Abstract
Ewing sarcoma is the most common malignant bone tumor of the pelvis in children and
young adults. Even with aggressive treatment, its survival rate is amongst the poorest.
Classical presentation may not be the rule. It may simulate clinically, imagiologically
and histopathologically other nonmalignant entities. Therefore, its suspicion should
not be overlooked. We report two cases of pelvic Ewing sarcoma: the first mimicking
eosinophilic granuloma, and the second mimicking osteomyelitis. In the latter, we
also report an atypical finding of its natural history: an initial response to antibiotic
and anti-inflammatory treatment. In both cases, we highlight the possibility of an
inconclusive percutaneous bone biopsy and the importance of immunochemistry and cytogenetics
for the definitive diagnosis.
Keywords
sarcoma, Ewing - pelvic neoplasms - eosinophilic granuloma - osteomyelitis - anti-onflammatory
agents, non-steroidal
