Nests and cords of epithelial cells set in fibrous stroma
Epitheliod cells with eosinophilic cytoplasm and desmosomes; ovoid nuclei with mild pleomorphism and inconspicuous mitotic activity
Intervening stroma composed of spindle cells with a loose fascicular pattern; cytoplasm is eosinophilic; nuclei are ovoid and monomorphic with inconspicuous mitotic activity
IHC: keratin (AE1/AE3), p40
Soft tissue extension
Nests and cords of epithelial cells set in fibrous stroma
Squamoid epithelial cells with eosinophilic cytoplasm and desmosomes; ovoid nuclei with mild pleomorphism and inconspicuous mitotic activity
Intervening stroma composed of spindle cells with a storiform pattern; cytoplasm is eosinophilic; nuclei are ovoid and monomorphic with inconspicuous mitotic activity
Peripheral irregular bone trabeculae with conspicuous osteoblastic rimming
Inconspicuous tubules and individual epithelial cells set in fibrous stroma
Epithelial cells with scant eosinophilic cytoplasm; bland ovoid nuclei with inconspicuous mitotic activity
Prominent stroma composed of spindle cells with a storiform pattern; cytoplasm is eosinophilic; nuclei are ovoid and monomorphic with inconspicuous mitotic activity
Interspersed irregular bone trabeculae with conspicuous osteoblastic rimming
IHC: keratin (AE1/AE3)
Epithelial cells may be difficult to appreciate without the benefit of immunohistochemistry for keratin or p63
Inconspicuous tubules and individual epithelial cells set in fibrous stroma
Epithelial cells with scant eosinophilic cytoplasm; bland ovoid nuclei with inconspicuous mitotic activity
Prominent stroma composed of spindle cells with a storiform pattern; cytoplasm is eosinophilic; nuclei are ovoid and monomorphic with inconspicuous mitotic activity
Interspersed irregular bone trabeculae with conspicuous osteoblastic rimming
IHC: keratin (AE1/AE3), p63
Epithelial cells may be difficult to appreciate without the benefit of immunohistochemistry for keratin or p63