Peritoneal inclusion cyst

Peritoneal inclusion cyst is a relatively uncommon benign pathology of the peritoneum.

It is also known as benign multicystic mesothelioma; it should not be confused with malignant mesothelioma and benign papillary mesothelioma.

It may referred to as inflammatory cyst of the peritoneum or mesothelial inclusion cyst.^{[citation needed]}

Multilocular peritoneal inclusion cyst redirect here.

General

• Usually conservative management.
• Serum CA-125 usually low.
• May occur in men.

Gross

Features:

• Multilocular thin-walled cysts containing serous fluid +/- blood.
  • Occasionally unilocular.
• May be up to 15 cm.
• Can be adherent to the ovary.

Microscopic

Features:

• Thin-walled, irregular-shaped, cysts - unicystic or multicystic.
  • Mesothelial lining +/- squamous metaplasia.
  • Eosinophilic fluid.

DDx:

• Ovarian serous borderline tumour.
• Ovarian serous carcinoma.
• Primary peritoneal serous carcinoma.
• Primary peritoneal malignant mesothelioma.

Images:

• Multicystic mesothelioma (rsna.org).
• Benign multicystic peritoneal mesothelioma (nih.gov).

IHC

Features:

• Calretinin +ve.
• WT-1 +ve.

See also

• Peritoneum.