DQ stain: Medium power
Hypercellular smear with predominantly single cells
DQ stain: High power
Hypercellular smear with small nests and singly dispersed large polygonal cells with prominent nucleoli and vacuolated cytoplasm
Pap stain: Low power
Hypercellular smear with small nests and singly dispersed cells with epithelioid and spindled morphology
Pap stain: Medium power
Large epithelioid cells with enlarged irregular nuclei, prominent nucleoli and granular to vacuolated cytoplasm
DQ stain: High power
Large epithelioid cells with enlarged irregular nuclei, prominent nucleoli and granular to vacuolated cytoplasm
Pap stain: High power
Note rare mitotic figure
Pap stain: High power
Large epithelioid cells with enlarged irregular nuclei, prominent nucleoli and granular to vacuolated cytoplasm
Cell block: H&E stain
Large epithelioid tumor cells seen within the cell block section
Features
• Commonly affects distal extremities
• Ages 20-40
• Female predilection
• Also called melanoma of soft parts
• Cellular smears
• Biphasic with epithelioid and spindle cells
• Nested fascicular architectural pattern
• Single cells and clusters
• Polygonal to spindle cells
• Granular to clear cytoplasm
• Intranuclear cytoplasmic inclusions
• May have melanin rarely
• Nuclei may be pleomorphic
• Multinucleation with wreath-like nuclei
• Vesicular chromatin
• Prominent nucleoli
• Tigroid background may be seen
• Mitosis and necrosis rare
• IHC: positive for S100, HMB45, Mart1; negative for cytokeratin
• Molecular: t(12;22) EWS/ATF-1
• Zeppa P et al. Diagn Cytopathol. 1999 Dec;21(6):405-8.
• Cardillo M et al. Cancer. 2001 Aug 25;93(4):246-51.