Giant cell tumor of bone presenting in the lumbar spine of a 35-year-old female: cytodiagnosis and other diagnostic considerations.

Fine-needle aspiration (FNA) is commonly used in the evaluation of both primary and metastatic bone lesions. Giant cell tumor (GCT) of bone is one of the primary bone neoplasms that can be diagnosed with good success on FNA as its cytologic features are relatively reproducible. However, this entity classically involves the ends (or epiphyses) of the longs bones making an FNA diagnosis of a GCT of bone in other anatomic locations is challenging and requires the consideration of a differential diagnosis. By invoking clinico-radiographical correlation and maximizing our specimen, we were able to diagnose a GCT of bone involving the L1 vertebral body in a 35-year-old female.