Omentum

The omentum is a much neglected structure. It is often removed in the context of gynecologic oncology procedure.

Normal omentum

Microscopic

Features:

• Fibroadipose tissue covered by mesothelium.

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OMENTUM, OMENTECOMY: 
- FIBROADIPOSE TISSUE COVERED BY MESOTHELIUM -- CONSISTENT WITH OMENTUM. 
- NEGATIVE FOR MALIGNANCY.

Radiology

• "Omental cake" refers to a thickened omentum.
  • The finding is non-specific - etiologies:
    • Metastatic tumours: stomach, ovary and colon.
    • Infection: tuberculous peritonitis.

Grossing

• There is no widely accepted evidence-based standard; thus, the protocol differs from centre to centre.
  • In the context of a gynecologic malignancy/suspected gynecologic malignancy:
    • It is reasonable to put through six (standard) blocks if there is no gross evidence of disease.
    • One study suggests 3-5 blocks is enough if there is no macroscopic disease, and one block enough if there is macroscopic disease.

Pathology of the omentum

Benign

Mesothelial:

• Benign multicystic mesothelioma.
• Adenomatoid tumour.
• Solitary fibrous tumour.

Other:

• Peritoneal inclusion cyst.
• Endometriosis.
• Endosalpingiosis.
• Omental hernia.

Malignant

Primary:

• Malignant mesothelioma.
• Primary peritoneal serous carcinoma.
• Serous tumour of low malignant potential.
• Sarcoma.
• Other Muellerian tumours. (???)

Metastatic:

• Serous carcinoma of the ovary.

See also

• Gynecologic pathology.
• Peritoneum.