Age / Sex : 17 / M

Age/Sex: 17/M

Chief complaint : Rt. shoulder pain    (2 yrs ago)

osteoblastoma

Discussion

Findings:

 C-spine AP and lat.: Questionable bony mass in right lateral mass of C6

CT: Expansile osteolytic bone lesion in right pedicle and lamina of C6.

        cortical thining, central irregular calcification or ossification in this lesion.

        compression of the right transverse foramen.

MRI:  Lobulated mass lesion is noted at right pedicle, posterior element.

           This lesion reveals Iso to slightly high SI with central low SI on T1WI,

low SI on T2WI and heterogenous enhancement.

           Surrounding soft tissue infiltration and enhancement. 

Differential Diagnosis:  

1.       Osteoid osteoma

2.       Aneurysmal bone cyst

3.       Osteosarcoma (aggressive osteoblastoma)

4.       Ewing’s tumor

Diagnosis:  

   Osteoblastoma

Discussion:

•          1~2% of all benign bone tumor

•         Histologically similar to osteoid osteoma

•         >1.5cm in diameter

•         Age; adolescent(20~70yrs)

•         M:F=2:1

•         Site; spine(33%) -posterior element,   

                                  extension into vertebral body

       long bone diaphysis(26%)-femur ½

       hand, foot, pelvis, rib, skull, scapula, clavicle

•         Three radiologic pattern :;

     1) central radiolucent area and surrounding  

       osseous sclerosis

        - similar to the radiologic appearance of   

         osteoid osteoma, but larger than 1.5cm

     2) expansile lesion with multiple small

       calcifications and a peripheral sclerotic rim

        - m/c appearance of spinal osteoblastoma

    3) osseous expansion, bone destruction,

        infiltration of surrounding soft tissue,

        and intermixed matrix calcification

        - aggressive appearance

•         MR

    1) T1WI : low/intermediate SI

    2) T2WI : intermediate/high SI

                  low signal areas of bone matrix

                  peritumoral edema may involve

                  adjacent bones and soft tissues

    3) enhanced T1WI : variable enhancement

                  peritumoral edema may enhance   

References:

1.MD Murphey, CL Andrews, DJ Flemming, HT Temple, WS Smith, and JG  Smirniotopoulos: From the archives of the AFIP. Primary tumors of the spine: radiologic pathologic correlation. RadioGraphics 1996; 16: 1131-1158.

2.HM Kroon and J Schurmans. Osteoblastoma: clinical and radiologic findings in 98 new cases. Radiology 1990; 175: 783.

3.Ross, Brant-zawadzki, Moore, Crim, Chen, Katzman: Diagnostic imaging SPINE IV:1-22 to IV:1-25