Spindle-stellate cells with loose fascicular-storiform pattern
Amphophilic cytoplasm
Ovoid nuclei with small nucleoli and mild atypia; inconspicuous mitotic activity
Prominent osteoclast-like multinucleated giant cells; occasional areas of interstitial haemorrhage and siderophages; trabeculae of woven bone
IHC: H3F3A H34W, keratin (AE1/AE3)
DNA-seq: GNAS mutation (c.601C>T; p.Arg201Cys)
Fibro-osseous proliferation; spindle-stellate cells
Eosinophilic cytoplasm
Monomorphic ovoid nuclei; inconspicuous mitotic activity
Interspersed between collagenous stroma; irregular-shaped woven bone trabeculae with incomplete osteoblastic rimming
Fibro-osseous proliferation; spindle-stellate cells
Eosinophilic cytoplasm
Monomorphic ovoid nuclei; inconspicuous mitotic activity
Interspersed between cells there is collagenous stroma; irregularly-shaped woven bone trabeculae with incomplete osteoblastic rimming; occasional osteoclast-type giant cells
Fibro-osseous proliferation; spindle-stellate cells
Eosinophilic cytoplasm
Monomorphic ovoid nuclei; inconspicuous mitotic activity
Interspersed between cells there is collagenous stroma; irregularly-shaped woven bone trabeculae with incomplete osteoblastic rimming; occasional osteoclast-type giant cells
Fibro-osseous proliferation; spindle-stellate cells
Eosinophilic cytoplasm
Monomorphic ovoid nuclei; inconspicuous mitotic activity
Interspersed between cells there is collagenous stroma; irregularly-shaped woven bone trabeculae with incomplete osteoblastic rimming; occasional osteoclast-type giant cells
Fibro-osseous proliferation; spindle-stellate cells
Eosinophilic cytoplasm
Monomorphic ovoid nuclei; inconspicuous mitotic activity
Interspersed between cells there is collagenous stroma; irregularly-shaped woven bone trabeculae with incomplete osteoblastic rimming; occasional osteoclast-type giant cells
Fibro-osseous proliferation; spindle-stellate cells
Eosinophilic cytoplasm
Monomorphic ovoid nuclei; inconspicuous mitotic activity
Interspersed between cells there is collagenous stroma; irregularly-shaped woven bone trabeculae with incomplete osteoblastic rimming; occasional osteoclast-type giant cells
Fibro-osseous proliferation; spindle-stellate cells
Eosinophilic cytoplasm
Monomorphic ovoid nuclei; inconspicuous mitotic activity
Interspersed between cells there is collagenous stroma; irregularly-shaped woven bone trabeculae with incomplete osteoblastic rimming; occasional osteoclast-type giant cells
Fibro-osseous proliferation; spindle-stellate cells
Eosinophilic cytoplasm
Monomorphic ovoid nuclei; inconspicuous mitotic activity
Irregularly-shaped woven bone trabeculae with incomplete osteoblastic rimming; occasional foamy macrophages
IHC: SATB2