Emperipolesis

Emperipolesis is an intact cell within another cell. The term is derived from em (inside), peri (around), and polemai (is wander about).

Emperipolesis in Rosai-Dorfman disease. H&E stain.

General

• Nonspecific finding seen in a number of conditions.

It is seen in:

• Rosai-Dorfman disease.
• Megakaryocytes.
• Autoimmune hepatitis.

Microscopic

Features:

• Intact cell (e.g. lymphocyte, neutrophil) within a macrophage.
  • Engulfed cell usually has a halo around it.

DDx:

• Cell overlap.
• Hemophagocytosis.

Images

• 

  Emperipolesis in Rosai-Dorfman disease. S100 immunostain.

• 

  Megakaryocyte containing a neutrophil. May-Grünwald Giemsa stain.

See also

• Hemophagocytic syndrome.