Curriculum · Musculoskeletal / Orthopedic / Rheumatology
Osteoblastoma
What it is
Osteoblastoma is a bone tumour that comes from the osteoblast, and it sits in the benign group beside osteoma and osteoid osteoma, while osteosarcoma is the malignant tumour of the same origin. One page gives its site as the diaphysis at an age of 10 to 30; another gives it at 20-40 yrs, in the axial skeleton, in the metaphysis and diaphysis. It is larger and more aggressive than osteoid osteoma but has the same histological features, and its characteristic feature is a nidus that secretes prostaglandin. A third page groups it with the giant cell tumour and the aneurysmal bone cyst as the benign aggressive bone tumours, which affect patients of skeletal maturity with a peak in the 3rd decade, and gives its sites as the distal femur, proximal tibia, distal radius, sacrum, tarsal bones and spine.
How it presents
The typical point in the story is bone pain that is not relieved by NSAIDS. Painful scoliosis is the other presentation named, and there too the pain is not relieved by analgesia - which is the line that separates it from osteoid osteoma, whose night pain is relieved by analgesia. Where it is grouped with the giant cell tumour and the aneurysmal bone cyst, the symptoms given are local tenderness and swelling, with or without symptoms of nerve root compression, and that last one is named for osteoblastoma alone.