Saturday 28 July 2012

Spinal epidural Ewing sarcoma with significant cord compression



Epidural spinal cord compression (ESCC) refers to compression of spinal cord or cauda-equina by any pathology, most commonly by benign etiology like protruded disc, focal hyper trophy - ossification of ligamentum flavum. Neoplastic and in Infective Epidural abscess are the other next common causes. Among neoplastic the commonest malignancies involving the spinal epidural space are Metastatic lymphoma, Nerve sheath tumor, Meningiomas, Hemangiomas and Metastases from systemic malignancy. Rarely round cell tumors which can present with ESCC are primary CNS lymphoma, granulocytic sarcoma and extra-osseous Ewing sarcoma.
The presentation in neoplastic causes is predominantly slowly progressive paraplegia with or without pain and bowel bladder dysfunction.
Here I am presenting a case of Spinal Epidural Round cell tumor / Ewing’s sarcoma presented with acute onset paraplegia.

A 11 yo female presented with abrupt onset of weakness in both lower limbs and low back pain.




On admission MRI Dorsal spine shows:
A focal lentiform shaped extra dural soft tissue on sagittal T2 extending from D3 to D5 (5cm in length and 7mm in thickness),
Hypo intense on T1 and iso to hyper intense on T2. Homogenous enhancement on post contrast T1.
Significant cord compression with abnormal intramedullary signals. No abnormal focal cord enhancement on post contrast T1. No similar lesion elsewhere in rest of the whole spine post contrast T1 screening.
Adjacent D4 spinous process show abnormal enhancement on post contrast T1 with a minimal similar soft tissue in left spinalis compartment. Rest of the bone marrow signals normal.

Imaging wise possible DDs: Lymphoma, Sarcoma, Pseudo tumour.
Epidural Abscess and Hematoma - less / unlikely due to homogenous enhancement.

Histopathology report: Ewing’s sarcoma ( Microscopy :  Sections A and B, both shows circular malignant small round 'Blue' cell tumor composed of syncytial aggregates lobular sheets of fairly monotonous appearing small round cells having round to oval hyper chromatic nuceli, finally stippled chromatin and smooth nuclear membranes. The cells have pale ampophilic to eosinophilic cytoplasm with indistinct margins and occasional cells show nucleoli the minimal interstitial stroma shows couple of congested blood vessels and appears eosinophillic granular fibrillary in section B the tumor is seen within the inter trabercular space of bony tissue. No endothelial lined space invasion seen.)

Spinal Epidural Ewing's

Extra-osseous Ewing sarcoma (EOES) is an undifferentiated small round-to-oval cell tumor of uncertain origin. Primary extraosseous Ewing sarcoma is a rare entity, especially in the spinal epidural site. Only 21 cases have been reported in the literature.
It differs in presentation from skeletal Ewing's sarcoma in several respects. The average age of occurrence is around 17 years (range 4-47 years), in contrast to 10 years for skeletal Ewing's sarcoma. EOES, like skeletal Ewing's sarcoma, occurs more commonly in males than females, with a ratio of 2:1. Presentation includes back pain in almost in all patients, paresis of one or both legs in approximately 80% with or without sensory disturbances, bladder and bowel dysfunction. The neurological deficits supposed to be of insidious onset being neoplastic. Rarely acute presentation as in this case.
Lumbar and dorsal region spine is most commonly affected. Cervical involvement is rare.
On MRI these lesions commonly appear isointense to muscle on T1, iso to hyperintense on T2 and show moderate enhancement on contrast-enhanced T1 without bony involvement.
Microscopically, the lesion is composed of sheets of fairly uniform round-to-oval cells. Usually the cells have relatively clear and indistinct cytoplasm but contain large quantities of PAS-positive, diastase-digestible material, indicating high concentrations of glycogen. The tumor cells show diffuse, intense membrane reactivity for CD99 (MIC 2) on immuno-histochemical staining.
In management wide surgical resection with follow-up local irradiation and chemotherapy offer the best chance for long-term disease-free survival.

References:
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Kaspers GJ, Kamphorst W, van de Graaff M, van Alphen HA, Veerman AJ. Primary spinal epidural extraosseous Ewing's sarcoma. Cancer 1991;68:648-54.

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