The Ewing’s sarcoma family of tumors comprises high-grade small round cell tumors, predominantly affecting children and primarily found in bones. However, approximately 25% of these tumors occur outside the skeleton, termed Extraskeletal Ewing’s sarcoma (EES). EES remains relatively rare and is more commonly observed in adults compared to children. These tumors share a common genetic lineage, often characterized by the fusion of Ewing’s sarcoma gene (EWSR1) with various transcription factors. The diagnosis of EES relies on histopathological and immunohistochemical analysis due to nonspecific imaging features. Herein, we present a case series of EES, highlighting its diverse manifestations and diagnostic challenges. [1] [5]

1.       PRIMARY RENAL EWING’S SARCOMA :-

A 15-year-old male patient presented to our department complaining of right flank pain and hematuria. A contrast-enhanced computed tomography (CECT) scan of the abdomen and pelvis with renal dynamic protocol was performed, revealing a hypodense mass lesion involving the upper and mid pole of the right kidney, with a few foci of calcification noted on plain study. The lesion exhibited minimal to mild enhancement in the corticomedullary, excretory, and nephrogenic phases, with internal non-enhancing necrotic areas observed within. Additionally, a hypodense filling defect was noted in the right renal vein extending into the infra and intrahepatic inferior vena cava (IVC), suggestive of a tumoral thrombus. Biopsy was recommended, and histopathological correlation confirmed the diagnosis of primary Ewing’s sarcoma of the kidney. The patient underwent chemotherapy, resulting in a decrease in tumor size. Subsequently, radical nephrectomy with thrombectomy and IVC graft repair were performed. [1]

IMAGING FINDINGS

[Figure 1.1] Plain study showing hypodense mass lesion involving upper and mid pole showing few foci of calcification. There is minimal enhancement in corticomedullary and nephrogenic phase and mild enhancement in excretory phase. Mild perirenal fat stranding is noted.

[Figure 1.2] There is hypodense filling defect noted in right renal vein extending into infra and intrahepatic IVC, s/o tumoral thrombus. Renal artery appears free from the lesion. There is non excretion of contrast in delayed phase, suggestive of delayed function or non functional kidney.

2.       PRIMARY EWING’S SARCOMA OF RIGHT MAXILLARY SINUS :-

Primary Ewing’s sarcoma of the maxillary sinus is a rare occurrence, often characterized by the presence of a mass within the maxillary sinus with potential extension into the orbit or medially into the nasal cavity. Here, we describe the case of a 48-year-old female who presented with a mass in the right maxillary sinus. Computed tomography (CT) imaging revealed a heterogeneously enhancing soft tissue density lesion involving the right maxillary sinus, accompanied by thinning of all sinus walls and cortical breaks at various locations. Magnetic resonance imaging (MRI) was subsequently conducted to rule out intra-orbital extension and to further characterize the lesion. [1] [4]

IMAGING FINDINGS:

3.       PRIMARY EWING’S SARCOMA OF SUPRAGLOTTIS :-

Primary Ewing sarcoma of the larynx is exceedingly rare, with only eight documented cases reported worldwide until 2020, three of which occurred in the paediatric age group. Here, we present a case involving an 8-year-old boy who presented to the emergency department with acute respiratory distress. Upon history-taking, the patient reported experiencing a change in voice over the preceding three months. Emergency tracheostomy was performed to alleviate the respiratory distress. Subsequent laryngoscopy revealed the presence of a mass within the larynx. Biopsy results indicated a malignant high-grade tumour, prompting referral to GCRI for further management.

At our institute, a biopsy was repeated, and immunohistochemistry (IHC) analysis confirmed the diagnosis of Ewing’s sarcoma.  [1]

Baseline imaging and disease staging were performed using MRI.  [4]

IMAGING FINDINGS:

4.       PRIMARY PNET OF SCAPULA:-

Thoraco-pulmonary extra skeletal Ewing’s sarcoma (EES) is a rare occurrence, particularly in the paediatric age group and even more so in adults. These tumors are also referred to as primitive neuroectodermal tumours (PNET) or Askin tumours. They often manifest as chest wall masses and may be accompanied by symptoms such as cough, respiratory distress, or weight loss. Radiologically, they can present as aggressive pleural-based or chest wall masses, sometimes with ipsilateral mediastinal lymphadenopathy. [1]

Here, we present the case of a 22-year-old male patient who presented with a left chest wall mass. CT of the thorax revealed a lytic destructive lesion involving the left scapula, with an associated soft tissue component. Subsequent MRI was performed to provide better characterization of the lesion and to delineate any intra-articular extension. Biopsy results confirmed the diagnosis of Ewing’s sarcoma/PNET. [1]

IMAGING FINDINGS:

