A RARE CASE OF ATYPICAL PRIMARY EWING???S SARCOMA OF OCCIPITAL BONE

Abstract

K. Srihari1, Pogaku Mounika Bindu2, Kuchukulla Venkat Ramreddy 3, (Brig.) R. Sathyanarayana Moorthy4, Gaddam Ramakrishna Reddy5

BACKGROUND
Ewing’s Sarcoma is an aggressive malignant neoplasm most frequently manifesting in the second decade of life and accounting for 4% of childhood and adolescent malignancies. These tumours were first described by James Ewing in 1921 as tumours that arise from bone. These osseous lesions have since become infamous for their highly aggressive course with 20% to 30% of patients having evidence of metastasis at the time of diagnosis and an estimated 10-year survival rate of 50%. Metastases to the CNS have most recently been estimated to occur in less than 5% of cases and are usually due to direct extension of an osseous lesion into the extradural space or more rarely through haematogenous spread.
CASE REPORT
In this article, we report a case of 17-year-old boy who presented to the radiology department with complaints of recurrent episodes of headache and vomiting for the past 3 days. On radiological investigation, there was a large well-defined, lobulated, extra-axial mass lesion measuring 3.6 X 5.7 X 5.9 cm noted in the supratentorial left occipital region which was fairly enhancing after contrast administration. The mass was causing permeative type of destruction of the left occipital bone and extending into extracranial soft tissue. Final diagnosis was done by biopsy and histopathology which showed “Atypical Ewing’s Sarcoma” of the left occipital bone. Considering its unusual site and soft tissue extension, we report this case of Primary Atypical Ewing’s sarcoma of occipital bone.
CONCLUSION
Primary cranial Ewing's sarcoma is to be considered in the differential diagnosis in children with a tumour involving the skull with destruction of the bone and presence of extra-axial soft tissue swelling. CT is the excellent modality for demonstration of bone destruction while MRI depicts soft tissue extension and metastasis if any.

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