Osteoblastoma

Osteoblastoma is benign primary bone tumour. It is grouped with the chondro-osseous tumours.

Osteoblastoma
Diagnosis in short
Osteoblastoma. H&E stain.
LM	anastomosing bony trabeculae with variable mineralization, osteoblastic rimming, no nuclear atypia of osteocytes
LM DDx	osteoid osteoma, osteosarcoma
Site	bone - vertebral column typically, other bones
Clinical history	usu. 15-20 years old, males > females
Symptoms	usu. pain
Radiology	often >=2.0 cm (similar lesions 1-2 cm may be osteoid osteoma), often well-circumscribed, +/-cortical expansion, +/-cortical destruction
Prognosis	benign, may be locally destructive
Clin. DDx	osteosarcoma

General

• Benign bone tumour - that can be locally destructive and occasionally recurs.
• Uncommon.
• Typically age 15-20 and male (male:female = ~2:1).
  • Very large age range.
• Treatment: resection.

Gross

• Bone.
  • Vertebral column and sacrum - most common in one large series.
• Size important as per WHO definition: ‡
  • >= 2.0 cm: osteoblastoma.
  • <=1.0 cm: osteoid osteoma.
  • >1 cm and <2 cm: clinical and radiologic criteria should be considered.

Note:

• ‡1.5 cm is a diagnostic size cutoff seen in older references.

Radiology

Features:

• Often well-circumscribed, +/-cortical expansion, +/-cortical destruction.

Note:

• May be described as malignant by radiology.

Microscopic

Features:

• Anastomosing bony trabeculae with:
  • Osteoblastic rimming.
    • Cells line-up at edge of bone.

Notes:

• Histomorphologically near identical/indistinguishable from osteoid osteoma.

DDx:

• Osteosarcoma.

Images

• 

  Osteoblastoma - high mag. (WC)

• 

  Osteoblastoma - low mag. (WC)

• 

  Osteoblastoma - low power. (SKB)

• 

  Osteoblastoma - medium power. (SKB)

• 

  Osteoblastoma - medium power. (SKB)

• 

  Osteoblastoma - Higher power - Osteoblastic rimming. (SKB)

Sign out

BONE, LEFT FEMUR, EXCISION:
- OSTEOBLASTOMA.

See also

• Chondro-osseous tumours.
• Bone.