Summary: A 58-year-old female presents with abdominal distension. Her past
medical history is significant for hysterectomy ten years ago, reason
unknown. Physical examination was positive for ascites. Laboratory
findings included an elevated CEA level (carcinogen embryonic antigen).
Radiology workup included an ultrasound initially and then a computed
tomography (CT ) of the abdomen and pelvis.
Pseudomyxoma peritonei secondary to mucocele of the appendix
A contrast-enhanced CT scan of the abdomen and pelvis showed a
markedly distended abdomen with complex fluid. Additionally, there is a
tubular fluid filled structure adjacent to a loop of colon (Figure 1).
transabdominal ultrasound reveals a complex mass surrounding the
bladder and throughout the lower quadrants consistent with pseudomyxoma
peritonei Figures 2 and 3).
Exploratory laparotomy revealed
gelatinous-like substance throughout the abdomen and pelvis.
Additionally, a tumor in the appendix diagnosed as adenocarcinoma of the
Mucocele of the appendix is defined as a distension of the appendix
with mucous occurring in approximately 2% of the population. The
etiologies include obstruction by a fecalith or tumor, adhesions,
endometriosis or volvulus. Mucinous cystadenoma and cystadenocarcinoma
comprise most of the cases.
The clinical presentation is variable.
50% of cases present with a palpable mass. On ultrasound, the mass can
vary in echogenicity from anechoic to hyperechoic. The origin of the
mass may be confusing. The differential diagnosis for an appendiceal
mucocele in the right lower quadrant includes mesentric duplication
cyst, mesenteric cyst, right ovarian cyst, and right hydrosalpinx.
can be very helpful in locating and evaluating the extent of disease.
Extra-appendiceal spread of disease such as ascites and peritoneal
implants are usually signs of malignancy. Pseudomyxoma peritonei is
rare, but when present, patients may have abdominal pain with fullness
or discomfort. This may result from spillage of mucin causing a foreign
body reaction or spread of malignant mucocele. The prognosis for
peritoneal disease associated with mucinous adenocarcinoma is poor.
A cystic tumor of the ovary may be mistaken for an appendiceal mucocele and vice versa.
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- Krebs TL, Daly BD, Wong-You-Cheong JJ, Grumbach K. General case of the day: Mucinous cystadenocarcinoma of the appendix. Radiographics. 1998;18:1049–1050.
- Skaane P, Ruud TE, Haffner J. Ultrasonographic features of mucocele of the appendix. J Clin Ultrasound. 1988;16:584–587.