Neurolymphomatosis is the direct endoneurial infiltration of lymphoma cells. Bone marrow biopsy is a widely practiced procedure that is generally considered to be relatively safe. However, bone marrow biopsy can also result in pain and long-term consequences such as nerve injury. Here we report a case of a 68-year-old male who presented with lumbosacral plexopathy due to neurolymphomatosis that was superimposed on a probable traumatic lumbosacral plexopathy mostly involving the sciatic nerve immediately after a bone marrow biopsy.

Chronic graft-versus-host disease (GVHD) is a well-known complication of allogeneic bone marrow transplantation (BMT)and has heterogeneous manifestations, with multi-organ involvement. Recently, polymyositis (PM) was reported to be a raremanifestation of chronic GVHD. Here, we report a 30-year-old woman who was diagnosed with PM after allogeneic BMT.