5.       PRIMARY ABDOMINAL EWING’S SARCOMA :-

Abdominal extraskeletal Ewing’s sarcoma (EES) is an exceptionally rare occurrence. Patients with primary abdominal masses may exhibit various presentations, including peritoneal masses, omental nodules, or ascites, with possible associated retroperitoneal masses. Here, we present the case of a 6-year-old female who presented with an abdominal mass accompanied by multiple metastases to the lung, liver, omental deposits, bone metastases, and gross ascites. Subsequent biopsy revealed tumor cells that were immunoreactive for NKX2.2, CD99, and FLI1, while immunonegative for LCA, effectively ruling out lymphoma. [1] [2,3]

IMAGING FINDINGS:

6.       PRIMARY BREAST EWING’S SARCOMA :-

A 22 year old lady came to our department with complain of mass in left breast. Breast imaging was done. Mammosonograph of both breastperformed ,showing large lobulated  mass with internal calcifications and vascularity in upper outer quadrant which extending into inner quadrant and retroareolar region ofleft breast. In Computed tomography scan of this breast performed showing heterogenously enhancing lesion is noted. Subsequent biopsy of this mass reveals Ewing’s sarcoma (EES) is an exceptionally  occurrence. Subsequent biopsy revealed tumor cells that were immunoreactive for NKX2.2, CD99, and FLI1, while immunonegative for LCA, effectively ruling out lymphoma. [1] [2,3,5]

IMAGING FINDINGS:

Extraskeletal Ewing’s sarcoma (EES) is a rare occurrence, often presenting challenges in differentiation based on imaging characteristics. Typically, imaging reveals nonspecific findings, with most cases displaying heterogeneous soft tissue masses accompanied by necrosis and hemorrhage. Additionally, EES may exhibit secondary involvement of the bone surface, evidenced by cortical erosion or periosteal reaction. While CT is commonly employed for EES investigation, MRI may be utilized in select cases to enhance lesion characterization. [1] [4]

Differential diagnoses for extra osseous Ewing’s sarcoma encompass various conditions, including rhabdomyosarcoma in peritoneal or extremity masses, synovial sarcoma typically observed in juxtaarticular regions, neuroblastoma in adrenal or paravertebral locations, and extra skeletal mesenchymal tumours like chondrosarcoma in head and neck lesions. [1]

The definitive diagnosis of EES necessitates histopathological correlation, either pre or post-operation, revealing characteristic small round blue cells.

Immunohistochemical analysis typically exhibits the presence of neuro-ectodermal markers such as neuron-specificenolase, synaptophysinFLI1 (Friend Leukemia Integration 1) and NKX2. CD99 (also referred to as MIC2): CD99, a cell surface glycoprotein exhibits strong positivity in EES and is considered one of the most reliable diagnostic markers for this condition.

Approximately 25% of EES patients present with metastatic disease, most commonly involving the lungs. Bone metastases are also frequently encountered, while brain and liver metastases are less common. Some cases may exhibit associated regional metastatic lymphadenopathy.  [2,3]

For cases of metastatic disease, FDG PET/CT scans are routinely conducted to aid in staging and characterization. Treatment strategies for Ewing’s sarcoma family of tumors typically involve a combination of radiotherapy and chemotherapy, given their known radiosensitivity and chemosensitivity..

Extraskeletal Ewing’s sarcoma presents with diverse imaging features and should be considered in the differential diagnosis of large soft tissue masses, particularly in younger patients. Definitive diagnosis relies on histopathological examination, with imaging playing a crucial role in staging and management decisions. [1] [4]

1.       Javery O, Krajewski K, O'Regan K et al. A to Z of Extraskeletal Ewing Sarcoma Family of Tumors in Adults: Imaging Features of Primary Disease, Metastatic Patterns, and Treatment Responses. AJR Am J Roentgenol. 2011;197(6):W1015-22.

2.       El Weshi A, Allam A, Ajarim D et al. Extraskeletal Ewing's Sarcoma Family of Tumours in Adults: Analysis of 57 Patients from a Single Institution. ClinOncol (R Coll Radiol). 2010;22(5):374-81.

3.       Imaging Features of Primary Tumors and Metastatic Patterns of the Extraskeletal Ewing Sarcoma Family of Tumors in Adults: A 17-YearExperience at a Single Institution Korean J Radiol. 2015 Jul-Aug; 16(4): 783–790. Published online 2015 Jul. doi: 10.3348/kjr.2015.16.4.783

4.       Murphey MD, Senchak LT, Mambalam PK, Logie CI, Klassen-Fischer MK, Kransdorf MJ. From the radiologic pathology archives: ewing sarcoma family of tumors: radiologic-pathologic correlation. Radiographics. 2013;33:803–831

5.       Somarouthu BS, Shinagare AB, Rosenthal MH, Tirumani H, Hornick JL, Ramaiya NH, et al. Multimodality imaging features, metastatic pattern and clinical outcome in adult extraskeletal Ewing sarcoma: experience in 26 patients. Br J Radiol. 2014;87:20140123 [5]