Osteoid osteoma is a benign tumor of the skeletal system which primarily targets younger individuals, and most commonly develops in long bones. Clinical presentation involves intense localized pain, which is often not relieved by analgesics. Diagnosis can be made by imaging studies such as CT scanning, and permanent effective treatment can be achieved through percutaneous surgical techniques.
The classical clinical presentation of patients with osteoid osteoma involves the presence of localized pain (at the site of the tumor), and it is described as continuous, deep, and intense . Depending on the localization of the tumor, patients may report pain in their arms , legs, feet, or hands in rare cases. In the majority of patients, pain is intensified during night time, and can sometimes wake the patient up, while other symptoms, such as restricted range of motion or local swelling may be observed. This tumor can present as arthritis in cases of phalangeal or wrist involvement , as well as macrodactyly and clubbing  . In rare cases, if the tumor is located near the growth plate, limb overgrowth and discrepancy may be observed in young children. Sometimes the pain is considered to be of different origin, especially since this tumor occurs in teenagers and young adults, in whom pain can be prescribed to growth or some form of trauma, which can delay the diagnosis for weeks, and possibly years.
Physical examination will highly likely reveal the location of the tumor, and atrophy of surrounding muscles may be observed in patients who are experiencing severe pain, which can cause muscle misuse.
Clinical examination, as well as patient history, should point to a localized issue of the musculoskeletal system, and in all cases, imaging techniques are required to establish the diagnosis. Usually, a radiolucent area between 1-2 cm in diameter can be observed on plain X-ray, which can be surrounded by a halo ring that occurs as a result of bone sclerosis and cortical hypertrophy, which are hallmarks of osteoid osteoma. However, subperiosteal lesions may not be apparent, while both epiphyseal and metaphyseal lesions can show minimal or no sclerosing changes around the nidus, which is why CT scanning is recommended as the imaging technique of choice - to obtain a better view of the soft tissues, to exclude the presence of other types of tumors, and to serve as a guide to excision . CT is superior to MRI, while radionuclide bone scanning with technetium-99m can be performed, since osteoid osteoma causes an uptake of isotope activity .
The definite diagnosis is achieved through a biopsy, which can be performed percutaneously, although results can be obtained in only 50% of the cases when samples through percutaneous techniques are obtained. For these reasons, a combination of clinical symptoms, as well as radiographic findings, is the key in order to diagnose osteoid osteoma. It is important to distinguish this benign bone tumor from other potentially debilitating, or sometimes life-threatening bone and joint illnesses such as osteomyelitis, arthritis, stress fractures, or osteoblastoma, which is also a benign tumor, and has almost identical features as osteoid osteoma.
Treatment strategies include pain-relieving therapy and localized surgical techniques to remove the tumor.
NSAIDs are the drugs of choice for the management of pain caused by osteoid osteoma, such as aspirin, presumably through inhibition of prostaglandin synthesis. Contraindications for use of NSAIDs exist, such as peptic ulcer disease, and for most patients, the pain becomes too intense and chronic , in which case other forms of treatment are necessary. However, pain management with NSAIDs can significantly defer surgical treatment.
Surgical excision of the nidus is the treatment of choice for patients in whom NSAIDs are insufficient. Localized percutaneous techniques provide immediate relief, and are curative in the vast majority of cases, with very low rates of recurrence. Curettage and unroofing of the nidus encompasses the gradual removal of the overlying bone that is covering the central part of the tumor and its subsequent removal. This procedure is preferred for patients whose tumor is located in more complicated locations, such as the femoral neck, and can help maintain structural support for the area, without disrupting the underlying bone.
In the majority of cases, however, radiofrequency ablation is the treatment of choice, through heat production and use of energy current, and has a very high rate of success . Open surgery is reserved for patients in whom percutaneous techniques are not possible, for ex. if the tumor is in close proximity to other important structures (Such as the spinal canal, tumors that are located in hands, wrists, or feet), or because heat caused by ablation may damage the surrounding structures.
The prognosis of osteoid osteoma is good, since this tumor presents as a solitary lesion, has a relatively small diameter, and poses no metastatic potential. Treatment can be delayed, sometimes significantly, through the use of NSAIDs, but curative rates are very high with excision and localized percutaneous techniques, with the most effective one being radiofrequency ablation.
