Table of Contents
Definition / general | Terminology | Sites | Clinical features | Diagnosis | Radiology description | Radiology images | Prognostic factors | Case reports | Treatment | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Cytology description | Cytology images | Electron microscopy description | Differential diagnosis | Additional referencesCite this page: Lucas DR. Osteoblastoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/boneosteoblastoma.html. Accessed January 16th, 2021.
Definition / general
- Benign, bone forming tumor comprised of anastomosing trabeculae of osteoid and woven bone rimmed by osteoblasts
- Rare; 1% of primary bone tumors
Terminology
- Also called giant osteoid osteoma
Sites
- Wide skeletal distribution
- 1 / 3 spine and sacrum
Clinical features
- Progressive pain, not as intense as with osteoid osteoma
- Spinal tumors have neurological findings and scoliosis
- Rarely presents with fever, weight loss, generalized periostitis (“toxic osteoblastoma”, Am J Surg Pathol 1979;3:463)
Diagnosis
- Radiographic correlation often helpful
Radiology description
- Demarcated bone tumor with intralesional ossification
- Mostly nondestructive growth
- Some have central nidus or nidi
- Tumors with secondary ABC changes (aneurysmal bone cyst) are expansile
- Spinal tumors originate in dorsal elements, may secondarily involve vertebral body
- Up to 25% of radiographs are suspicious for malignancy (AJR Am J Roentgenol 1976;126:321)
Radiology images
Contributed by Dr. David R. Lucas
Images hosted on other servers:
Prognostic factors
- 20% local recurrence
- Tumor localized near central neural axis have greater morbility and mortality
Case reports
- 11 year old girl with skull base osteoblastoma (Skull Base 2009;19:437)
- 13 year old boy with spinal osteoblastoma (Arch Pathol Lab Med 2010;134:1460)
Treatment
- Curettage, en bloc resection
Gross description
- Mostly curetted gritty, red fragments of osteoblastoma
- Intact tumors well demarcated with scalloped edges
- Often hemorrhagic
- One or more nidi
Gross images
Microscopic (histologic) description
- Anastomosing trabeculae of osteoid and woven bone
- Rimmed by single layer of benign activated osteoblasts
- Numerous osteoclasts
- Loose fibrovascular stroma between bone trabeculae
- Intralesional hemorrhage and secondary ABC common
- Does not permeate adjacent host trabecular bone
- Often pagetoid reversal lines
- Central nidus of dense woven bone in some
- Low mitotic rate
- Rare tumors with cartilaginous matrix
- Rare tumors with degenerative atypia (pseudomalignant osteoblastoma)
Microscopic (histologic) images
Contributed by Dr. David R. Lucas
Images hosted on other servers:
Cytology description
- Large osteoblasts with eccentric cytoplasm and perinuclear hof and large vesicular nuclei with prominent nucleoli
- Osteoclastic giant cells
- Osteoid matrix
Cytology images
Electron microscopy description
- Children and young adults
- Mean age 20 years, wide age range (6 - 75 years)
- 60% female (2:3 male:female ratio)
Differential diagnosis
- Aggressive osteoblastoma
- Aneurysmal bone cyst
- Giant cell tumor
- Osteoblastoma-like osteosarcoma
- Osteoid osteoma
- Osteoma with osteoblastoma like features (Arch Pathol Lab Med 2009;133:1587)
Additional references