Pseudomyxoma peritonei (PMP) is a rare condition
consisting of mucinous ascites, most commonly arising
from mucinous tumours of the appendix and occasionally
from the ovary. Very rarely, mucinous deposits arise in the
retroperitoneum without intraperitoneal involvement. This
has been termed pseudomyxoma extraperitonei (PME). Our
48-year-old female patient presented with PME mimicking
a psoas abscess for which retroperitoneal exploration and
biopsy was done with accidental breach of the peritoneum.
She declined further surgery and re-presented 4 years later
with disseminated PMP. She underwent debulking surgery
including right oophorectomy which was confirmed as the
primary tumour source.