**2. Clinical presentation**

Osteosarcomas most commonly occur in the metaphysis of long bones, for the most part around the knee in the distal femur (43%0 or proximal tibia (23%), followed in frequency by the humerus (10%) (**Figure 1**) [10]. One in ten patients has a tumor of axial location, most commonly in the pelvis. Tumors of axial location tend to have a worse prognosis with higher recurrence rates and more advanced stages at presentation [10–12]. Patients complaint about intermittent pain and swelling, the pain is known to be severe enough to awake the patient during sleep hours [13]. Pain of a high intensity can potentially be an indication of an impending pathological fracture, fact that occurs in up to 10% of these patients [14]. A pathological fracture may represent a more aggressive tumor and the microRNA profile of tumors that fractured have been shown to be different that those without a break. Additionally, tumors that presented with a fracture were associated with a higher risk of metastatic spread as well as a worse prognosis overall [14].

About 20% of osteosarcoma patients have metastatic disease at presentation. Most of those secondary lesions are in the lung, bone being the second most common spread location [10]. Tumor size has been implicated as a risk factor for lung spread [15]. When osteogenic sarcoma presents in older population, there is a more frequent axial location compared to younger patients, being almost 40% of the elderly patients versus 10% in children and teenagers [16]. Additionally, the older patients tend to have larger tumors, more frequency of metastatic disease at presentation and a worse general prognosis with less opportunity for limb salvage procedures and inability to receive the full systemic treatment protocol as compared to younger patients [17]. Moreover, when the chemotherapy response seems to

**Figure 1.** *Fifteen-year-old patient with a left proximal tibia osteosarcoma, presented with local pain and swelling.*

**75**

**Figure 2.**

*Osteosarcoma*

drops to 8% [18].

**3. Staging**

*DOI: http://dx.doi.org/10.5772/intechopen.96765*

triangle or a sunburnt pattern (**Figure 2**) [21].

the affected bone must be obtained for tumor re-assessment.

be poorer in these patients with a lower percentage of necrosis noted on the postchemotherapy tumor resection piece [10]. The 5-year overall survival is 50% for the elderly when surgical treatment is feasible, when surgery is not an option that rate

The assessment of osteosarcoma patients usually begins with orthogonal plain radiographs of the site of pain or mass. Plain films usually reveal an aggressive appearing lesion that prompts more advanced imaging studies such as a CT scan or ideally an MRI with and without contrast of the entire affected bone. On radiographic imaging the lesions may be more blastic, lytic or mixed pattern depending on the osteosarcoma subtype. In more advanced cases, there will be cortical permeation and an associated soft tissue component, although this is a more common finding in Ewing's sarcomas [19]. For purely lytic lesions, radiographic evidence is only present when a substantial percentage of the bone has been affected (30–50%), thus the recommendation in cases of persistent symptoms is to proceed with an MRI even with a negative plain film [20]. Additional findings on radiographs include a wide area of transition, cortical destruction and a periosteal reaction such as Codman's

The next imaging study should be a full bone length MRI with and without contrast of the affected area, this will serve diagnostic and staging purposes as well, since it has the ability of detecting skip lesions. MRI studies provide information regarding the complete extent of the tumor within the bone, and its closeness to surrounding structures such as vessels and nerves. Additionally, it provides information regarding joint invasion, and, extremely important in the pediatric population, physis involvement by the tumor [22]. This information will dictate the proposed surgical intervention (**Figure 3**). After neoadjuvant chemotherapy and prior to the definitive surgical treatment a new MRI with and without contrast of

Following the initial images, usually proceeds a close or open biopsy of the lesion for pathology confirmation of the diagnosis and grading of the tumor. It is

*Radiographic images of a patient with a distal femur conventional, central, osteoblastic, high grade* 

*osteosarcoma. The tumor presents a mixed, blastic and lytic, moth-eaten pattern.*

be poorer in these patients with a lower percentage of necrosis noted on the postchemotherapy tumor resection piece [10]. The 5-year overall survival is 50% for the elderly when surgical treatment is feasible, when surgery is not an option that rate drops to 8% [18].
