Ewing’s Sarcoma

Ewing’s Sarcoma

– small round cell tumor of bone occurring during adolescence
– can appear anywhere in the skeleton but usu pelvis & long tubular bones
– undistinguishable from PNET (primitive neuroectodermal tumor of bone)

Signs & Symptoms:
– pain & swelling at tumor site +/- tender soft tissue mass
– may have associated fever with elevated WBC & anemia

Xrays:
– poorly marginated, permeative lytic lesion of medullary cavity
– periosteal new bone formation with �onion-skin� pattern

Histology:
– very cellular with minimal matrix production
– small, round, closely packed cells with round uniform nuclei, indistinct cell membranes & scant cytoplasm
– arranged in dense sheets or nests separated by thin fibrous septa
– may have rosette-like structures in which center contains necrotic cells

Treatment:
– neoadjuvant chemootherapy
– wide excision (amputation vs limb salvage)
– radiation may be combined with chemotherapy to treat visceral & lymphatic metastases
– 5 yr survival = 40%