osteoblastom

Osteoblastom is a rare, benign bone tumor characterized by the proliferation of osteoblasts, the cells responsible for bone formation. It primarily affects adolescents and young adults, with a slight predilection for males. The tumor typically arises in the long bones, particularly around the knee (distal femur and proximal tibia), but can also occur in other skeletal locations.

Clinically, osteoblastomas often present with persistent, dull pain that may not respond well to nonsteroidal anti-inflammatory drugs (NSAIDs). The pain is usually localized and can be episodic or continuous. In some cases, patients may experience swelling or restricted movement depending on the tumor’s location.

Radiographically, osteoblastomas appear as expansile, radiolucent lesions with scattered mineralization. They tend to have well-defined margins but may display some degree of cortical expansion or thinning. On imaging studies, they can sometimes resemble osteoid osteomas; however, osteoblastomas are generally larger (>2 cm) and tend to have a more aggressive appearance.

Histologically, osteoblastomas are composed of osteoid and immature bone lined by active osteoblasts, set within a vascular stroma. The tumor architecture is less organized than that of osteoid osteoma, with more prominent cellularity.

Treatment typically involves surgical excision or curettage, often with safety margins to reduce recurrence risk. Although osteoblastomas are benign, they can sometimes recur locally if not adequately removed. Malignant transformation is exceedingly rare.

Prognosis after complete excision is generally excellent, with most patients experiencing resolution of symptoms and no further complications. Due to its rarity and variable presentation, accurate diagnosis often requires a combination of clinical, radiological, and histological assessments.