Osteoid Osteoma

Question 1

Incidence

Answer 1

MC cause of painful scoliosis in adolescent pop

3:1 M:F ratio

Question 2

Location

Answer 2

-lower extremity (>50%); prox femur> tibia diaphysis
Usually in bone cortex
-Spine (10-15%) thoracic and lumbar > cervical and sacral (maj post elements)
-Hand (5-10%): scaphoid and prox phalanx
Foot (

Question 3

nidus

Answer 3

central nodule of woven bone and osteoid with osteoblastic rimming

Question 4

reactive zone

Answer 4

area of thickened bone and fibrovascular tissue

Question 5

Pain

Answer 5

local [PG] and [COX 1/2]

increased #/size of unmyelinated nerve fibers within the nidus

Question 6

Prognosis

Answer 6

• pain resolves after an avg of 3 yrs
• lesion spon resolves 5-7yrs
• Spine: early resection (w/n 18 months) leads to resolution of scoliosis in young children (

Question 7

tx

Answer 7

nsaids, radiofreq ablation, surgical resection