Ki-1+ large-cell anaplastic lymphoma after Ewing sarcoma

Purpose: A large cell anaplastic lymphoma that developed after treatment of a Ewing sarcoma (ES) is described. Patient: An 11-year-old girl with a pelvic ES developed a large cell, Ki-1, anaplastic lymphoma in the same anatomic location 10 months after multimo dal therapy. Results: ES recurred in the primary site 16 months after allogeneic marrow transplantation and 3.5 years after initial diagnosis, but the patient rema ins in remission from her lymphoma. Conclusion: The occurrence of lymphoma and ES in a short time interval in t he same patient is very unusual. Whether etiologic factors other than chemo radiotherapy, including genetic disposition, play a role remains to be eluc idated.