NF2 and ATRX gene copy number losses on a case of ovarian ependymoma.

Ovarian ependymomas are rare glial neoplasms that typically occur in females on their 3rd to 4th decade of life. They are histologically similar to ependymomas of the central nervous system (CNS) but may have a broader immunophenotype. We describe a 27year old female who presented to the emergency room with a 3week history of cough and shortness of breath. Further workup disclosed a left pelvic mass and extensive intra-abdominal metastases. Pathology revealed sheets of monomorphic cells within a fibrillary stroma, papillary projections, true ependymal rosettes, and pseudorosettes consistent with an ependymoma of ovarian origin. Next Generation Sequencing (NGS) showed ATRX and NF2 copy number losses. Fluorescence in situ hybridization (FISH) for EWSR1 demonstrated monosomy of 22q in greater than 90% of cells. These molecular alterations have not been previously reported in ovarian or extra-CNS ependymomas.