Features

Architecture

• Moderate cellularity
• Loosely cohesive clusters
• Occasional single cells
• Rare groups with small vessels

Cellular features

• Prominent acinar formation
• Uniform polarized cells (Plasmacytoid)
• Abundant apical cytoplasm
• Pale foamy to eosinophilic granular cytoplasm

Nuclear features

• Basal nuclear location
• Round nuclear configuration
• Rare binucleated cells
• Single prominent nucleolus
• Clumped chromatin
• Lack of atypia

Background

• Numerous nuclei devoid of cytoplasm (naked nuclei)
• Occasional cases with hyaline globules
• Rare to absent mitoses
• Rare to absent necrosis

Ancillary studies

• Express cytokeratin, CK8, CK18, zymogen granules PAS positive; negative for CK7, CK19, CK20

Reference

Sigel CS et al. Cancer Cytopathol. 2013 Aug;121(8):459-70.
Stelow EB et al. Diagn Cytopathol. 2006 May;34(5):367-72.