Primary chondroblastic osteosarcoma with glandular areas - An extremely rare case of divergent differentiation

Abstract

Malignant bone tumors with epithelial differentiation are extremely rare. A primary carcinosarcoma arising in bone is characterised by the presence of both epithelial and mesenchymal differentiation. Herein we report an extremely rare case of primary chondroblastic osteosarcoma with true divergent glandular differentiation in a twenty-nine year old female. Microscopic sections reveal a high-grade chondroblastic osteogenic sarcoma with definite areas showing neoplastic osteoid formation and nests, cords and acinar (glandular) structures with cytokeratin positivity suggesting definitive epithelial glandular differentiation. Our case illustrates the ability of osteosarcomas to show epithelial differentiation characterized both by cytokeratin expression and differentiation to adenocarcinomatous cells displaying distinct glandular differentiation