Ki-1-positive large-cell anaplastic lymphoma with protean manifestations including central nervous system involvement.

A 26-year-old female with Ki-1-positive large-cell anaplastic lymphoma is reported. The neoplastic cells were phenotypically and genotypically of T cell origin. Initially, neoplastic cells invaded the skin and lymph nodes, and then invaded the sternal and vertebral bones, ribs and the iliopsoas muscle. Central nervous system (CNS) involvement with paraplegia, large tumor mass formation in her breast and pleural infiltration ensued in succession. This case illustrates the protean manifestations of Ki-1-positive large cell anaplastic lymphoma complicated with CNS involvement.