Answer for BIR CoW 31 Aug 2025
Osteoid osteoma of tibia
Findings
Eccenteric intramedullary ovoid lucency and marked surrounding sclerosis and cortical thickening in the lateral aspect of the proximal meta-diaphysis of right tibia
Discussion
Osteoid osteomas are benign bone-forming tumor that typically occur in children (particularly adolescents). Clinical Features: • There is a 2:1 male predominance; 10- to 25-year age range is most common. • Severe pain, worse at night, that is dramatically alleviated by the use of aspirin occurs in 65% of cases. • Muscle atrophy and limp occur in long-standing lesions of the lower extremities. • Painful and rigid scoliosis, with the lesion on the concave side of the curve, usually occurs in the lumbar spine. • 50% occur in the femur and tibia; 10% occur within the spine, usually in the neural arch. Pathologic Features: • The tumor consists of a nidus, that is usually ≤1 cm in diameter. • Target calcification may occur in the center of the radiolu cent nidus. • The most common location within the bone is in the cortex, with intramedullary and subperiosteal lesions also occurring. Radiologic Features : • The characteristic appearance of a cortical lesion is as a radiolucent nidus surrounded by florid perifocal reactive sclerosis. • Often, CT and bone scans are necessary to demonstrate the nidus, especially in the spine. • Intramedullary lesions that are intracapsular (such as the femoral neck) provoke much less reactive sclerosis. • 60% of the spinal lesions are in the lumbar spine, usually creating an ivory pedicle or neural arch. Differential Diagnosis : • Brodie’s abscess is the prime clinical and radiographic dis ease entity to mimic osteoid osteoma. This differentiation cannot be made clinically because patients with either present with a similar history. Radiographic differentiation is suggested by observing the nidus, usually > 2 cm in Brodie’s abscess. Treatment and Prognosis : • In surgically accessible lesions a wide en bloc excision is the treatment of choice. • It is not necessary to remove the reactive sclerosis, even though this may form the major part of the radiologic presentation. • Vertebral body lesions are often treated with irradiation. • Prognosis is good, with little chance of recurrence when complete surgical excision of the nidus is accomplished
REFERENCE
Yochum and Rowe ‘s Essentials of Skeletal Radiology Gaillard F, Walizai T, Niknejad M, et al. Osteoid osteoma. Reference article, Radiopaedia.org (Accessed on 17 Aug 2025) https://doi.org/10.53347/rID-1802
Findings
Eccenteric intramedullary ovoid lucency and marked surrounding sclerosis and cortical thickening in the lateral aspect of the proximal meta-diaphysis of right tibia
Discussion
Osteoid osteomas are benign bone-forming tumor that typically occur in children (particularly adolescents). Clinical Features: • There is a 2:1 male predominance; 10- to 25-year age range is most common. • Severe pain, worse at night, that is dramatically alleviated by the use of aspirin occurs in 65% of cases. • Muscle atrophy and limp occur in long-standing lesions of the lower extremities. • Painful and rigid scoliosis, with the lesion on the concave side of the curve, usually occurs in the lumbar spine. • 50% occur in the femur and tibia; 10% occur within the spine, usually in the neural arch. Pathologic Features: • The tumor consists of a nidus, that is usually ≤1 cm in diameter. • Target calcification may occur in the center of the radiolu cent nidus. • The most common location within the bone is in the cortex, with intramedullary and subperiosteal lesions also occurring. Radiologic Features : • The characteristic appearance of a cortical lesion is as a radiolucent nidus surrounded by florid perifocal reactive sclerosis. • Often, CT and bone scans are necessary to demonstrate the nidus, especially in the spine. • Intramedullary lesions that are intracapsular (such as the femoral neck) provoke much less reactive sclerosis. • 60% of the spinal lesions are in the lumbar spine, usually creating an ivory pedicle or neural arch. Differential Diagnosis : • Brodie’s abscess is the prime clinical and radiographic dis ease entity to mimic osteoid osteoma. This differentiation cannot be made clinically because patients with either present with a similar history. Radiographic differentiation is suggested by observing the nidus, usually > 2 cm in Brodie’s abscess. Treatment and Prognosis : • In surgically accessible lesions a wide en bloc excision is the treatment of choice. • It is not necessary to remove the reactive sclerosis, even though this may form the major part of the radiologic presentation. • Vertebral body lesions are often treated with irradiation. • Prognosis is good, with little chance of recurrence when complete surgical excision of the nidus is accomplished
REFERENCE
Yochum and Rowe ‘s Essentials of Skeletal Radiology Gaillard F, Walizai T, Niknejad M, et al. Osteoid osteoma. Reference article, Radiopaedia.org (Accessed on 17 Aug 2025) https://doi.org/10.53347/rID-1802
Note:
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!
We do not discourage differential diagnosis. But all the differentials must satisfy the findings noted in the case.
If you feel you have answered rightly but cannot find your name in the above list, please call 09551942599.
Did you Know?
The order in which the names appear in this winner's list is based on the time of submission. The first person to send the correct answer gets his/her name on top of the list!