Osteoblastoma

Radiological appearances:

A)Radio graphs: 

1-Lucent lesion containing matrix calcification surrounded by bone reaction may have expanded giving aneurysmal appearance.

2-Commenest site is posterior element of vertebra.

3-Differential diagnosis:

-Osteoid osteoma: Can be differentiated only by size, osteoid osteoma is less than 2 cm while osteoblastoma is bigger than that size.

-Aneurysmal bone cyst, esinophilic granuloma, giant cell tumor and osteogenic sarcoma.

Osteoblastoma of the sacrum in a 37-year-old man with sacral pain. CT scan shows a hypo attenuating area with central calcifications and minimal surrounding sclerosis.

CT scan shows a destructive expansile lesion with osteoid matrix extending into the spinal canal.