The etiology of osteoid osteoma is unclear, but nerve fibers found within the nidus or the fibrovascular zone may explain the intensity of pain associated with these lesions.7-9 Infective or neoplastic lesions must be considered when increasing back pain is encountered in adolescents with progressive scoliosis.

The most common location for osteoid osteomas are within the diaphyseal or metaphyseal regions of the long bones, most commonly the femur but also frequently the tibia, vertebral arch, and fingers, Only 0.23% to 2% of osteoid osteomas occur in the ribs, which can be the cause of painful scoliosis if the rib head or neck is involved.10 This can cause scoliosis in a patient who would otherwise never develop it, which could be the case with Ms D. On plain radiographs these lesions appear as small, round, sclerotic foci within the cortical regions of the diaphysis or metaphysis. In the central region of the lesion there is a nidus or lucent area that usually measures <1 cm in diameter. Many times there will be a zone of periosteal reaction around the lesion that may obscure the nidus. On rare occasions, these lesions are found intra-articularly, subperiosteally, or intramedullary.


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Other imaging studies are often employed to aid in the diagnosis. Bone scans usually show increased and intense focal uptake of the tracer, typifying acute inflammatory reaction. A “double density sign” demonstrates focal activity of the nidus and surrounding area of less intense sclerosis. CT scans are best at identifying the nidus. MRI is rarely used to identify these lesions. Such scans will demonstrate soft-tissue edema but may fail to demonstrate the nidus.

Pathologically, the osteoid osteoma appears similar to osteoblastoma but is smaller in size. Osteoid osteoma is associated with a characteristic microscopic appearance of the nidus composed of a highly vascular stroma and seams of osteoid and immature trabeculae. The trabeculae are surrounded by plump osteoblasts. There is a sharp 1- to 2-mm fibrovascular rim that demarcates the rim of the nidus.

4. Treatment

The treatment of osteoid osteoma has historically been excision. Ponseti stated in 1947 that treatment “must be by an extensive block resection of the lesion, including a large portion of the surrounding sclerotic bone. The tumor and the symptoms have recurred in those patients whose lesions were treated by curettage or incomplete excision.”11 This form of treatment has provided excellent pain relief for the few reported cases of osteoid osteoma of the ribs in the literature. However, patient morbidity, recovery time, and cost-effectiveness must be evaluated when considering surgical excision of these lesions. It has been suggested that radiofrequency ablation and laser ablation are as effective as en bloc excision yet are associated with much less morbidity, shorter recovery time, and lower overall costs.12 These modalities have had success rates of 75% to 100%13-20 and 60% to100%,12, 21-23 respectively.

The take-home message from this case is that if an adolescent or young adult has unrelenting pain that is worse at night and partially or fully relieved by NSAIDs, osteoid osteoma should be high on the list of differential diagnoses to reduce the time to diagnosis and treatment.

Dr. Demill is in his fourth year of orthopedic surgery residency at the Ohio University’s Doctors Hospital in Columbus. Ms. Horn is the director of the orthopedic midlevel providers at Riverside Methodist Hospital in Columbus. Dr. Klamar is a faculty member at Nationwide Children’s Hospital and an assistant clinical professor at The Ohio State University, both in Columbus.

References

1. Jaffe, HL. “Osteoid-osteoma.” A benign osteoblastic tumor composed of osteoid and atypical bone. Arch Surg. 1935;31:709-728.

2. Georgoulis AD, Papageorgiou CD, Moebius UG, et al. The diagnostic dilemma created by osteoid osteoma that presents as knee pain. Arthroscopy. 2002;18:32-37.

3. Katz D, Thomazeau H. Osteoid osteoma of the proximal humerus: two misleading cases. J Shoulder Elbow Surg. 1997;6:559-563.

4. Miller SL, Hazrati Y, Klein MJ, et al. Intraarticular osteoid osteoma of the proximal humerus: a case report. J Shoulder Elbow Surg. 2003;12:94-96.

5. Stoffelen D, Martens M, Renson L, Fabry G. Osteoid osteoma as a cause of knee pain: a review of 10 cases. Acta Orthop Belg. 1992;58:395-399.

6. Mungo DV, Zhang X, O’Keefe RJ, et al. COX-1 and COX-2 expression in osteoid osteomas. J Orthop Res. 2002;20:159-162.

7. Schulman L, Dorfman HD. Nerve fibers in osteoid osteoma. J Bone Joint Surg Am. 1970;52:1351-1356. 

8. Esquerdo J, Fernandez CF, Gomar F. Pain in osteoid osteoma: histological facts. Acta Orthop Scand. 1976;47:520-524.

9. Hasegawa T, Hirose T, Sakamoto R, et al. Mechanism of pain in osteoid osteomas: an immunohistochemical study. Histopathology. 1993;22:487-491.

10. Kricun ME. Tumours of the ribs. In: Kricun ME, ed. Imaging of Bone Tumours. 1st ed. Philadelphia, PA: W.B. Saunders; 1993:304-328.

11. Ponseti I, Chester BK. Osteoid osteoma. J Bone Joint Surg Am. 1947;29:767-776.

12. Gebauer B., Tunn P-U, Gaffke G, et al. Osteoid Osteoma: Experience with laser- and radiofrequency-induced ablation. Cardiovasc Intervent Radiol. 2006;29:210-215.

13. de Berg JC, Pattynama PMT, Obermann WR, et al. Percutaneous computed-tomography-guided thermocoagulation for osteoid osteomas. Lancet. 1995;346:350-351.

14. Lindner NJ, Ozaki T, Roedl R, et al. Percutaneous radiofrequency ablation in osteoid osteoma. J Bone Joint Surg Br. 2001;83-B:391-396.

15. Cioni R, Armillotta N, Bargellini I, et al. CT-guided radiofrequency ablation of osteoid osteoma: long-term results. Eur Radiol. 2004;14:1203-1208.

16. Soong M, Jupiter J, Rosenthal D. Radiofrequency ablation of osteoid osteoma in the upper extremity. J Hand Surg Am. 2006;31:279-283.

17. Woertler K, Vestring T, Boettner F, et al. Osteoid osteoma: CT-guided percutaneous radiofrequency ablation and follow-up in 47 patients. J Vasc Interv Radiol. 2001;12:717-722.

18. Vanderschueren GM, Taminiau AH, Obermann WR, Bloem JL. Osteoid osteoma: clinical results with thermocoagulation. Radiology. 2002;224:82-86.

19. Akhlaghpoor S, Tomasian A, Arjmand Shabestari A, et al. Percutaneous osteoid osteoma treatment with combination of radiofrequency and alcohol ablation. Clin Radiol. 2007;62:268-273.

20. Hadjipavlou, AG, Tzermiadianos MN, Kakavelakis KN, Lander P. Percutaneous core excision and radiofrequency thermo-coagulation for the ablation of osteoid osteoma of the spine. Eur Spine J. 2009;18:345-351. 

21. Gangi A, Alizadeh H, Wong L, et al. Osteoid osteoma: percutaneous laser ablation and follow-up in 114 patients. Radiology. 2007;242:293-301. 

22. Sequeiros RB, Hyvönen P, Sequeiros AB, et al. MR imaging-guided laser ablation of osteoid osteomas with use of optical instrument guidance at 0.23 T. Eur Radiol. 2003;13:2309-2314.

23. Witt JD, Hall-Craggs MA, Ripley P, et al. Interstitial laser photocoagulation for the treatment of osteoid osteoma: results of a prospective study. J Bone Joint Surg Br. 2000;82-B:1125-1128.

All electronic documents accessed December 15, 2010.