Fascicles of spindle cells
Eosinophilic cytoplasm with occasional perinuclear vacuoles
Ovoid and elongated nuclei with mild pleomorphism; conspicuous mitotic activity
IHC: H-caldesmon
Fascicles of spindle cells
Eosinophilic cytoplasm
Ovoid and elongated nuclei with scattered pleomorphism; conspicuous mitotic activity
Interspersed osteoclast-like giant cells
Necrosis
IHC: desmin, smooth muscle actin
PMID: 1703914
Fascicles of spindle cells
Eosinophilic cytoplasm with occasional perinuclear vacuoles
Ovoid and elongated nuclei with minimal atypia; occasional mitotic activity
IHC: H-caldesmon
Fascicles of spindle cells
Eosinophilic cytoplasm with occasional perinuclear vacuoles
Ovoid and elongated nuclei with minimal atypia; occasional mitotic activity
Necrosis
IHC: H-caldesmon
NB: cremaster muscle origin
Fascicles of spindle cells
Eosinophilic cytoplasm with occasional perinuclear vacuoles
Ovoid and elongated nuclei with scattered pleomorphism; conspicuous mitotic activity
Fascicles of spindle cells
Eosinophilic cytoplasm with occasional perinuclear vacuoles
Ovoid and elongated nuclei with scattered pleomorphism; conspicuous mitotic activity
IHC: H-caldesmon
NB: vascular wall origin
Fascicles of spindle cells
Eosinophilic cytoplasm with occasional perinuclear vacuoles
Ovoid and elongated nuclei with scattered pleomorphism; conspicuous mitotic activity
IHC: H-caldesmon
Fascicles of spindle cells
Eosinophilic cytoplasm with occasional perinuclear vacuoles
Ovoid and elongated nuclei with moderate pleomorphism; conspicuous mitotic activity
IHC: H-caldesmon, keratin (AE1/AE3)*
* Aberrant keratin is common in leiomyosarcoma (PMID: 1716444)
Vague fascicles of spindle cells
Eosinophilic cytoplasm with occasional perinuclear vacuoles
Ovoid nuclei with moderate pleomorphism; conspicuous mitotic activity
Necrosis
IHC: H-caldesmon
Spindle cell fascicles
Eosinophilic cytoplasm with occasional perinuclear vacuoles
Ovoid nuclei with moderate pleomorphism; conspicuous mitotic activity
Origin from thick-walled vessel
IHC: H-caldesmon
Circumscribed; vague fascicles of spindle cells
Eosinophilic cytoplasm with occasional perinuclear vacuoles
Ovoid nuclei with marked pleomorphism; conspicuous mitotic activity
IHC: H-caldesmon
Circumscribed; spindle cell fascicles
Eosinophilic cytoplasm with long tapering processes
Ovoid nuclei with mild-moderate pleomorphism; occasional mitotic activity
IHC: H-caldesmon
Circumscribed; vague fascicles of spindle cells
Amphophilic cytoplasm with long tapering processes
Ovoid nuclei with marked pleomorphism; conspicuous mitotic activity
Mild lymphocytic infiltrate
IHC: H-caldesmon
Fascicles of spindle cells
Eosinophilic cytoplasm with occasional perinuclear vacuoles
Ovoid, hyperchromatic and elongated nuclei with moderate pleomorphism; conspicuous mitotic activity
IHC: H-caldesmon
Fascicles of spindle cells
Eosinophilic cytoplasm with occasional perinuclear vacuoles
Ovoid and elongated nuclei with marked pleomorphism; brisk mitotic activity
Areas resembling undifferentiated pleomorphic sarcoma, and pleomorphic liposarcoma
IHC: H-caldesmon
FISH: negative for MDM2 amplification
NB: inferior vena cava origin
Spindle cell fascicles juxtaposed with sheets of polygonal cells
Spindle cells have eosinophilic cytoplasm; ovoid and elongated nuclei with minimal atypia
Polygonal cells have eosinophilic-amphophilic cytoplasm; round-ovoid nuclei with marked pleomorphism; brisk mitotic activity
IHC: H-caldesmon
PMID: 22175893
Note loss of immunoreactivity in area of dedifferentiation