Osteoid Osteoma

• Small, ovoid benign bony tumor
  • Osteoidand trabeculae of newly formed bone embedding in highly vascular connective tissue
  • Lesion is rarely greater than 1 cm
  • Reactive perifocal bone sclerosis of several centimeters surrounds lesion
  • May have tenderness on palpation and atrophy of the involved limb side

Who gets it?

• 90% in first two decades of life (5-20 years-old)
• Males > Females

Presentation

• Unremitting, gradually increasing bone pain, deep pain, more pronounced at night
• unilateral, usually occurs in proximal femur or tibia or in vertebra; Described in all other bones except calvarium
• Spinal lesions may cause scoliosis; Reactive or painful scoliosis; Lesions near joints may cause effusions
• pain relieved by NSAIDS

Imaging

1. X-Ray(AP/Lateral)
   1. May have pain long beforeradiographicalevidence of lesion
   2. Osteosclerosis around a radiolucent nidus
2. 25% of osteoid osteomas are not visualized on X-ray, but can be seen on CT
3. Bone scan shows increased uptake

Treatment

• pain relieved by NSAIDS
• Some lesions spontaneously resolve after skeletal maturity
• Symptomatic relief
• Excision if excessive pain affecting function or quality of life

Osteoblastoma / Giant Cell Osteoid Osteoma

• Locally destructive, progressively growing lesion of bone
• Same characteristics as osteoid osteoma, but more destructive
• Predilection for vertebrate
• Size > 1 cm

CHLA Board Review 2005