Bone and soft tissue sarcomas in cerebrospinal fluid and effusion: A 20-year review at our institution.

The incidence of BSTS in fluid cytology is extremely rare, and it can have cytologic features similar to those of non-BSTS malignancies. Although, in most cases, a comparison with a prior known BSTS specimen may suffice, the use of ancillary studies is extremely helpful in arriving at the correct diagnosis. However, in cases with no known prior malignancy, including BSTS in the differential diagnosis is prudent for preventing misdiagnosis.