A 5-year old boy presents with pain and swelling in diaphysis of tibia. He also complains of fever. On examination, his ESR was raised. Which of the following is the likely diagnosis?
Correct Answer: Ewing sarcoma
Description: Ans. a. Ewing sarcoma (Ref: Apley 9/e pe p 212-13; Turek's 6/e pe p 307; Campbell's 11/e pe p 910-913; Harrison's 19/e 119e-4, 18/e pe p820)A 5-year old boy presents with pain and swelling in diaphysis of tibia. He also complains of fever. On examination, his ESR was raised. Ewing sarcoma is the most likely diagnosis.Ewing's SarcomaArises from endothelial cells of the bone marrow in the diaphysis (medullary cavity) of long tubular bonesQ (especially femur) and flat bones of pelvis.Highly malignant, undifferentiated peripheral primitive neuroectodermal tumor (PNET)MC site: Diaphysis of femurQ >fibula > ilium > tibia.Pathology:Arising in medullar cavity usually invade the cortex, and periosteum producing a soft tissue massQ.Composed of sheets of uniform, small round cellsQ (that are slightly larger than lymphocytes), with pale clear appearing cytoplasm due to presence of glycogenQ.Cytoplasm is PAS positive and diastase digestibleQ.Presence of Homer-wright rosettes and pseudo rosette is indicative of neural differentiation (i.e. PNET)Express MIC 2 gene in very high amount, distinguish from other round cell tumorsQ.Most definitive test: Demonstration of chromosomal translocation by karyotyping or RT- PCR detection of t(11 : 22).80- 95% patients have a translocation mostly t (11: 22) > t (21 : 22) and rarely t (7 : 22)QEwing sarcomas are periodic acid Schiff positive (owing to intracellular glycogen) and reticulin negative.Clinical Feature:Mostly in males between 10-20 years of ageQ.Pain, swelling, tenderness, urinary/rectal complaints (when ilium involved) pathological fracture.Systemic symptoms such as fever, generalized weakness, weight loss, and lab anomalies as anemia, leukocytosis and raised ESRQ are hallmark of fulminating course, advanced disease or metastasis.50% of all metastases occurs to lungQ and 25% to bone and bone marrowDiagnosis:Mottled rarefaction of spongiosa with permeation of overlying cortex, reflecting rapid bone destruction is the principal findingLaminated (layered) periosteal new bone formation known as onion-peel appearanceSoft tissue massQ, indicating neoplasm has perforated cortexTreatment:Highly radiosensitive (melts on radiotherapy)Q but overall survival is not much enhancedChemotherapy is much more effective and include vincristine, actinomycin D, adriamycin, ifosfamide and etoposideBest results are achieved by:Preoperative chemotherapy then wide excision (or amputation) if tumor is in favorable site and further chemotherapy for 1 years.Radiotherapy followed by local excision if it is in less accessible site and then further chemotherapy for 1 yearPoor prognostic factors for Ewing's sarcoma* Distant metastases* Advanced and extensive disease with fulminant course.* Large tumor size (> 8cm)* Proximal location* Older age (> 17 years)* Mate gender* Genetic aberrant P-53 expression* Relapse* Early (within < 1 year) relapseHistological grade have no prognostic significance because all Ewing's sarcoma are considered as high grade.Histological response to neoadjuvant chemotherapy is a good prognostic indicator.
Category:
Orthopaedics
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