As already mentioned above, Ewing’s sarcoma is considered to have metastasized at an early stage hematogenically (= via the bloodstream). Metastases can therefore also settle in the soft tissue. The lung is primarily affected by this.
However, the skeleton can also be affected by metastases via the bloodstream. The fact that Ewing’s sarcoma can be classified as an early metastasis 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 shall 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
- Swelling of lymph nodes
- Local signs of inflammation (redness, swelling, overheating)
- Unwanted 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 can be proven 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 tumour localisation (at least 2 levels) Sonography Sonography of the tumour (especially in the case of differential diagnostic suspicion of soft tissue tumour) Laboratory diagnostics (examination of laboratory values) is used to obtain additional information and to enable differential diagnostic delimitations. The following values are determined within the scope of this laboratory diagnosis:
- 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 haemoblastosis
- 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. By means of MRI (magnetic resonance imaging), the soft tissue can be depicted particularly well, allowing the tumour to be shown to extend to neighbouring 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 tumour is suspected, the entire tumour-bearing bone should be imaged in order to rule out 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 can be quite difficult.
Apart from 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 tumour or uncertainty about the type and dignity of a tumour, a histopathological examination (= fine tissue examination) should be carried out. Incisional biopsy In the course of the so-called incisional biopsy, the tumour is partially exposed surgically.
Finally, a tissue sample is taken (if possible bone and soft tissue). It is possible to assess the removed tumour tissue directly. Excision biopsy (complete removal of the tumour) It is only considered in exceptional cases, for example if there is a suspicion of malignancy (change from a benign to a malignant tumour) of smaller osteochondromes.