Sheets and nests of epithelioid-spindle cells
Pale eosinophilic cytoplasm with occasional clearing
Ovoid nuclei with marked pleomorphism; conspicuous mitotic activity
Scant collagenous stroma
IHC: desmin, SOX10, p53
DNA-seq: NF1 exon 28; c.3755T>A (p.Leu1252*) mutation identified
Biphasic; fascicles of spindle cells and gland-forming epithelial cells
Eosinophilic cytoplasm with occasional intracytoplasmic mucin
Ovoid-round nuclei with vesicular chromatin; conspicuous mitotic activity
Collagenous stroma
Fascicles of spindle cells
Pale amphophilic cytoplasm
Ovoid nuclei with small nucleoli; conspicuous mitotic activity
Interspersed adipocytes and metaplastic bone
Underlying NF1
Multinodular with "marbled" pattern (variable cellularity)
Spindle-epithelioid cells with pale amphophilic cytoplasm
Ovoid-round nuclei with moderate pleomorphism; conspicuous mitotic activity
Scant myxoid stroma
IHC: H3K27me3
Underlying NF1
"Marbled" pattern (variable cellularity)
Spindle-epithelioid cells with pale amphophilic cytoplasm
Ovoid-round nuclei with moderate pleomorphism; conspicuous mitotic activity
Intervening collagenous-myxoid stroma
IHC: S100
Underlying NF2
Fascicles of spindle-epithelioid cells
Eosinophilic cytoplasm
Round nuclei with small nucleoli and moderate pleomorphism; occasional mitotic activity
NB: background conventional schwannoma
Underlying rhabdoid tumour syndrome
Sheets of epithelioid cells
Amphophilic cytoplasm
Round nuclei with small nucleoli and moderate pleomorphism; conspicuous mitotic activity
IHC: S100, SOX10
Spindle-polygonal cells with amphophilic cytoplasm
Ovoid-round nuclei with mild pleomorphism; occasional mitotic activity
Interspersed rhabdomyoblastic cells with abundant eosinophilic cytoplasm; eccentric nuclei with occasional multinucleation
Abundant myxoid stroma
Underlying NF1
Peritheliomatous pattern
Spindle-polygonal cells with amphophilic cytoplasm
Ovoid-round nuclei with marked pleomorphism; conspicuous mitotic activity
Small clusters of rhabdoid cells with abundant eosinophilic cytoplasm; eccentric nuclei with occasional multinucleation
Abundant myxoid stroma
IHC: myogenin, H3K27me3
Fascicles of spindle cells with pale amphophilic cytoplasm
Ovoid-round nuclei with moderate pleomorphism; conspicuous mitotic activity
Interspersed nests of rhabdoid cells with abundant eosinophilic cytoplasm; eccentric round nuclei with macronucleoli
IHC: myogenin, H3K27me3
Short fascicles of spindle cells
Pale amphophilic cytoplasm
Ovoid-round nuclei with coarse chromatin and moderate pleomorphism; conspicuous mitotic activity
Epithelioid cells centred around vessels; patchy necrosis
IHC: desmin, myogenin, H3K27me3
Sheets and nests of epithelioid cells; amphophilic cytoplasm with occasional eosinophilic globules
Round-ovoid nuclei with speckled chromatin and mild-moderate pleomorphism; occasional mitotic activity
Areas of prominent neurofibrillary background
IHC: H3K27me3
PMID: 34339532
Biphasic with spindle cell and chondroid components
Spindle cells: herringbone pattern; pale amphophilic cytoplasm; ovoid nuclei with mild-moderate pleomorphism; conspicuous mitotic activity
Cartilage: hypo-moderately cellular lobules of stellate-polygonal cells; pale eosinophilic cytoplasm; round hyperchromatic nuclei with mild pleomorphism; rare mitotic activity; abundant hyaline cartilage matrix with myxoid degeneration
IHC: H3K27me3, S100, SOX10
RNA-seq: negative
ISBN: 978-1-933477-30-5