12-year-old boy suffering from pain and swelling in the area of the thigh. The X-ray shows permeative, patchy osteolysis in the area of the femur diaphysis and a reaction of the periost: onion bulb formation, Codman`s triangle. Biopsy.
- Neoplastic infiltrate in the bone marrow space, canalicular system and paraosteal soft tissue: small to medium sized round cells with little cytoplasm, round nuclei and medium sized nucleoli. Few mitoses. Glycogen granula can be seen.
- Note the destruction of the bone structure.
The occasional clinical presentation with warmth and reddening of the affected area, pyrexia and leucocytosis can mimic osteomyelitis.
Diagnosis: Other neoplasms of the “round cell sarcoma” type must be excluded, such as malignant lymphoma, neuroblastoma and embryonal rhabdomyosarcoma.
Immunohistochemical analysis includes the following:
-LU-5 Antibody: cytokeratin