Diagnostic Ultrasound - Abdomen and Pelvis

Peritoneal Carcinomatosis
Diagnoses: Abdominal Wall/Peritoneal Cavity
TERMINOLOGY
• Peritoneal spread of tumor from epithelial malignancy
resulting in peritoneal thickening, omental infiltration,
serosal implants, and ascites
IMAGING
• Implants develop where peritoneal fluid collects: Dome of
liver, omentum, paracolic gutters, and pelvic recesses
• Omental involvement may be nodular or diffuse, producing
an omental cake
• Peritoneal masses may be solid, cystic, or mixed, depending
on primary neoplasm
• Hypoechoic rind-like thickening of peritoneum
• Ascites: Complex with septations or internal echoes (jiggle
with transducer pressure)
• Dissemination of tumor also occurs via hematogenous,
contiguous, or lymphatic spread
KEY FACTS
• Diagnosis may be obtained by US-guided aspiration of
peritoneal fluid or fine-needle/core biopsy of omental
cake/peritoneal masses
• Color Doppler confirms that omental/peritoneal deposits
are solid; improves biopsy yield when viable tumor is
targeted
TOP DIFFERENTIAL DIAGNOSES
• Pseudomyxoma peritonei
• Peritoneal mesothelioma
• Peritoneal tuberculosis
• Peritoneal sarcomatosis
• Peritoneal lymphomatosis
CLINICAL ISSUES
• Present with abdominal distension and pain, weight loss,
malaise, fever
• May have elevated tumor markers such as CA125 or CEA
• Prognosis variable depending on primary tumor, but
generally poor prognosis
(Left) Longitudinal ultrasound
of the midline anterior
abdominal wall in a patient
with metastatic pancreatic
neuroendocrine carcinoma
shows there are 2 peritoneal
soft tissue implants growing
through the anterior
abdominal wall ſt with
adjacent ascites st and bowel
. (Right) Longitudinal
ultrasound of the right upper
quadrant inferior to the liver
shows ascites st and a thick
lobular omental cake ſt from
pancreatic carcinomatosis.
(Left) Transverse color
Doppler ultrasound of the
midline anterior abdominal
wall in a patient with ovarian
carcinomatosis and an
omental cake ſt. Color flow
is present within the
omentum. A small amount of
ascites st is noted. (Right)
Transverse ultrasound of the
right upper quadrant shows
complex septated ascites ſt
anterior to the liver st,
representing mucinous
carcinomatosis from
appendiceal carcinoma.
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