Osteoid osteoma of the rib: A report of an extremely rare condition.

Introduction: Osteoid osteoma (OO) is a type of benign bone tumor that usually affects long bones of the lower extremities. In this case report, we describe a successful surgical resection of an OO located in the rib which is an extremely rare location.

Case Presentation: This is a 23-year-old man, referred to our thoracic surgery department for a very intense nocturnal right chest pain for over two months, the physical examination was normal without clinically palpable chest mass. The CT scan showed an osteocondensing lesion at the junction of the middle and posterior arches of the right 6th rib suggesting Ewing's sarcoma, a PET CT was then requested showed an appearance of a regular non-hypermetabolic inhomogeneous condensation at the junction of the middle and posterior arcs of the 6th right rib. After multidisciplinary concertation, a CT-guided biopsy of the lesion was performed, the histological examination of which revealed an osteoid osteoma, then a complete resection of the lesion was performed under posterolateral thoracotomy which histology confirmed a costal osteoid osteoma. The patient is currently in good health condition with complete disappearance of chest pain after one month of the operation and does not present any complications for the long-term follow-up.

Discussion: Osteoid osteoma (OO) is a benign primary bone tumor with unknown pathogenesis. That occurs in patients during the first two decades of life in about 60 to 75% of cases with a strong predilection for long bones, in 60 to 70% of cases. Flat bones, such as the skull, jawbones, innominate bones, and ribs are rarely described (McDermott et al., 1996 [1]). The standard treatment for OO is complete surgical excision, which is offered to the patient when the pain is chronic and not relieved by medical treatment (Osteoid osteoma: the results of surgical treatment [Internet] [2]).

Conclusion: The osteoid osteoma of the rib is a very rare entity of bone neoplasms, this is the first case in our department that demonstrates that the OO of the rib must be suspected affront any painful rib and that complete surgical excision when it's possible, is a safe and effective treatment.