Dedifferentiated liposarcoma with heterologous rhabdomyosarcomatous differentiation in the bone marrow.

We present a case of advanced well-differentiated liposarcoma transforming to dedifferentiated liposarcoma in the bone marrow.Our patient presented with 5 weeks of worsening flank pain. He was found to have profound leukocytosis, thrombocytopenia, and normocytic anemia. Imaging showed a dominant retrocaval mass concerning for viable disease. Bone marrow biopsy revealed dedifferentiated liposarcoma with heterologous rhabdomyosarcomatous differentiation. He underwent 3 cycles of eribulin and subsequently developed complications of his increasingly aggressive liposarcoma. He was transitioned to hospice care and died 3 months after initial bone marrow biopsy. While exceedingly rare, it is possible for liposarcoma to metastasize to the bone marrow and cause rapid progression to death. In patients with high-grade liposarcoma, new cytopenia, leukocytosis, elevated granulocyte colony stimulating factor, and/or leukoerythroblasosis on peripheral smear should prompt bone marrow biopsy for early detection of this rare disease entity.