Localization

The most frequent localizations of Ewing’s sarcoma are in the long tubular bones, here mainly in the tibia and fibula, or in flat bones. Nevertheless, as a malignant bone cancer, Ewing’s sarcoma can affect all bones. The larger bones are most frequently affected, the smaller ones rather rarely.

If the long tubular bones are affected, the tumor is usually found in the area of the so-called diaphysis, the shaft area. Preferred localizations: Due to the early strong hematogenic metastasis (see following section), localization in the soft tissues is also conceivable.

Approx.
30% femur (thigh bone)
Approx. 12% Tibia (shin bone)
Approx. 10% humerus (upper arm bone)
Approx.
9% basin
Approx. 8% fibula (fibula).

Ewing’s sarcoma is only localized in approximately one in five cases in the pelvic bone as the primary tumor (the tumor’s point of origin). Significantly more often, however, the primary tumor is located in a long tubular bone.

The first symptoms can be swelling, pain and overheating in the area of the pelvis. The foot is a rare localization of a primary tumor. It is more common that primary tumors from the tibia or fibula promote a metastasis in the foot.

If an unclear, painful swelling and overheating of the foot occurs, especially in adolescence, Ewing’s sarcoma should be ruled out in addition to juvenile arthritis. This does not necessarily mean that the worst is to be expected. Targeted diagnostics in the form of imaging can provide initial clarity about the causes of the complaints.

Metastasis

As already mentioned above, Ewing’s sarcoma is considered to have metastasized at an early stage of hematogenesis (= via the bloodstream). Metastases can therefore also settle in soft tissue. The lung is primarily affected.

However, the skeleton can also be affected by metastases via the bloodstream.The fact that Ewing’s sarcoma can be classified as early metastatic is proven by studies which show that metastases can be detected in about 25% of all cases at the time of diagnosis. Since metastases unfortunately cannot always be detected, the dark rate is probably much higher. Ewing – Sarcomas can cause various symptoms.

They will be listed below: A tumor exclusion is possible with sufficient probability if the following criteria are met after clinical, imaging and laboratory diagnostics: The visible swelling, the proven mass or unclear symptoms can be clearly explained and proven by a non-tumorous disease.

Pain of unclear cause
Swelling and usually also pain in the area(s) affected
Lymph node swelling
Local signs of inflammation (redness, swelling, overheating)
Unintentional weight loss
Functional limitations up to paralysis
Fracture without accident event
Night sweat
Moderate leukocytosis (= increase of the leukocyte count in the blood)
Reduced performance
No spatial requirement is detectable or

Basic diagnostics: In principle, imaging techniques are used for basic diagnostics. These are X-ray examination X-ray examination in the area of the tumor localization (at least 2 levels) Sonography Sonography of the tumor (especially in the case of differential diagnostic suspicion of soft tissue tumor) In order to obtain additional information and to enable differential diagnostic delimitations, laboratory diagnostics (examination of laboratory values) is used.

The following values are determined within the scope of this laboratory diagnostics:

Blood count
Iron (because lowered in tumors)
Electrolytes (to rule out hypercalcemia)
BSG (blood sedimentation rate)
CRP (C-reactive protein)
Alkaline phosphatase (aP)
Bone-specific (aP)
Acid phosphatase (sP)
Prostate Specific Antigen (PSA)
Uric acid (HRS): increased during high cell turnover, e.g. in hemoblastosis
Total protein: in consuming processes protein electrophoresis decreases
Urine status: paraproteins – evidence of myeloma (plasmocytoma)
Tumor marker NSE = neuron-specific enolase in Ewing’s sarcoma

Magnetic resonance imaging (MRI) In addition to the imaging procedures mentioned in the basic diagnostics, magnetic resonance imaging is another option that may be used in individual cases. MRI (magnetic resonance imaging) is particularly good at imaging soft tissue, allowing the tumor to be shown to extend to neighboring structures (nerves, vessels) of affected bones. In addition, MRI (magnetic resonance imaging) can be used to estimate the tumor volume and clarify the local tumor extent.

As soon as a malignant bone tumor is suspected, the entire tumor-carrying bone should be imaged to exclude metastases (malignant metastases). Computed tomography (CT): (especially for imaging hard (cortical) bone structures) Positron emission tomography (PET) (not yet sufficiently valid) Digital subtraction angiography (DSA) or angiography for imaging the tumor vessels Skeletal scintigraphy (3-phase scintigraphy) Biopsy As mentioned above, the distinction between Ewing’s sarcoma and osteomyelitis, for example, can be quite difficult. In addition to the fact that the symptoms are similar, the X-ray image as such cannot always provide direct information.

If, after the so-called non-invasive diagnostics described above, there is still suspicion of a tumor or uncertainty about the type and dignity of a tumor, a histopathological examination (= fine tissue examination) should be performed. Incisional biopsy The tumor is partially exposed surgically as part of the so-called incisional biopsy. Finally, a tissue sample is taken (bone and soft tissue if possible). It is possible to evaluate the removed tumor tissue directly. Excision biopsy (complete removal of the tumor) It is only considered in exceptional cases, for example if there is a suspicion of malignancy (change from a benign to a malignant tumor) of small osteochondromes.