Peritoneal metastatic colorectal malignancy

A 3 cm segment of distal sigmoid colon is circumferentially thickened (up to 8 mm) with narrowing of the bowel lumen which remains patent. Extending superiorly from the bowel wall at this point there are lobulated, centrally hypodense masses ( 5.2 x 2.6 cm ) with a further mass more laterally ( 2.6 x 3.5 cm ) adjacent to the left external iliac vessels and left ovary. The more proximal sigmoid colon is diffusely thick walled as is a loop of ileum running through the pelvis. There is no evidence of bowel obstruction. A small amount of free fluid is present in the pelvis.

There is extensive omental caking and numerous peritoneal soft tissue deposits. The liver is encased in mildly hypodense material without definite scalloping.

Lobulated soft tissue (2.2 x 1.7 cm) extends laterally to the right from the head of the pancreas. It is not clear if this represents a further deposit or a primary pancreatic lesion.

Within segment VII of the liver there is a subtle ill defined 4.5 x 3.1 x 3.7 cm hypodense mass.

The gallbladder, spleen and adrenals are unremarkable. A 12 mm round hypodense lesion in the mid pole of the left kidney likely represents a simple cyst but is too small to definitively characterize. No free intraperitoneal gas.

The lung bases are clear. No destructive osseous lesion.

Conclusion

• Extensive omental disease with a likely colorectal primary of the sigmoid colon. DDx of metastatic sigmoid infiltration secondary to an ovarian or pancreatic primary.
• A subtle hypodense lesion in segment VII of the liver is concerning for further metastatic disease.
• No bowel obstruction.