Ewing sarcoma

Ewing sarcoma
Updated: 08/12/2022
© Jun Wang, MD, PhD

General features
  • AKA primitive neuroectodermal tumor (PNET)
  • #2 bone sarcoma in children, after osteosarcoma
  • Usually whites, ages 5-20 years
  • Possible multiple lesions at presentation
  • 5 year survival near 75%
Clinical presentations
  • Pain, fever, weight loss
Most common sites
  • Medullary cavity, usually shaft
  • Femur, tibia, humerus, etc
Key pathogenesis
  • EWS-Fli1 activates Cyclin D and Cyclin E
  • Activation of Cyclin D and Cyclin E promotes cell cycle progression through suppression of tumor suppressor RB
Key radiologic findings
  • Mottled, osteolytic lesion with sunburst periosteal reaction
  • Lamellated periosteal reaction
  • Codman’s triangle: Shadow between cortex and raised ends of periosteum (due to reactive bone formation), non-specific (can be seen in osteosarcoma)
Key morphological features
  • Sheets of small blue cells with scant cytoplasm and round nuclei
Markers
  • Positive for CD99
Differential diagnosis
  • Lymphoma: Positive for CD45, CD20 if B cell, CD3, etc if T-cell, but negative for CD99
  • Small cell carcinoma: Positive for cytokeratin and neuroendocrine markers such as chromogranin, synaptophysin and CD56
Genetic abnormalities
  • t(11,22)(q24;q12)/EWS-FLI1
Treatment
  • Surgery
  • Chemotherapy
  • Radiation


Back to bone tumors
Back to contents

Comments

Post a Comment

Popular posts from this blog

Contents

Pathology notes Jun Wang, MD, PhD 1. General information Frequently discussed syndromes Terms of dermatology Terms of hematology 2. Primary immunodeficiency disorders 3. Hemodynamic abnormalities Shock Thrombosis and embolism Bleeding disorders 4.  Benign blood cell disorders Anemia Benign white cell disorders 5. Hematopoietic neoplasms Lymphoid neoplasms Myeloid neoplasms Histiocytic neoplasms: Langerhans cell histiocytosis 6. Cardiovascular system Pulmonary hypertension Cardiovascular system tumors 7. Respiratory tract tumors 8. Gastrointestinal tract Congenital disorders Infectious gastroenteritis Oral cavity Esophagus Stomach Intestinal tumors Salivary glands Exocrine pancreas and gallbladder 9. Urinary system Kidney masses Lower urinary tract 10. Male reproductive system 11. Female genital tract 12. Breast 13. Endocrine organs Pituitary gland Adrenal gland Thyroid gland Parathyroid gland Endocrine pancreas M
Read more

Anemia

Anemia Updated: 07/13/2024 © Jun Wang, MD, PhD   General features Decrease in red cell mass Hemoglobin: Levels of hemoglobin in a specific volume of whole blood Hematocrit: Fraction of whole blood composed of red blood cells Red cell count: Quantity of red cell in a specific volume of whole blood Three major groups based on RBC sizes Microcytic Normocytic Macrocytic Three major causes Blood loss: acute or chronic Increased red cell destruction: hemolysis Reduced production: marrow failure due to genetic abnormality or nutritional deficiency Etiology Genetic abnormality Hemoglobinopathies RBC cytoskeletal abomorlities Enzyme abnormalities Fanconi anemia Nutritional deficiencies: iron, VB12, folate, general malnutrition Physical etiologies: trauma, burns, frostbite, prosthetic valves, etc Chronic diseases: chronic infections, neoplasia, autoimmune disorders, kidney or liver diseases, etc Infectious diseases: hepatitis, sepsis , malaria, etc
Read more

Lymphoid neoplasms

Lymphocytic neoplasms Updated: 05/17/2020 © Jun Wang, MD, PhD Terminology Lymphoma : Proliferations forming discrete tissue masses Leukemia : Widespread involvement of the bone marrow and usually the peripheral blood Any "lymphoma" can present with or evolve to a leukemic picture, and any "leukemia" can occasionally present with a mass lesion Other hematology terms Important risk factors Immunodeficiency (primary or secondary) Autoimmune disorders Viruses (HIV, KSHV/HHV8, HTLV-1) H. pylori infection Radiation Chemotherapy Diagnostic approaches Complete history, especially those with possible epidemic characters, such as Burkitt lymphoma CBC, Bone marrow Morphology/immunohistochemistry Immunofluorescence flow cytometry Cytogenetic studies Molecular studies Commonly used markers All lymphomas: CD45 B-cell neoplasms: CD5, CD10, CD19, CD20, CD79a, CD23, bcl2, bcl6, cyclin D1, light chai
Read more