Presentation
Abdominal pain and swelling.
Patient Data
Right large retroperitoneal complex cystic mass lesion is seen extending from the right hypochondrial region/hepatorenal pouch extends down into the right paracolic gutter retro-colic in location and reaches the right side of the pelvis. The lesion appears complex predominantly cystic showing enhancing internal septations which show tiny calcifications. The lesion is abutting the adjacent liver and right kidney. It invades the right psoas muscle. The lesion encases the patent right iliac vessels. In the pelvis, it compresses and displaces the urinary bladder to the left side. It also encases and compresses the right ureter with consequent marked right hydrouretronephrosis.
Gallbladder stones.
Radiological findings were suggestive of primary retroperitoneal tumor, such as myxoid liposarcoma or primary mucinous adenocarcinoma.
CT guided biopsy showed low grade mucinous tumor.
The patient underwent surgical excision of the mass as well as cholecystectomy, hysterectomy, and bilateral salpingo-oophorectomy. Histopathology after excision confirmed the low-grade mucinous neoplasm. Immunophenotyping showed positivity for CK20 and CDX2 with negativity for CK7 suggesting appendicular origin. However, the surgeon denied any relationship of the lesion with the appendix or the ovaries and presumed primary retroperitoneal mucinous neoplasm. The patient subsequently was treated by chemotherapy.
Case Discussion
Primary retroperitnoeal mucinous tumors are rare tumors and have a wide range of differential diagnosis.
Hypothesis for retroperitoneal mucinous neoplasm development include:
- teratoma with predominant mucinous epithelial cells
- heterotopic ovarian tissue
- invagination of the peritoneal tissue into the retroperitoneum which undergo metaplasia
- intestinal duplication
Three types of primary retroperitoneal mucinous neoplam
- mucinous cystadenoma
- mucinous borderline tumors of low malignant potential
- mucinous cystadenocarcinoma
The differential diagnosis for other cystic retroperitoneal lesions include:
- retroperitoneal lymphatic malformation
- retroperitoneal mucinous cystadenoma
- retroperitoneal cystic teratoma
- retroperitoenal cystic mesothelioma
- pseudomyxoma retroperitonei with cystic change
- perianal mucinous carcinoma with cystic change
- pseudocysts
- pancreatic pseudocyst
- non-pancreatic pseudocyst
- retroperitoneal lymphocele
- urinoma
Unable to process the form. Check for errors and try again.