Endometrial Dating

Proliferative:

• Straight, tubular glands
• Regular, tall, pseudostratified columnar epithelium
• Numerous mitotic figures
• Epithelium can look atypical
• Stroma has thickly compacted spindle cells with scant cytoplasm
• Abundant stromal mitoses

Early Secretory:

• Basal secretory vacuoles
• No mitoses

Mid-Late Secretory:

• Secretions in gland lumens
• Glands initially dilated, then tortuous with serated appearance
• Spiral arterioles
• Stromal edema initially
• Later, predecidual change with cytoplasmic eosinophilia
• Starts around spiral arterioles
• Develops mostly in upper 2/3rds

Menstrual:

• Diffuse decidualized change
• Stromal inflammation, neutrophils
• Fibrin in stroma (“pink balls”)
• Cracks in stroma
• Condensation of stroma (“blue balls”) (note: may be seen in any phase of the cycle)