Ewing's Sarcoma: An Uncommon Breast Tumor

Ewing sarcoma: A pictorial review of typical and atypical locations with reference to the updated 2020 WHO classification system

Ewing sarcoma (ES) is a small round cell sarcoma which usually occurs in the paediatric and young adult age groups. This pictorial review briefly discusses and presents the typical skeletal and extraskeletal locations which ES is encountered, including the metadiaphysis of long bones, pelvis, chest wall and paravertebral regions. Five cases of ES in atypical locations are then presented along with an observation of demographic differences between skeletal and extraskeletal ES. These cases include ES arising from the metatarsal, scapula, breast, intracranial soft tissue and the paranasal sinuses. Presenting symptoms, treatment approach and prognosis are highly variable depending on the location; and multimodal imaging is centrepiece in the management process. Management usually includes any combination of chemotherapy, radiotherapy and surgery. The WHO classification system was updated in 2020 to include some of the rare genetic subtypes of ES. One such case of the BCOR subtype is demonstrated in this review and occurs in an atypical location. Whether these subtypes have distinct radiological features or a propensity to occur in atypical locations is an area for further research.

Ewing’s Sarcoma of the Breast in a Young Woman: A Case Report and Review of the Literature

Ewing’s Sarcoma Family Tumors (ESFT) include classic Ewing’s sarcoma of bone, extra-skeletal Ewing’s sarcoma (EES), malignant small cell tumor of the chest wall (Askin tumor), and soft tissue-based Peripheral Primitive Neuroectodermal tumors (pPNET). The t(11;22)(q24;q12) translocation is associated with 85% of tumors and leads to EWS-FLI-1 (Ewing’s Sarcoma–Friend Leukemia Integration-1) formation. This is a potent transforming gene that encodes a chimeric protein that plays a role in the genesis of Ewing’s Sarcoma and Primitive Neuroectodermal Tumors. The breast location of ESFT remains exceptional. The prognosis is among the poorest of all subtypes of breast cancer and even poorer than other extraosseous Ewing’s sarcomas. We describe the case report of a 23-year-old patient with a growing breast lump, who required an accurate and challenging diagnostic estimation and who ultimately resulted in a peripheral primary neuroectodermal tumor (pPNET). Through this case description and a brief narrative review of the literature, we aim to highlight the rarity of ESFT located in the breast. Histopathological confirmation is mandatory for all growing masses of the breast to reach a conclusive diagnosis and plan the correct treatment. Patients with rare diagnoses should always be centralized in breast units, conducting multidisciplinary meetings and, when necessary, the diagnosis should be shared through wider national or international registries.

Extraskeletal Ewing Sarcoma from Head to Toe: Multimodality Imaging Review

Extraskeletal Ewing sarcoma (EES) is a rare subtype in the Ewing sarcoma family of tumors (ESFT), which also includes Ewing sarcoma of bone (ESB) and, more recently, primitive neuroectodermal tumors. Although these tumors often have different manifestations, they are grouped on the basis of common genetic translocation and diagnosis from specific molecular and immunohistochemical features. While the large majority of ESFT cases occur in children and in bones, approximately 25% originate outside the skeleton as EES. Importantly, in the adult population these extraskeletal tumors are more common than ESB. Imaging findings of EES tumors are generally nonspecific, with some variation based on location and the tissues involved. A large tumor with central necrosis that does not cross the midline is typical. Despite often nonspecific findings, imaging plays an important role in the evaluation and management of ESFT, with MRI frequently the preferred imaging modality for primary tumor assessment and local staging. Chest CT and fluorine 18 fluorodeoxyglucose PET/CT are most sensitive for detecting lung and other distant or nodal metastases. Management often involves chemotherapy with local surgical excision, when possible. A multidisciplinary treatment approach should be used given the propensity for large tumor size and local invasion, which can make resection difficult. Despite limited data, outcomes are similar to those of other ESFT cases, with 5-year survival exceeding 80%. However, with metastatic disease, the long-term prognosis is poor. ^©RSNA, 2022.