Pathology: dedifferentiated liposarcoma

Liposarcoma, "low-grade" dedifferentiation

  • Hypocellular; spindle-stellate cells arranged in loose fascicles

  • Dense eosinophilic cytoplasm

  • Ovoid and hyperchromatic nuclei with moderate pleomorphism; inconspicuous mitotic activity

  • Scattered epithelioid cells, some with multinucleation

  • Abundant fibrillary collagenous stroma; low power fields lacking adipocytes

  • IHC: MDM2

  • FISH: MDM2 amplified

Liposarcoma, "low-grade" dedifferentiation

  • Hypocellular; spindle-stellate cells arranged in loose fascicles

  • Dense eosinophilic cytoplasm

  • Ovoid and hyperchromatic nuclei with moderate pleomorphism; inconspicuous mitotic activity

  • Scattered epithelioid cells, some with multinucleation

  • Abundant fibrillary collagenous stroma; low power fields lacking adipocytes

  • IHC: MDM2

  • FISH: MDM2 amplified

Liposarcoma, "low-grade" dedifferentiation

  • Hypocellular; spindle-stellate cells arranged in loose fascicles

  • Dense eosinophilic cytoplasm

  • Ovoid and hyperchromatic nuclei with moderate pleomorphism; inconspicuous mitotic activity

  • Abundant fibrillary collagenous stroma; low power fields lacking adipocytes

  • FISH: MDM2 amplified

Dedifferentiated liposarcoma

  • Moderately cellular; spindle-polygonal cells with patternless distribution

  • Dense eosinophilic cytoplasm with occasional clear vacuoles

  • Ovoid and hyperchromatic nuclei with moderate pleomorphism and frequent multinucleation; rare mitotic activity

  • Prominent collagenous-myxoid stroma

  • IHC: MDM2

  • FISH: MDM2 amplified

Dedifferentiated liposarcoma, undifferentiated pleomorphic sarcoma (UPS)-like

  • Cellular; spindle-polygonal cells with vague storiform pattern

  • Dense eosinophilic cytoplasm with occasional clear vacuoles

  • Ovoid and hyperchromatic nuclei with moderate pleomorphism and occasional multinucleation; conspicuous mitotic activity

  • IHC: MDM2, CDK4

  • FISH: MDM2 amplified

Dedifferentiated liposarcoma, undifferentiated pleomorphic sarcoma (UPS)-like

  • Cellular; spindle-polygonal cells with vague storiform pattern

  • Dense eosinophilic cytoplasm with occasional clear vacuoles

  • Ovoid and hyperchromatic nuclei with moderate pleomorphism and occasional multinucleation; mitotic activity

  • Prominent lymphoplasmacytic inflammatory infiltrate

  • IHC: MDM2, CDK4

  • FISH: MDM2 amplified

Dedifferentiated liposarcoma, undifferentiated pleomorphic sarcoma (UPS)-like

  • Cellular; spindle-polygonal cells with vague storiform pattern

  • Dense eosinophilic cytoplasm with occasional clear vacuoles

  • Ovoid and hyperchromatic nuclei with moderate pleomorphism and occasional multinucleation; mitotic activity

  • IHC: MDM2

  • FISH: MDM2 amplified

Dedifferentiated liposarcoma, myxofibrosarcoma-like

  • Hypocellular; spindle-polygonal cells with patternless distribution

  • Dense eosinophilic cytoplasm with occasional clear vacuoles

  • Ovoid and hyperchromatic nuclei with moderate pleomorphism and frequent multinucleation; mitotic activity

  • Prominent myxoid stroma with arcing thin-walled vasculature

  • FISH: MDM2 amplified

  • PMID: 15832195

Dedifferentiated liposarcoma, with meningothelial-like whorls and metaplastic bone formation

  • Variable cellularity; spindle-stellate cells arranged in loose fascicles punctuated by whorls-storiform patterns

  • Eosinophilic cytoplasm with long tapering processes

  • Ovoid nuclei with vesicular chromatin, small nucleoli and mild pleomorphism; inconspicuous mitotic activity

  • Scattered epithelioid cells, some with multinucleation and moderate pleomorphism

  • Abundant collagenous stroma; metaplastic bone; background of well-differentiated liposarcoma

  • FISH: MDM2 amplified

  • PMID: 21317707

Dedifferentiated liposarcoma, with meningothelial-like whorls and metaplastic bone formation

  • Variable cellularity; spindle-stellate cells arranged in loose fascicles punctuated by whorls-storiform patterns

  • Eosinophilic cytoplasm with long tapering processes

  • Ovoid nuclei with mild pleomorphism; inconspicuous mitotic activity

  • Scattered epithelioid cells, some with multinucleation and marked pleomorphism

  • Abundant collagenous stroma; calcified nodules

  • Mild chronic inflammatory infiltrate

  • FISH: MDM2 amplified

  • PMID: 21317707

Dedifferentiated liposarcoma, with heterologous rhabdomyoblastic differentiation

  • Cellular; spindle cell fascicles with clusters of polygonal cells

  • Spindle cells have scant eosinophilic cytoplasm and occasional clear vacuoles; ovoid and hyperchromatic nuclei with moderate pleomorphism; mitotic activity

  • Polygonal cells have abundant eosinophilic cytoplasm; eccentric nuclei

  • IHC: desmin, myogenin, MDM2

  • FISH: MDM2 amplified

Dedifferentiated liposarcoma, with heterologous leiomyosarcomatous differentiation

  • Cellular spindle cell fascicles arising in well-differentiated background

  • Eosinophilic cytoplasm with fibrillary processes and occasional clear vacuoles

  • Ovoid and elongated nuclei with mild pleomorphism; mitotic activity

  • IHC: H-caldesmon, MDM2

  • FISH: MDM2 amplified

  • PMID: 7943536

Dedifferentiated liposarcoma, with heterologous osteosarcomatous differentiation

  • Spindle-polygonal cells arranged in sheets

  • Eosinophilic-amphophilic cytoplasm with occasional vacuoles

  • Ovoid and hyperchromatic nuclei with moderate pleomorphism and occasional multinucleation; mitotic activity

  • Areas of chondroid and osteoid matrix

  • Mild chronic inflammatory infiltrate

  • FISH: MDM2 amplified

  • PMID: 7943536

Dedifferentiated liposarcoma, with epithelioid features

  • Sheets of epithelioid-spindle cells

  • Abundant amphophilic cytoplasm

  • Central-eccentric round-ovoid nuclei with macronucleoli and moderate pleomorphism; brisk mitotic activity

  • Mild acute and chronic inflammatory infiltrate

  • IHC: MDM2, CDK4

  • FISH: MDM2 amplified

  • PMID: 28719466

Dedifferentiated liposarcoma, with "homologous" lipoblastic (pleomorphic liposarcoma-like) differentiation

  • Sheets of adipocytes admixed with spindle-epithelioid cells

  • Clear-eosinophilic cytoplasm

  • Round-ovoid, hyperchromatic, and pleomorphic nuclei; inconspicuous mitotic activity

  • Interspersed pleomorphic lipoblasts; necrosis

  • FISH: MDM2 amplified

  • PMID: 20588177