extraskeletal Ewing sarcoma

Extra osseus
Ewings sarcoma / PNET with sacral and sciatic nerve involvement.. A T1 isointense lobulated mass lesion in the presacral space extending through the left greater sciatic foramen into the gluteal region.
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A rare case
report of Extraskeletal Ewing"s sarcoma of the trachea. CT Thorax lung window shows no abnormalities in lung parenchyma.
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A rare case
report of Extraskeletal Ewing"s sarcoma of the trachea. Plain CT Thorax shows a well defined polypoidal soft tissue density lesion in the left anterolateral wall of the trachea at T2 vertebral level with significant luminal narrowing and mediastinal extension
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MRI imaging
of soft tissue tumours of the foot and ankle. Extraosseous Ewing’s sarcoma. a Coronal T1W and (b) sagittal T2FS images of the foot. The lesion is isointense on T1W and hyperintense on T2FS and lies superficial to the plantar fascia
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Extraskeletal
Ewing sarcoma. T1FSW image after contrast administration: the mass demonstrates diffuse enhancement, slightly heterogeneous.
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Extraskeletal
Ewing sarcoma. T2W image reveals a heterogeneous signal intensity mass with areas of both intermediate and high signal intensity.
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Extraskeletal
Ewing sarcoma. T1W image reveals an oval mass obliterating the Kager fat pad. The mass demonstrates intermediate to high signal intensity. The posterior tibial nerve can be seen apparently entering the lesion (arrow).
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Extraskeletal
Ewing sarcoma. STIR image demonstrates a hyperintense lesion.
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Extraskeletal
Ewing sarcoma. US reveals an hypoechoic oval soft-tissue mass with internal vascularization at Colour Doppler US. Posterior tibial nerve can be seen apparently entering the lesion (arrows).
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Extraskeletal
Ewing sarcoma. Radiographs show an osteochondroma (white arrow) and a soft-tissue mass, not seen in the AP projection, obliterating the Kager fat pad (pink arrows).
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Tumor and
tumorlike conditions of the pleura and juxtapleural region: review of imaging findings. Diagnosis: extraskeletal Ewing sarcoma. Technique: standard chest radiography and contrast-enhanced chest CT. Description: A 17-year-old man presented with localized right-sided chest pain. Postero-anterior and lateral chest radiographs (a, b) show a well-delineated mass located posterior in the right lung. Axial contrast-enhanced CT (c) in the mediastinal window setting shows a heterogeneous mass with intralesional necrosis and focal bony destruction of the corpus of the vertebra, pedicle, and the posterior side of the rib (arrows), best seen in the bone window (d). The young age of the patient, locoregional bone destruction, and extensive soft tissue component is suggestive of an extraskeletal Ewing sarcoma
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Extraskeletal
Ewing sarcoma • Ewing sarcoma/primitive neuroectodermal tumor (PNET) - thigh - Ganzer Fall bei Radiopaedia
Haouimi A, Ewing sarcoma/primitive neuroectodermal tumor (PNET) - thigh. Case study, Radiopaedia.org (Accessed on 01 Aug 2023) https://doi.org/10.53347/rID-147029 • CC by-nc-sa 3.0 (modified)
Radiopaedia • CC-by-nc-sa 3.0 • de

Extraskeletal Ewing sarcoma (EES) is included in the Ewing sarcoma family of tumors (ESFT) along with Ewing sarcoma of bone, primitive neuroectodermal tumor (PNET), peripheral neuroepithelioma, and thoracopulmonary PNET (Askin tumor). When compared with Ewing sarcoma of bone, extraskeletal Ewing sarcoma is rare.

Epidemiology

EES is generally found in younger patients (in 85% between the age of 20 months and 30 years). Osseous Ewing sarcoma is estimated to be about 5 to 6 times more prevalent than ESS , however, in adults at least half of primary cases are extraskeletal.

When compared with Ewing sarcoma of bone, EES displays several differences :

  • no distinct male predilection, but instead a more equal distribution between sexes
  • slightly older age group than found in osseous Ewing sarcoma by 5-10 years, the average age is 20 years of age
  • the trunk is affected more frequently than the lower extremities

Clinical presentation

A rapidly growing, solitary, superficial or deep mass in the soft tissues is generally seen between 5 and 10 cm at the initial presentation . Depending on where the tumor is located, adult patients generally present with a painless mass or vague abdominal or chest pain . If the mass is seen to be paravertebral, the patient can present with symptoms of cord compression . Between 35% and 43% of adult patients have metastatic disease at presentation . The most common site of metastasis is the lung.

Pathology

Location
  • paravertebral region (~30%)
  • lower extremities (~25%)
  • chest wall (~20%)
  • retroperitoneum (~10%)
  • pelvis and hip (~10%)
  • upper extremities (3%)
  • intracranial

Radiographic features

Extraskeletal Ewing sarcoma imaging features are generally nonspecific.

Plain radiograph
  • normal appearance
  • large soft-tissue mass (50%)
  • calcification (25%)
  • presence of adjacent bone erosion, cortical thickening, osseous invasion, or periosteal reaction
CT

  • nonspecific soft-tissue mass of similar attenuation to muscle (87%)
  • low attenuation can be due to hemorrhage or necrosis
  • calcification (25-30%)
  • osseous involvement of bone surface with cortical erosion or periosteal reaction (40%)
MRI

A common feature is disorganized high-flow vascular channels with low signal intensity with all pulse sequences (90%). Additionally, a pseudocapsule with somewhat well-defined margins can be seen (36%) .

  • T1
    • soft tissue mass with heterogenous signal intensity (~90%)
    • similar intensity to skeletal muscle
  • T1 C+ (Gd)
    • heterogeneous but prominent enhancement
  • T2
    • intermediate to high signal intensity (100%)
    • fluid levels may be evident
Nuclear medicine

Bone scintigraphy and FDG PET shows increased radionuclide uptake.

Ultrasound

  • most frequently hypoechoic
  • increased Doppler blood flow

Treatment and prognosis

Local disease starts with neoadjuvant chemotherapy as the standard of care before definitive radiation or surgery. EES is aggressive with a high propensity for local recurrence and distant metastasis. Recurrence occurs in ~30% (range 22-36%) .Adult outcomes may be worse than in children, because of the inability of adults to tolerate aggressive chemotherapy.

Differential diagnosis

General imaging differential considerations include

Siehe auch:
und weiter:
Assoziationen und Differentialdiagnosen zu extraossäres Ewingsarkom:
Ewing-Sarkom
 
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