9200/0 Osteoblastoma, NOS


Giant osteoid osteoma


ICD-O-3 topography code: C40-C41

Osteoblastoma is a rare, benign bone-forming neoplasm characterized by the production of woven bone spicules and bordered by prominent osteoblasts. It most commonly affects spine and sacrum. The vast majority of cases are intra-osseous (medullary), with a sharp border between tumour and medullary cavity. Osteoblastomas are well-circumscribed, lytic tumours almost always confined by a periosteal shell of reactive bone. They have an extremely rich vascular supply; extravagated red blood cells are common. Tumour size ranges from 2 to >15 cm. The histological characteristics of osteoblastoma are similar to those of osteoid osteoma. In contrast to osteosarcoma,osteoblastomas do not infiltrate and isolate pre-existing lamellar bone structures.

Osteoblastoma preferentially affects male teenagers and young adults. Treatment of choice is surgical curettage; large lesions may have to be excised. The prognosis is excellent and recurrence unusual 1
Fletcher CDM, Unni KK, Mertens F (Eds.)
World Health Organization Classification of Tumours. Pathology and Genetics of Tumours of Soft Tissue and Bone.
3rd Edition
IARC Press: Lyon 2002


Nasal cavity and Sinuses
ICD-O-3 topography code: C30-C31

A rare benign bone-forming neoplasm usually arising from the spine. It is a well-circumscribed lytic tumor that varies in size. The tumor is composed of woven bone trabeculae and shares similar histologic characteristics with the osteoid osteoma. Surgical curettage is the treatment of choice. The prognosis is excellent.