Ewing sarcoma arising after treatment of diffuse large B-cell lymphoma

We report the case of a patient in whom the diagnosis of Ewing sarcoma arising from a soft tissue was made after successful treatment of diffuse large B-cell lymphoma. A 65-year-old woman presented with a rapidly growing mass in her left scapular region 8 years after successful chemotherapy with the cyclophosphamide, hydroxydaunomycin hydrochloride, vincristine, prednisolone regimen for diffuse large B-cell lymphoma. Computed tomographic examination and magnetic resonance imaging of the thorax revealed an intramuscular tumour measuring 40 mm in size in the left scapular region. Histopathological examination of an open biopsy specimen revealed a small round cell tumour that showed positive staining for CD99. Fluorescence in situ hybridization showed a split signal by a break-apart probe for the EWS gene in chromosome 22q12. Reverse transcriptase-polymerase chain reaction confirmed the expression of EWS-FLI1 fusion transcripts. Based on these findings, the patient was diagnosed as having secondary Ewing sarcoma. Despite adjuvant chemotherapy, however, she died of pulmonary metastases 2 years after the diagnosis of Ewing sarcoma. Therapy-related haematological malignancies with balanced translocations have been reported previously. A mechanism similar to that underlying the development of secondary malignancy might explain the occurrence of this solid cancer.