Histopathology reports

Ultrasound-guided core biopsy: Ewing sarcoma

  • malignant round cell tumor consisting of nests of cells forming an anastomosing network of
    tumor cells. Extensive necrosis with acute inflammation. Features are consistent with Ewing sarcoma
  • follow-up immunostains show diffuse dot-pattern positivity for vimentin with rare CAM5.2 positive tumor cells. Diffuse membrane-cytoplasmic positivity for CD99. FISH and FLI-1 studies will be followed, but findings are those of Ewing sarcoma


Subsequent rib resection: Ewing sarcoma, post-treatment with 20% viable cells

  • external surface notable for a masslike lesion abutting chest wall measuring approximately 4.5 x 3.3 x 2.1 cm with an adjacent apparent fracture and rupture of the chest wall measuring 3 x 0.5 cm, though this may be an artifact of surgical manipulation
  • attached soft tissue along margins comprised of muscle and fat
  • sectioning reveals portions of extensive crumbling necrosis of the bone as well as extension of apparent dark gray necrotic areas of bone comprising approximately 30% of the total bone mass submitted