Rhabdomyosarcoma Involving Bone Marrow

Lessons From The Friday Unknowns

The patient is a 17 year old female with recurrent alveolar rhabdomyosarcoma.

The bone marrow biopsy shows a variably cellular bone marrow with decreased trilineage maturing hematopoesis and ~40–50% involvement by metastatic tumor cells by desmin stain. In addition, per submitted pathology report, fluorescence in situ hybridization is positive for a FOXO1 rearrangement.