Dedifferentiated chondrosarcoma

Dedifferentiated chondrosarcoma

• Loose fascicles of polygonal-spindle cells juxtaposed with conventional low-intermediate grade chondrosarcoma

• Eosinophilic cytoplasm

• Ovoid nuclei macronucleoli and marked pleomorphism; conspicuous mitotic activity 

• Collagenous stroma with mild chronic inflammation

Dedifferentiated chondrosarcoma

• Sheets of polygonal cells juxtaposed with low-intermediate grade chondrosarcoma

• Pale amphophilic cytoplasm

• Round-ovoid nuclei with moderate pleomorphism and small nucleoli; conspicuous mitotic activity

• Occasional interspersed foci of osteoblastic differentiation

Dedifferentiated chondrosarcoma

• Sheets of polygonal-spindle cells juxtaposed with low-intermediate grade chondrosarcoma

• Amphophilic cytoplasm

• Round-ovoid nuclei with moderate pleomorphism and small nucleoli; conspicuous mitotic activity

• Variable collagenous stroma; conspicuous necrosis

Dedifferentiated chondrosarcoma

• Sheets of polygonal cells

• Pale amphophilic cytoplasm

• Round-ovoid nuclei with moderate pleomorphism and small nucleoli; conspicuous mitotic activity

• Occasional delicate bands of osteoid

Chondroid matrix was apparent on imaging, and confirmed on subsequent resection

Dedifferentiated chondrosarcoma

• Spindle-polygonal cells with storiform-fascicular pattern

• Pale amphophilic cytoplasm

• Round-ovoid nuclei with moderate pleomorphism and small nucleoli; conspicuous mitotic activity

• Areas of chondroid differentiation with variable cellularity

• Areas of osteoblastic differentiation, seams of osteoid with variable mineralization, and osteoclast-like multinucleated giant cells

Dedifferentiated chondrosarcoma

• Infiltrative; moderately cellular lobules of stellate-polygonal cells

• Pale eosinophilic cytoplasm

• Raisinoid hyperchromatic nuclei with mild pleomorphism; mitotic activity

• Abundant hyaline cartilage matrix; areas of myxoid degeneration;

• Areas of osteoblastic differentiation; seams of osteoid with variable mineralization