Osteoid osteoma of the sesamoid bone: An unusual localization.

Osteoid osteoma is the most common benign bone tumor because it accounts for 10-12% of all these tumors. Localized most often with long bones (75% of cases), especially in the tibia and femur, osteoid osteoma can evoke other etiologies, especially when it is juxta-articular. We report the case of an osteoid osteoma of the sesamoid in a 23-year-old patient with no particular history who presented pain at the root of his hallux evolving for 6 months. The clinical examination was without abnormalities. Standard X-rays found no lesions. The tomodensitometry of the foot showed an image "cockade" with a peripheral sclera ring. The patient underwent surgical excision with simple operative follow-up and disappearance of pain at one year of follow-up. The histopathological study confirmed the diagnosis. The osteoid osteoma of the sesamoid bone is exceptional. The diagnosis may be delayed due to misleading "articular" symptomatology.