Chondroblastoma

Sheets of polygonal cells

Amphophilic cytoplasm

Ovoid-reniform nuclei with lobulation, occasional grooves and small nucleoli; inconspicuous mitotic activity

Focal hyaline cartilage matrix with pericellular calcification; interspersed osteoclast-type giant cells

IHC: S100, D240

Sheets of polygonal cells

Eosinophilic cytoplasm

Ovoid-reniform nuclei with lobulation, occasional grooves and small nucleoli; inconspicuous mitotic activity

Focal hyaline cartilage matrix; secondary aneurysmal cyst formation; interspersed osteoclast-type giant cells

IHC: DOG1

PMID: 22335248

Sheets of polygonal cells

Eosinophilic cytoplasm

Ovoid-reniform nuclei with lobulation and occasional grooves; inconspicuous mitotic activity

Focal hyaline cartilage matrix; interspersed osteoclast-type giant cells; secondary aneurysmal cyst formation and haemosiderin deposition

IHC: D2-40