Pseudomyxoma peritonei due to ruptured appendiceal mucocele

Clinical History

45-year-old man was admitted to our hospital due to acute subfebril abdominal diffuse pain with a history of chronic inferior right quadrant abdominal pain and abdominal distension. An abdominal enhanced CT was performed.

Imaging Findings

The abdominal CT scan revealed multiple irregular, fluid-filled structures that partially compressed the cecum associated to a peritoneal gelatinous ascites creating impressions on the hepatic surface.

Discussion

Pseudomyxoma peritonei (PMP), a syndrome first described by Karl F. Rokitansky in 1842, is an enigmatic fatal disease characterised by dissecting gelatinous ascites and multifocal peritoneal epithelial implants secreting copious globules of extra-cellular mucin. The most common cause is a ruptured mucinous tumour of the appendix called appendiceal mucocoele. Sometimes , mucinous tumours of the colon, rectum, stomach, pancreas and urachal tumours can be implicated [1].

PMP may be divided into two pathological sub-types which have etiological and prognostic significance:
*peritoneal adenomucinosis: a peritoneal neoplasm composed largely of mucin associated with fibrosis with minimal cytologic atypia and mitoses. Primary tumour is generally an adenoma.
*peritoneal mucinous carcinoma: characterised by proliferative epithelium, glands, nests, or individual cells with marked cytologic atypia. Primary tumour is a mucinous adenocarcinoma [2].

PMP symptoms may appear to be subtle, and therefore, may initially be misdiagnosed. It may include pain in the lower right quadrant, abdominal distension, digestive disturbances such as constipation and/or diarrhoea, the "appearance" of a "hernia", or other vague or acute symptoms.

History, examination, and imaging studies often lead to the diagnosis.
A typical imaging ultrasound finding is echogenic peritoneal masses or ascites with echogenic particles which (unlike other forms of particulate ascites such as haemoperitoneum or pus in the peritoneum) do not move, and may show scalloping of the liver, spleen and at times other organs.
Computed tomography (CT) is the modality of choice because it allows relatively accurate localisation and quantification of PMP. Enhanced CT shows cystic masses in the expected region of the appendix associated to dissecting peritoneal ascites with scalloping of visceral surfaces, particularly the liver and omental thickening[3].

Fibrosis and adhesions cause recurrent bowel obstructions.
Treatment is surgical debulking, followed by infusion of intraperitoneal chemotherapy. The evolution is often progressively fatal [1, 3]. A peritonectomy was performed in our patient, but couldn't be optimal because of the tumour diffusion. The alterated general condition of the patient, especially in the post-operative course, made him ineligible for an intra-peritoneal chemotherapy.

Pseudomyxoma peritonei is a rare disease characterised by a complete redistribution of mucin within the peritoneal cavity. History, examination, and imaging studies often lead to the diagnosis. Treatment is surgical debulking, followed by infusion of intraperitoneal chemotherapy but the evolution is often fatal.

Differential Diagnosis List

Final Diagnosis

Pseudomyxoma peritonei due to ruptured appendiceal mucocele

URL:	https://eurorad.org/case/10742
DOI:	10.1594/EURORAD/CASE.10742
ISSN:	1563-4086