There are no reliable early symptoms of appendiceal cancer, which, in part, explains why the majority

of these patients are diagnosed incidentally during surgical exploration or late when peritoneal or

systemic dissemination has already occurred. The rarity of appendiceal neoplasms makes screening

programs unrealistic, and they are found by colonoscopy in <10% of cases.108

The treatment of appendiceal neoplasms depends upon type, stage, and medical comorbidities; not all

appendiceal tumors demand the same therapy, operative or otherwise. Interestingly, appendiceal

adenocarcinomas are associated with secondary tumors in up to 35% of patients, most often involving

other areas of the GI tract.109

Mucoceles

Mucoceles of the appendix refer to a distended mucin-filled organ, which can be due to either benign

(cystadenoma) or malignant (cystadenocarcioma) disease (Fig. 71-4). Such mucoceles are due to an

obstructed appendiceal lumen, leading to a large mucin-filled structure, often with calcification in the

wall. Such lesions can be readily diagnosed by CT scans, and are often incidental findings. A simple

appendectomy is curative for benign cystadenomas. Resection should be done with great care so as not

to rupture the lesion, which can lead to dissemination. With rupture, whether of a histologically benign

or even more commonly with a malignant cystadenocarcinoma, peritoneal tumor implantation can

occur, leading to mucinous ascites, and a condition known as pseudomyxoma peritonei (PMP, see

below). The presence of epithelial cells in the mucin extruded from the mucocele at the time of rupture

greatly increases the likelihood of recurrence. Due to the potential for malignancy, and possible

sequellae of rupture (spontaneous or iatrogenic), appendectomy should be performed in otherwise

healthy patients.

Appendiceal Adenocarcinoma

Appendiceal adenocarcinoma typically presents either with symptoms suggestive of appendicitis or

symptoms related to peritoneal dissemination. CT or MRI imaging is preferred and PET imaging is of

little value in these cases.110–113 Appendiceal adenocarcinoma represents an unusual neoplasm, which

has several variants. Mucinous appendiceal carcinoma is the most common, with colonic type or the

signet-ring variant being less common, and associated with poorer outcomes.114 Appendiceal carcinomas

are now more common than carcinoid (neuroendocrine) tumors. The appendiceal carcinomas are further

subdivided into low- and high-grade lesions.115,116 Low-grade lesions (sometimes also known as

disseminated peritoneal mucinous tumors) have more than double the long-term survival rate of highgrade lesions. Signet-ring cells are associated with a poorer prognosis. For known high-grade

appendiceal carcinoma without peritoneal or distant metastasis, a right colectomy is appropriate

surgical therapy. Those found to have nodal metastases should be considered for systemic

chemotherapy, with regimens used for colon carcinoma.

Figure 71-4. A: Mucocele. B: Mucocele (opened).

In patients with appendiceal carcinoma, peritoneal dissemination is frequently found at presentation

(50% of high-grade and 20% of low-grade lesions),114 and begins with tumor-induced obstruction of the

appendiceal lumen. The obstruction in the face of continued mucin production eventually leads to

perforation, and subsequent dissemination of mucous-producing epithelial cells throughout the

peritoneal cavity. The pattern of spread is clearly related to the grade of disease. Low-grade mucin1900

producing lesions are associated with implantation, and spread along the peritoneal surfaces with

distant or lymphatic metastases in less than 10% of cases. A typical pattern of peritoneal disseminations

begins in the right lower quadrant of the abdomen followed by the pelvis, right upper quadrant, then

diffusely throughout the peritoneal spaces. This is distinguished from high-grade lesions, which have

more substantial risks of nodal and systemic metastasis, resulting in poorer prognosis. In addition,

approximately 7% of the low-grade lesions have lymph-node involvement, and another 16% will

dedifferentiate into higher-grade lesions during the course of the disease.117,118

The rarity of the disease has unique implications in diagnosis, classification, terminology, and

treatment. Therefore, several misconceptions are still prevalent among clinicians. First, due to the fact

that the majority of PMP cases occur in association with appendiceal primaries the term

“pseudomyxoma peritonei” has been used as synonym with the variant of appendiceal-induced

peritoneal surface disease associated with excessive production of mucin. Although most PMP is indeed

from appendiceal neoplasms, the term is descriptive and can be applied to any primary (including

ovarian, colon, or even pancreatic mucinous) cancer that has the ability to produce mucinous ascites.119

Consequently, the term PMP would be better used as a clinical sign rather as a distinct disease. Second,

not all mucinous appendiceal tumors are associated with long-term survival. Factors such as histologic

grade, tumor biology of the primary lesion,120 age, functional status of the patient, and extent of disease

at the time of diagnosis determine the prognosis of these patients. Third, not every appendiceal primary

is associated with mucin production or ascites. Many patients present with peritoneal disease that has no

phenotypic difference from any other gastrointestinal malignancy with peritoneal dissemination (Fig.

71-5).

10 The management of patients with peritoneal surface disease from appendiceal neoplasms is still a

matter of debate. These patients have been traditionally treated with debulking procedures or systemic

chemotherapy alone.119,121,122 Right colectomy does not seem to convey a survival advantage in patients

with peritoneal dissemination.123 Though low-grade appendiceal tumors treated with limited debulking

procedures can provide some patients with prolonged survival, more than 90% of these patients will

inevitably develop local recurrence and death from bowel obstruction.121 To deal with the problem of

postdebulking residual microscopic disease, a variety of “adjuvant” therapies have been evaluated.

Intraperitoneal photodynamic therapy, radiation (with 32P), and chemotherapy instillation have been

tried and largely abandoned. In 1980, hyperthermic intraperitoneal perfusion was described by

Spratt.123 Sugarbaker subsequently published his early experience in combining cytoreduction with

heated intraperitoneal chemotherapy.124,125 This combined approach of aggressive cytoreduction

combined with HIPEC has since been more thoroughly evaluated at many centers.126 HIPEC is now

considered a standard of care in the treatment of peritoneal dissemination from appendiceal cancer (Fig.

71-6).

Figure 71-5. Mucinous appendiceal neoplasm with pseudomyxoma peritonei.

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