Osteochondroma

Bone stalk with cartilaginous cap that, in turn, is covered by thin perichondrium

Cartilage cap is thin and hypocellular; irregular columns of chondrocytes; eosinophilic cytoplasm; round-ovoid nuclei with small nucleoli, occasional binucleation, mild pleomorphism, and inconspicuous mitotic activity; abundant hyaline cartilage matrix

Perichondrium is continuous with the periosteum; spindle-stellate fibroblasts; eosinophilic cytoplasm with delicate tapering processes; monomorphic ovoid nuclei with inconspicuous mitotic activity; collagenous stroma

Bone stalk is continuous with underlying bone marrow; anastomosing trabeculae with fatty marrow spaces

Bone stalk with cartilaginous cap that, in turn, is covered by thin perichondrium

Cartilage cap is thin and hypocellular; irregular columns of chondrocytes; eosinophilic cytoplasm; round-ovoid nuclei with small nucleoli, occasional binucleation, mild pleomorphism, and inconspicuous mitotic activity; abundant hyaline cartilage matrix

Perichondrium is continuous with the periosteum; spindle-stellate fibroblasts; eosinophilic cytoplasm with delicate tapering processes; monomorphic ovoid nuclei with inconspicuous mitotic activity; collagenous stroma

Bone stalk is continuous with underlying bone marrow; anastomosing trabeculae with fatty marrow spaces

Bone stalk with cartilaginous cap that, in turn, is covered by thin perichondrium

Cartilage cap is thin and hypocellular; irregular columns of chondrocytes; eosinophilic cytoplasm; round-ovoid nuclei with small nucleoli, occasional binucleation, mild pleomorphism, and inconspicuous mitotic activity; abundant hyaline cartilage matrix

Perichondrium is continuous with the periosteum; spindle-stellate fibroblasts; eosinophilic cytoplasm with delicate tapering processes; monomorphic ovoid nuclei with inconspicuous mitotic activity; collagenous stroma

Bone stalk is continuous with underlying bone marrow; anastomosing trabeculae with fatty marrow spaces

Bone stalk with cartilaginous cap that, in turn, is covered by thin perichondrium

Cartilage cap is thin and hypocellular; irregular columns of chondrocytes; eosinophilic cytoplasm; round-ovoid nuclei with small nucleoli, occasional binucleation, mild pleomorphism, and inconspicuous mitotic activity; abundant hyaline cartilage matrix

Perichondrium is continuous with the periosteum; spindle-stellate fibroblasts; eosinophilic cytoplasm with delicate tapering processes; monomorphic ovoid nuclei with inconspicuous mitotic activity; collagenous stroma

Bone stalk is continuous with underlying bone marrow; anastomosing trabeculae with fatty marrow spaces

Bone stalk with cartilaginous cap that, in turn, is covered by thin perichondrium

Cartilage cap is thin and hypocellular; irregular columns of chondrocytes; eosinophilic cytoplasm; round-ovoid nuclei with small nucleoli, occasional binucleation, mild pleomorphism, and inconspicuous mitotic activity; abundant hyaline cartilage matrix

Perichondrium is continuous with the periosteum; spindle-stellate fibroblasts; eosinophilic cytoplasm with delicate tapering processes; monomorphic ovoid nuclei with inconspicuous mitotic activity; collagenous stroma

Bone stalk is continuous with underlying bone marrow; anastomosing trabeculae with fatty marrow spaces