Benign bone tumors DR: Gehan mohamed

Benign bone tumors Osteoma osteoid osteoma giant osteoid osteoma (osteoblastoma) osteochondroma

Definition of osteoma: A benign tumor composed of bony tissue, often developing from the skull.

Osteoma in the frontal sinus

Osteoma :formed of bone

osteoma

Osteoid Osteoma An osteoid osteoma is a benign (non-cancerous), small tumor that usually grows in the long bones of a person. Cell of origin : osteoblast. Signs/Symptoms : Pain specially at night relieved by NSAID and eliminated by excision. Age: years Sex: M > F (2:1) Anatomic Distribution: It arises in the Metaphysis of bones Over 50% of cases in femur or tibia Nearly every location, most frequent in femur, tibia, humerus, bones of hands and feet, vertebrae and fibula

Osteoid osteoma :Central radiolucent nidus surrounded by thickened sclerotic bone

Osteoid osteoma :Central hemorrhagic nidus surrounded by dense rim of sclerotic bone

Histopathologic picture of osteoid osteoma: It is formed of : - osteoid which is the unmineralized, organic portion of the bone matrix that forms prior to the maturation of bone tissue. - irregular bone trabecula

Histologic features of osteoid osteoma: the nidus of an osteoid osteoma demonstrates irregular masses of eosinophilic osteoid matrix (white arrow) and intensely stained bone trabeculae (black arrow) rimmed by osteoblasts (arrowhead).

Osteoid osteoma: formed of woven bone trabecula and osteoid

Osteoid Osteoma Prognosis/Treatment: Surgical excision is treatment of choice Recurrence can occur with incomplete excision of the tumor.

Osteoblastoma (Giant Osteoid Osteoma) It is similar with osteoid osteoma in histology But osteoblastoma differ in : Anatomic Distribution: - Predilection for vertebral column than long bones so Tumors of the spine can cause scoliosis and neurological symptoms. The lesion may clinically present with myleopathic and/or radicular symptoms. - much larger size (more than 2 cm up to 11.0 cm)

Osteochondroma

Exostosis (Osteochondroma) Is a benign tumor. Also known as exostosis Children and teenagers most affected, Male >> female. Clinically appear as slowly growing masses, painful if press on nerve tissue Solitary or multiple Multiple Hereditary Exostosis  autosomal dominant disease with inactivation of both copies of EXT gene in growth plate chondrocytes

Osteochondroma Benign projection of bone with cartilaginous cap Occurs in epiphyseal plate and grows laterally Exhibits cortex and medullary portion Conversion to sarcoma rare (<1%) but higher in patients with hereditary syndrome. May convert to malignancy if cartilage cap becomes thicker and contains disorganized calcifications

Osteochondroma Develops in bones of endochondral origin and arises from the metaphysis near the growth plate of long tubular bones. Occasionally develops from bones of the pelvis, scapula and ribs. Ultrasound safe and inexpensive way to evaluate thickness of cartilaginous capsule MRI method of choice to evaluate thicknesss of cartilaginous cap to rule out malignant conversion

- Radiograph can demonstrate that cortex of osteochondroma blends with cortex of normal bone

Osteochondroma:it consists of : - Fibrocartilagenous cap on top -Newly made bone trabecula Forms inner portion Medullary cavity of osteochondroma and bone are continuous