Pathology: giant cell fibroblastoma

Giant cell fibroblastoma

  • Infiltrative; hypocellular; spindle cells with loose fascicular-storiform pattern

  • Amphophilic cytoplasm

  • Monomorphic ovoid nuclei; rare mitotic activity

  • Abundant collagenous stroma; scattered polygonal cells with multinucleation

  • IHC: CD34

  • RNA-seq: COL1A1::PDGFB gene fusion

Giant cell fibroblastoma

  • Infiltrative; hypocellular; spindle-stellate cells with loose fascicular-storiform pattern

  • Amphophilic cytoplasm

  • Monomorphic ovoid nuclei; rare mitotic activity

  • Abundant collagenous stroma; scattered polygonal cells with multinucleation

  • RNA-seq: COL1A1::PDGFB gene fusion