Peritoneal Metastases

R. Brooke Jeffrey, MD

Key Facts

Terminology

Peritoneal carcinomatosis, peritoneal implants, omental masses (“caking”)
Metastatic disease to omentum, peritoneal surface, peritoneal ligaments, &/or mesentery

Imaging

Best diagnostic clue: Omental caking, soft tissue implants on peritoneal surface
CT findings
- Ascites, nodular peritoneal thickening/enhancement, hypovascular omental caking
- Spiculated mesentery
- Evidence of bowel obstruction with delineation of transition zone from dilated to nondilated bowel
Best imaging tool: CECT or MR
Protocol advice: Oral & IV contrast (CECT), gadolinium-enhanced GRE or T1 sequence (MR)

Top Differential Diagnoses

Pathology

Clinical Issues

Diagnostic Checklist

(Left) Axial anatomic rendering of peritoneal metastases. Note the anterior omental cake

and serosal implants

. (Right) Axial CECT shows a massive, malignant ascites due to peritoneal metastases

. Note the metastases to the abdominal wall, lymph nodes, and perirenal space bilaterally

(Left) Axial CECT shows classic widespread metastases from melanoma into the gastric wall

and lymph nodes

. (Right) Axial CECT in the same patient demonstrates the spread of metastases to the small bowel

, lymph nodes

, and omentum. Both nodular and diffuse metastases are seen

TERMINOLOGY

Synonyms

Definitions

Metastatic disease to omentum, peritoneal surface, peritoneal ligaments, &/or mesentery

IMAGING

General Features

Best diagnostic clue
- Omental caking, soft tissue implants on peritoneal surface
- Cystic peritoneal masses with ovarian carcinoma on peritoneal surfaces
- Ascites, mesenteric stranding, bowel obstruction
Location
- Peritoneum, mesentery, peritoneal ligaments
Size
- Variable; 5 mm nodules to large confluent omental caking
Morphology
- Nodular, plaque-like, or large omental mass