Anaplastic large cell lymphoma is a rare malignancy in childhood. We d
escribe the case of a 6-year-old boy with Ki-l lymphoma of the thymus
who presented with an endocardiac mass. The first histologic analysis
suggested a high-grade undifferentiated sarcoma, but reevaluation and
immunohistochemistry confirmed the CD30(+) lymphoid derivation of the
process. The patient was given chemotherapy and 24 months later he rem
ains in complete remission. It is noted that echocardiography was repe
ated many times to detect heart lesion.