The sections show a surface-based, triphasic lesion composed of disorganized cartilage, irregular bone, and a proliferative spindle-cell stroma. The cartilaginous component is hypercellular, containing haphazardly arranged chondrocytes with mild nuclear enlargement and occasional binucleated forms. Blue bone matrix is noted characterized by a smudgy, basophilic mineralized appearance is present at the interface of ossification. The bony trabeculae are irregular and lack the organized lamellar structure or hematopoietic marrow characteristic of a mature osteochondroma. The intervening spindle-cell stroma is cellular but lacks significant cytological atypia or atypical mitotic figures. No evidence of malignancy in submitted material.
Index mass.
None fragments collectively measured 1.5x1x0.6 cm, totally embedded.
Index mass, excision: