Primarily the management of GCTs has been curettage followed
Primarily, the management of GCTs has been curettage followed by filling with bone cement [7,19]. However this has been associated with high recurrence rates. Additional treatment with adjuvants is often employed to reduce this recurrence. These adjuvants may include zinc chloride, bisphosphonates, phenol, liquid nitrogen and alcohol. [20–23]. Aggressive tumours may also be treated with wider excision and the use of surgical prostheses .
A recent development in treatment has been the use of the chemotherapy drug, denosumab, a monoclonal antibody which inhibits the osteoclastic activity of GCT . This is useful when the location of the tumour makes surgery difficult, for example in the sacrum or pelvis . Interim results of a phase II trial have shown that the drug may be used to reduce the need for more extensive surgery in difficult to resect tumours .
Osteoblastoma Osteoblastoma is a rare, benign bone tumour accounting for 14% of bone tumours . It most commonly affects people within the first four decades of life with a larger probability of it occurring in the second and third decades . Although any bone can be involved, osteoblastoma arises predominantly in the melanocortin 1 receptor with spinal lesions constituting one-third of reported cases . On CT imaging, osteoblastoma appearance is changeable and can often look like other tumours, including malignant ones. They can be distinguished due to their significantly large nidus size (>2cm in diameter, sometimes up to 15cm) compared to osteoid osteoma , but diagnosis needs to be confirmed on biopsy. Their nidus is formed by dense sclerotic woven bone and tumour trabeculae frequently connect with the surrounding bone. Osteoblastoma tends to remain confined to bone and does not normally penetrate the cortex, it has therefore usually a good prognosis and a low recurrence rate of around 15–20% . The first line of treatment is medical , if proven unsuccessful radiotherapy and chemotherapy might be attempted before choosing surgical interventions. There have only been a few cases reported where osteoblastoma has progressed to an osteosarcoma .
Osteoma Osteomas are a benign outgrowth of membranous bones, most commonly found in the para-nasal sinuses, skull and long bones . These benign tumours can grow on bone (homoplastic) and can present on other tissues (heteroplastic or eteroplastic) . They consist of osseous tissue that comprises of condensed bone with a well-defined border, without surface irregularities or satellite lesions. Without symptoms they are difficult to diagnose. Because of their increased incidence in divers and swimmers an inflammatory response has been thought to be one of the underlying mechanisms . Solitary osteoma are usually harmless, however if multiple are found they are a risk that the patient may have other underlying conditions, such as Gardner׳s syndrome . Although rare, surgical removal is indicated in these circumstances as well as in symptomatic patients.
Osteoid osteoma Rarely exceeding 1.5cm, osteoid osteoma is a benign bone tumour composed of osteoid and woven bone. Osteoid osteoma makes up 12% of all skeletal neoplasms, making it quite common. 50% of osteoid osteoma lesions are found in the fibia or tibia. The cortex of long bones is the most common location of the lesion. Dense, fusiform, reactive sclerosis characterise osteoid osteoma . It is more commonly found in young males under the age of 40 , whilst infants are rarely affected. The most common symptom is pain. The axial skeleton is affected much less, with skull and facial bones rarely affected. MRI, CT scanning and Isotopic scanning may be used for diagnoses and for the identification of central calcifications surrounded by the nidus (ovoid translucency) . In a study done by Assoun et al. 19 patients were examined using CT and MRI, results showed that CT was more accurate than MR imaging in detection of the osteoid osteoma nidus in 63% of cases .