The patient went on to have surgery.

Histology

MICROSCOPIC DESCRIPTION: Sections show a hypocellular cartilaginous tumor composed of sheets and lobules of chondroid matrix containing small chondrocytes. Occasional binucleate forms are present. Foci of necrotic cartilage are present. No cellular atypia or mitoses are seen. Cartilage is closely associated with mature bony trabeculae, however no permeation or destructive bone invasion is seen.

Multiple fragments of bone partly replaced by a chondroid proliferation with hilar matrix and paucicellular and bland appearing chondrocytes. However in areas the chondroid proliferation extends between pre-existing bony trabeculae and the occasional large irregular nucleus is noted.

FINAL DIAGNOSIS: Low grade chondroid tumor with features of low grade chondrosarcoma.