Low power: Pap stain
Note high cellularity
Papillary fragments, acinar groups and single cells
Medium power: Pap stain
Variable branching of papillary structures
Note fibrovascular cores
High power: Pap stain
Papillary fragment with myxoid change of fibrovascular core
Note uniformity of cells
High power: Pap stain
Uniform cells of various shapes
Abundant foamy cytoplasm
Note single cells in background (one of which has round, other reniform nucleus)
High power: Pap stain
Acinar arrangement of cells
Note variable nuclear shapes from round to oval to reniform
Also note frothy cytoplasm
High power: Pap stain
Acinar arrangement and single cells
Note cytoplasmic vacuoles and long tails
Also note oval to reniform nuclei
High power: Pap stain
Predominantly single cells
Note various cell shapes from round to spindle and cercariform
Note rare cells with binucleation
High power: Pap stain
Cercariform cells with long tails
Note pale chromatin and delicate nuclear grooves
High power: Pap stain
Predominantly single cells
Note irregular nuclei and occasional binucleation
High power: Pap stain
Acinar arrangement and single cells
Cercariform cells
Punched out cytoplasmic vacuoles
Irregular nuclei and pale chromatin
Features
• Moderate to high cellularity
• Variably branching papillary groups
• Myxoid change in fibrovascular cores
• Scattered single cells
• Occasional acinar groups
• Plasmacytoid cells
• Cercariform cells (tadpole like cells)
• Spindled cells
• Fine to large punched out vacuoles
• Variable nuclear morphology
• Round to oval nuclei
• Reniform nuclei
• Rare binucleation
• Occasionally irregular nuclei
• Pale chromatin
• Delicate nuclear grooves
• Rare hyaline globules
• Cholesterol clefts
• Rare necrotic debris
• Express alpha1-antitrypsin, beta-catenin (nuclear), CD10, vimentin; cytokeratin, NSE, CD56, progesterone receptor +/- ; usually negative for chromogranin, estrogen receptor, CA19-9, S100, CD99
Samad A. et al. Cancer Cytopathol. 2013 Jun;121(6):298-310