Peritoneal Carcinomatosis
Peritoneal carcinomatosis (dissemination of metastatic disease throughout portions of the peritoneal cavity) is most commonly associated with ovarian, pancreatic and GI malignancies.
When the CT images demonstrate multiple soft tissue lesions and the PET images show them to be FDG-avid, the diagnosis is readily apparent and made with confidence.
Occasionally, however, evidence of carcinomatosis is present on the PET images before visible lesions can be clearly identified on the non-contrast CT images.
Diagnosing and reporting peritoneal carcinomatosis solely from the PET images — without CT confirmation of the findings — can be unnerving, but is expected of the PET/CT radiologist.
Diagnosing carcinomatosis solely from the PET images requires a strong familiarity the typical sites of involvement:
- Serosal surfaces of liver & spleen
- Omentum (small nodules to omental caking)
- Paracolic gutters
- Peritoneal reflections
- Mesentery
- Serosal surfaces of the bowel
On rare occasion, non-Hodgkin lymphoma patients can present with peritoneal lymphomatosis, which appears exactly like carcinomatosis.
