On postcontrast images, the lesions shows peripheral enhancing rings and arcs. There is no medullary expansion, endosteal scalloping, cortical destruction, or adjacent marrow edema.

Fig 5: Coronal MR (a=STIR, b=T1, C=Fat Sat T1 postgadolinium) -There is awell-defined multilobular lesion measuring 5.5 cm CC x 2.0 cm AP x 2.2 cm transverse. This is homogenously high in signal on fat saturation T2 and STIR imaging, and has intermediate signal on T1. The multiple lobules are separated by thin low signal intervening septa. On postcontrast images, the lesions shows peripheral enhancing rings and arcs. There is no medullary expansion, endosteal scalloping, cortical destruction, or adjacent marrow edema.

Diagnosis: Enchondroma
Discussion:

Enchondroma

- common benign intramedullary neoplasm composed of mature cartilage
- 2nd most common benign bone tumor (after osteochondroma)

- well defined lytic lesion with chondroid matrix (rings and arcs calcifications)
- malignant transformation into chondrosarcoma
- Associated abnormalities: Ollier disease, Mafucci Syndrome, Metachondromatosis


Location:
- any bone formed by enchondral ossification can be involved
- Short, tubular bones of hands and feet: 60%
> Most common tumor of phalanges of the hand
- Long, tubular bones: 25-45%
> Metaphysis, proximal/distal end of diaphysis
> Femur: 17%
> Humerus: 7%
- Pelvis: <3%
- Spine, scapula, ribs: rare
- Size: usually < 3 cm

Radiographic Findings:
- Short, tubular bones: radiolucent lesion
- Long bones: Chondroid calcification ("rings and arcs," "popcorn type")
- Scalloped inner cortical margins
- Expansion of cortex without cortical break
- No periosteal reaction or soft tissue mass
- Progressive calcification

MR Findings:
T1WI
- Low to intermediate signal intensity
- Calcification: signal void

T2WI
- High signal intensity
- Calcification: signal void

Nuclear Medicine Findings:
Bone Scan
- usually "warm" or "hot"

Differential Diagnosis
Bone Infarct
Chondrosarcoma
Epidermoid Inclusion Cyst
Juxtacortical Chondroma

References:

1. Kaplan, PA. ... [et al.] Musculoskeletal MRI. 1st edition. Saunders, 2001.
2. Stoller, David W. ...[et al.] Diagnostic Imaging: Orthopaedics. Amirsys, 2004.

3. Resnick, D., Kransford, MJ. Bone and Joint Imaging. 3rd Edition. Elsevier Saunders, 2005.

Submitted by:

Aakash D. Singh, M.D. PGY-V Radiology Resident

Joseph A. Mendiola, M.D. - Radiologist
Mercy Medical Center

Comments:
No comments posted.
Additional Details:

Case Number: 5550377Last Updated: 08-10-2006
Anatomy: Skeletal System   Pathology: Benign Mass, Cyst
Modality: Conventional Radiograph, MR, Nuc MedExam Date: 10-04-2005Access Level: Readable by all users
Keywords: enchondromaACR: 454.3114

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