Page 615 - Robbins Basic Pathology by Vinay Kumar, Abul K. Abbas, Jon C. Aster
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Tumors of the Appendix 601
tumor, or mass of worms. Ischemic injury and stasis of S U M M A RY
luminal contents, which favor bacterial proliferation, trigger Appendix
inflammatory responses including tissue edema and neutro-
philic infiltration of the lumen, muscular wall, and periappen- • Acute appendicitis is most common in children and adoles-
diceal soft tissues. cents. It is thought to be initiated by increased intraluminal
pressure consequent to obstruction of the appendiceal
MORPHOLOGY lumen, which compromises venous outflow.
In early acute appendicitis, subserosal vessels are congested, • The most common tumor of the appendix is the
and a modest perivascular neutrophilic infiltrate is present carcinoid.
within all layers of the wall. The inflammatory reaction trans-
forms the normal glistening serosa into a dull, granular- • The clinical presentation with appendiceal adenocarcinoma
appearing, erythematous surface. Although mucosal can be indistinguishable from that with acute
neutrophils and focal superficial ulceration often are present, appendicitis.
these findings are not specific, and diagnosis of acute appen-
dicitis requires neutrophilic infiltration of the muscularis BIBLIOGRAPHY
propria. In more severe cases, focal abscesses may form ORAL CAVITY
within the wall (acute suppurative appendicitis), and
these may even progress to large areas of hemorrhagic ulcer- Hennessey PT, Westra WH, Califano JA: Human papillomavirus and
ation and gangrenous necrosis that extend to the serosa, head and neck squamous cell carcinoma: recent evidence and clini-
creating acute gangrenous appendicitis, which often is cal implications. J Dent Res 88:300, 2009. [Discussion of head and neck
followed by rupture and suppurative peritonitis. cancers associated with HPV.]
Clinical Features Leemans CR, Braakhuis BJ, Brakenhoff RH: The molecular biology of
Typically, early acute appendicitis produces periumbilical head and neck cancer. Nat Rev Cancer 11:9, 2011. [An up to date
pain that ultimately localizes to the right lower quadrant, discussion of the molecular biology of head and neck cancer.]
followed by nausea, vomiting, low-grade fever, and a
mildly elevated peripheral white cell count. A classic phys- Leivo I: Insights into a complex group of neoplastic disease: advances
ical finding is McBurney’s sign, deep tenderness noted at a in histopathologic classification and molecular pathology of sali-
location two thirds of the distance from the umbilicus to vary gland cancer. Acta Oncol 45:662, 2006. [A good review of the
the right anterior superior iliac spine (McBurney’s point). histologic spectrum of salivary gland tumors.]
These signs and symptoms often are absent, however, cre-
ating difficulty in clinical diagnosis. ESOPHAGUS
Liacouras CA, Furuta GT, Hirano I, et al: Eosinophilic esophagitis:
TUMORS OF THE APPENDIX
updated consensus recommendations for children and adults. J
The most common tumor of the appendix is the carcinoid. Allergy Clin Immunol 128:3, 2011. [The most current diagnostic defini-
It usually is discovered incidentally at the time of surgery tion of and therapeutic recommendations for eosinophilic esophagitis.]
or on examination of a resected appendix. This neoplasm Sharma P: Clinical practice. Barrett’s esophagus. N Engl J Med
most frequently involves the distal tip of the appendix, 361:2548, 2009. [A comprehensive discussion of Barrett esophagus.]
where it produces a solid bulbous swelling up to 2 to 3 cm
in diameter. Although intramural and transmural exten- INFLAMMATORY DISEASE OF THE STOMACH
sion may be evident, nodal metastases are very infrequent, Malfertheiner P, Chan FK, McColl KE: Peptic ulcer disease. Lancet
and distant spread is exceptionally rare. Conventional ade-
nomas or non–mucin-producing adenocarcinomas also occur in 374:1449, 2009. [Summary of current understanding of peptic ulcer
the appendix and may cause obstruction and enlargement disease.]
that mimics the changes of acute appendicitis. Mucocele, a Mills JC, Shivdasani RA: Gastric epithelial stem cells. Gastroenterol-
dilated appendix filled with mucin, may simply stem from ogy 140:412, 2011. [A good discussion of cell lineages and differentiation
an obstructed appendix containing inspissated mucin or pathways in the gastric epithelium.]
may be a consequence of mucinous cystadenoma or mucinous Polk DB, Peek RM, Jr: Helicobacter pylori: gastric cancer and beyond.
cystadenocarcinoma. In the latter instance, invasion through Nat Rev Cancer 10:403, 2010. [A good review of H. pylori and mecha-
the appendiceal wall can lead to intraperitoneal seeding nisms by which it is linked to gastric cancer.]
and spread. In women, the resulting peritoneal implants
may be mistaken for mucinous ovarian tumors. In the most NEOPLASTIC DISEASE OF THE STOMACH
advanced cases, the abdomen fills with tenacious, semi- Murphy G, Pfeiffer R, Camargo MC, Rabkin CS: Meta-analysis shows
solid mucin, a condition called pseudomyxoma peritonei. This
disseminated intraperitoneal disease may be held in check that prevalence of Epstein-Barr virus-positive gastric cancer differs
for years by repeated debulking but in most instances is based on sex and anatomic location. Gastroenterology 137:824, 2009.
ultimately fatal. [A meta-analysis of over 15,000 gastric cancer cases tested for EBV RNA.]
Polk DB, Peek RM Jr: Helicobacter pylori: gastric cancer and beyond.
Nat Rev Cancer 10:403, 2010. [A good review of H. pylori and mecha-
nisms by which it is linked to gastric cancer.]
Sagaert X, Van Cutsem E, De Hertogh G, et al: Gastric MALT lym-
phoma: a model of chronic inflammation-induced tumor develop-
ment. Nat Rev Gastroenterol Hepatol 7:336, 2010. [A discussion of
gastric MALT lymphoma pathogenesis.]
INTESTINAL OBSTRUCTION
Kapur RP: Practical pathology and genetics of Hirschsprung’s disease.
Semin Pediatr Surg 18:212, 2009. [A review of Hirschsprung disease
etiology and diagnosis.]