Osteoid osteoma is a benign bone-forming tumor that histologically appears as interlacing trabeculae of woven bone . It is still unknown what the cause of the tumor is, and why are young adults in their second and third year most commonly affected.
This benign tumor comprises between 8-10% of all symptomatic benign bone tumors, and about 5% of all primary bone tumors. Osteoid osteoma is most commonly diagnosed in teens and young adults (between 10 and 30 years), but it can affect individuals of any age, while about 3% of cases occur in children younger than 5 years . It is established that male individuals are more commonly affected, with a 2-3:1 ratio, while a racial predilection of this tumor has not been observed.
Osteoid osteoma is a tumor that usually involves the cortex of the bone, and is characterized by a central area called the nidus, which can potentially become sclerotic and mineralized, while the surrounding structures include interlacing trabeculae of woven bone and osteoblasts, as well as vascular connective tissue.
The pathogenesis of this tumor is still not completely understood, and several theories have been proposed, such as an inflammatory process (intracellular viral particles were observed on electron microscopy). The pain that is present in patients with this tumor includes generation of prostaglandins (which can account for intensifying pain during night time because of increased activity of prostaglandins during the night) , bradykinin, as well as vasodilation and edema, all contributing to stimulation of intraosseous nerve endings .
Having in mind the fact that the cause of this tumor is unknown, there is little to be done in terms of prevention, but it is a relatively benign lesion that can be successfully managed, and poses no threat for the patient.
Initially described in the 1930s , osteoid osteoma is a benign bone tumor, usually between 1.5-2 cm in diameter, that is characterized by a radiolucent central area - the nidus, and surrounding sclerosing bone, as well as loose vascular, connective and adipose tissue. It most commonly develops in young adults, usually in their second and third decades of life, with a 2:1 predilection towards the male gender, for unknown reasons . It usually appears in the long bones, with the most common sites being the tibia and proximal femur , while other sites include the phalanges, bones of the foot, and the vertebrae. Clinical presentation almost universally involves the presence of intense localized pain that intensifies at night. The diagnosis is achieved through imaging techniques, such as plain radiography or computed tomography (CT), while magnetic resonance imaging (MRI) can also be used, while radionuclide scanning can be effective in distinguishing osteoid osteoma from other tumors of the skeletal system . This benign tumor does not metastasize, and is usually treated by percutaneous techniques, such as local excision, curettage, or radiofrequency ablation, while open surgery is rarely indicated. Non-steroidal anti-inflammatory drugs (NSAIDs) can be helpful in relieving pain, and surgical treatment may be replaced through the use of these medications, as the tumor does not pose a threat to the patient .
Osteoid osteoma is a small benign solitary tumor of the bones which occurs in individuals during their second and third decade of life, and is diagnosed more frequently in males. It is still not known why this tumor appears. It usually develops in the bones of the lower extremities, but it can appear on any bone in the body, including the arms, hands, feet, and the spine. Virtually all patients report severe localized pain at the site of the tumor, because the central part of the tumor - the nidus - produces intense pain. The majority of patients describe the pain as sharp, intense, and more often during the night, which may even wake up the patient. Limb asymmetry and unequal growth may be observed if the tumor is located inside the growth plate, while muscle atrophy can occur in patients who avoid using their extremity because of severe pain.
The diagnosis of osteoid osteoma is made based on findings made during the clinical examination, and imaging techniques. A plain X-ray may reveal the tumor, while computed tomography (CT scan) is the recommended imaging technique, because it can provide a good view of the bone and surrounding soft tissues. Once the diagnosis is made, treatment principles primarily include pain relieving, through the use of non-steroidal anti-inflammatory drugs, such as aspirin, which can defer other forms of therapy for a prolonged period of time. However, since the majority of patients cannot tolerate pain even with appropriate medication, certain types of minimally invasive surgical techniques are performed, usually under local anesthesia. Excision of the tumor can provide permanent relief, and rates of recurrences are minimal. This tumor is benign in origin, has no potential to become malignant and metastasize, and can be successfully treated.