Extramedullary presentation of blast crisis in chronic myelogenous leukemia.

We present a case with the clinical and pathological impression of Ph1-positive chronic myelogenous leukemia in extramedullary blast crisis involving lymph nodes as demonstrated by morphological and cytogenetic studies. The hyperploid cell lines that were present in the lymph node were not present in the bone marrow. The present case demonstrates that cytogenetic and morphological studies of extramedullary organs are helpful in the confirmation of the diagnosis of blast crisis, especially when lymph nodes are the site of original presentation.