CASE 1239 Published on 21.11.2001

Pseudomyxoma peritonei

Section

Genital (female) imaging

Case Type

Clinical Cases

Authors

Vikramaditya Prabhudesai, SJ Tebby, MA Siddiqui

Patient

21 years, female

Categories
No Area of Interest ; Imaging Technique Ultrasound, CT, MR
Clinical History
The patient first presented with abdominal distention and was diagnosed with mucinous cystadenocarcinoma of the right ovary.
Imaging Findings
The patient first presented with abdominal distention and was diagnosed with mucinous cystadenocarcinoma of the right ovary. A laparotomy and right oophorectomy were performed. She subsequently had a debulking procedure, followed by chemotherapy. A third laparotomy six years later was again followed by chemotherapy. She then developed a recto-vaginal fistula, which was stented. She has had ultrasound, CT scan and MRI. There is persistent intraperitoneal disease, although she looks quite well. It has been decided to manage her non-operatively.
Discussion
Pseudomyxoma peritonei is a poorly understood condition characterised by mucinous implants involving the peritoneum. Underlying cellular growth may be either benign or malignant, but the condition is usually progressive. Pseudomyxoma peritonei is a clinical entity where there is gelatinous ascites. It is secondary to a benign or malignant tumour of the appendix, ovary or other organs (pancreas, colon, etc). Histologically there is a spectrum of features. This includes peritoneal lesions composed of abundant extracellular mucin to focally proliferative mucinous epithelium with mild atypia to lesions composed of more abundant epithelium with features of carcinoma. Extraperitoneal involvement is rare, but has been described (retroperitoneal).

Sonographic findings include irregularly dispersed echodense masses which show no acoustic shadowing; they may also have an echogenic wall with an anechoic interior. These masses adhere to the bowels and abdominal wall and float with change in patient position. Calcification has also been described in pseudomyxoma peritonei, secondary to ovarian papillary mucinous cystadenocarcinoma. The ultrasound appearance may differ in benign and malignant disease. Septation probably represents margins of the mucinous implants.

CT is distinctive in that the gelatinous nature of the deposit produces a mantle of low-density material over the surface of the liver causing scalloping of its margins, in association with the cystic peritoneal collection. Walls may show some calcification. The pressure of the material prevents bowel loops floating up, which may help to differentiate from ascites.

On MRI the gelatinous material coats the peritoneal surface and causes scalloping similar to that seen on CT scan. Septae are more easily seen. There is enhancement, which helps differentiate from ascites. The multiplanar capability of MRI will demonstrate the extent of the disease.

Differential Diagnosis List
Pseudomyxoma peritonei
Final Diagnosis
Pseudomyxoma peritonei
Case information
URL: https://www.eurorad.org/case/1239
DOI: 10.1594/EURORAD/CASE.1239
ISSN: 1563-4086