Pathology: epithelioid haemangioendothelioma

Epithelioid haemangioendothelioma, conventional

  • Nests-cords of epithelioid cells

  • Pale eosinophilic cytoplasm with occasional vacuoles

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

  • Occasional myxohyaline stroma; necrosis

  • IHC: ERG

  • RNA-seq: WWTR1::CAMTA1 gene fusion

Epithelioid haemangioendothelioma, conventional

  • Fascicles of epithelioid cells

  • Pale eosinophilic cytoplasm with occasional vacuoles containing amorphous debris

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

  • Occasional myxohyaline stroma; incomplete rim of metaplastic bone*

  • IHC: ERG

  • RNA-seq: WWTR1::CAMTA1 gene fusion

* Calcification is a rare event in these tumours

Epithelioid haemangioendothelioma, conventional

  • Nests-cords of epithelioid cells

  • Pale eosinophilic cytoplasm with rare vacuoles

  • Ovoid nuclei with small nucleoli, occasional multinucleation and moderate pleomorphism;* inconspicuous mitotic activity

  • Occasional myxohyaline stroma

  • IHC: CD34, ERG

  • RNA-seq: WWTR1::CAMTA1 gene fusion

* This tumour exhibits an atypical degree of pleomorphism

Epithelioid haemangioendothelioma, conventional

  • Spindle-stellate-round cells in nests and cords

  • Pale eosinophilic cytoplasm with occasional vacuoles

  • Round-ovoid hyperchromatic nuclei with mild pleomorphism; inconspicuous mitotic activity

  • Abundant myxohyaline stroma

  • IHC: ERG

  • RNA-seq: WWTR1::CAMTA1 gene fusion

Epithelioid haemangioendothelioma, conventional

  • Nests-fascicles of epithelioid cells

  • Pale eosinophilic cytoplasm with occasional vacuoles containing amorphous debris

  • Ovoid nuclei with small nucleoli, occasional pseudonuclear inclusions and mild pleomorphism; inconspicuous mitotic activity

  • Occasional myxohyaline stroma; peripheral lymphoid aggregates

  • IHC: ERG

  • RNA-seq: WWTR1::CAMTA1 gene fusion

  • PMID: 33125182

Epithelioid haemangioendothelioma, TFE3-rearranged

  • Circumscribed; sheets-nests of epithelioid cells

  • Pale eosinophilic cytoplasm,with occasional vacuoles containing amorphous debris

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

  • Occasional myxohyaline stroma; lipomatous background

  • IHC: ERG, TFE3

  • RNA-seq: YAP1::TFE3 gene fusion

  • PMID: 34381186

Epithelioid haemangioendothelioma, TFE3-rearranged

  • Nests of epithelioid-polygonal cells

  • Pale amphophilic cytoplasm

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

  • Intervening fibrous stroma

  • IHC: TFE3

  • FISH: YAP1::TFE3 gene fusion

  • PMID: 23737213