Table 1.

Histologic guide for differentiating LCPC and SCPC.

Feature	LCPC	SCPC
Cellular morphology	Large cells with abundant cytoplasm Large nests, sheets and cords with peripheral palisading Geographic necrosis	Small cells with a high nuclear: cytoplasmic ratio Significant crush artifact Apoptosis and necrosis
Tumor nuclei	Coarse, clumpy chromatin	Nuclear molding
Nucleoli	Prominent	Absent
Mitotic rate	High (Ki-67 >60%)	High (Ki-67 >60%)
Requirements for diagnosis	Specific morphologic features and strong IHC for ≥1 NE marker	Wider spectrum of suggestive cytologic features without specific IHC requirements
IHC	Typically negative staining or only focal positivity for luminal markers (PSA, PSAP)	Typically negative staining or only focal positivity for luminal markers (PSA, PSAP)