Age / Sex : 22 / F

Osteoblastoma

Discussion

Findings:

CT :

Spine CT of a 19-year-old male presenting an about 2.6 x 1.8 x 2 cm sized
expansile osteolytic bone tumor in left neural arch (pedicle and lamina) of T1,
with cortical thining and breakage, and central irregular calcification or
ossification.

And also noted sclerotic change to adjacent vertebral body of T1.

MRI :

Spine MRI demonstrating a multilobulated expansile bone tumor in left
neural arch (pedicle and lamina) of T1.

This lesion reveals intermediate SI with central low SI on T1WI, low SI on
T2WI and strong contrast enhancement on fat sat contrast-enhanced T1WI. 

There are surrounding soft tissue infiltration and bone marrow edema.

Differential Diagnosis:

1.  Osteoid osteoma

2.  Aneurysmal bone cyst

3.  Bone metastasis.

4.  Osteosarcoma.

5.  Chondrosarcoma

6.  Infection

Diagnosis: 

Osteoblastoma

Discussion:

Osteoblastoma –

I.       an uncommon osteoid tissue-forming primary
neoplasm of the bone.

II.      It has histologic manifestations similar to
those of osteoid osteoma.

III.     accounts for 1–3 % of all primary bone tumors,
with a male-female ratio of 2.5 : 1.

IV.    between 32% and 46% of osteoblastomas involve
the spine (mainly the posterior elements).

V.     80-90 percent of osteoblastomas manifest in
the 2nd and 3rd decades of life.

Radiographic features

Conventional radiography and CT

I.       typically larger than 2 cm in size.

II.      predominantly lytic and expansile

III.     reactive sclerosis adjacent to the lesion

IV.    internal matrix mineralization

V.     cortical expansion, sometimes with cortical
destruction

VI.    surrounding sclerosis or periostitis in up to
50%

MRI

I.       T1WI : low / intermediate signal intensity,
with areas of decreased intensity that correspond to mineralization

II.      T2WI : intermediate / high signal intensity,
low signal areas of bone matrix, peritumoral edema may involve adjacent bones
and soft tissues

III.     T1WI with contrast enhancement : variable
enhancement, peritumoral
edema may enhance  

Treatment and prognosis

I.       Curettage with bone grafting. Preoperative
embolization may be useful.

II.      Percutaneous ablation

III.     The recurrence rate is 10%–15%.

References:

1.     Ross, Brant -
Zawadzki, Moore, Crim, Chen, Katzman : Diagnostic Imaging SPINE, Amirsys,  IV:1-22 to IV:1-25

2.     Resnick, Kransdorf : Bone and
Joint Imaging, 3^rd edition, Elsevier Saunders, 2005, 1126-1130

3.     Rodallec MH, Feydy A,
Larousserie F, Anract P, Campagna R, Babinet A, Zins M, Drapé JL. Diagnostic
imaging of solitary tumors of the spine: what to do and say. Radiographics.
2008;28(4):1019-41.

4.    Murphey MD, Andrews CL, Flemming DJ, Temple HT, Smith WS, Smirniotopoulos JG.

From the archives
of the AFIP. Primary tumors of the spine: radiologic pathologic

correlation.
Radiographics. 1996;16(5):1131-58.