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12. A pathologist is reviewing slides of a resected colon cancer specimen. The cancer was noted to invade through
the bowel wall into the subserosa. There was one involved
lymph node. Assuming there was no distant metastatic
disease noted on preoperative imaging, what is the correct tumor-node-metastasis (TNM) classification and
stage?
A. T3N1M0, stage II
B. T4N1M0, stage II
C. T3N1M0, stage III
D. T4N1M0, stage III
must be a first-degree relative of one of the others) in two
successive generations of a family with one patient diagnosed
before age 50 years. The presence of other related carcinomas should raise the suspicion of this syndrome. Revised criteria Amsterdam II requires three or more relatives with an
HNPCC-related malignancy in which at least one is a firstdegree relative of the others, two generations are affected, at
least one cancer occurred before age 50, familial adenomatous polyposis (FAP) has been excluded, and pathology of the
tumors has been reviewed and confirmed. In a patient with
an established diagnosis of colorectal cancer, tumor testing
for presence of mismatch repair gene products (immunohistochemistry) and/or MSI can sometimes serve as screening
for this syndrome. (See Schwartz 11th ed., pp. 1292–1293.)
Answer: C
Staging. Colorectal cancer staging is based on tumor depth
and the presence or absence of nodal or distant metastases.
Older staging systems, such as the Dukes’ Classification and
its Astler-Coller modification, have been replaced by the TNM
staging system described by the American Joint Committee
on Cancer (AJCC). The AJCC TNM classification has recently
been updated to reflect survival outcomes based upon the
Surveillance Epidemiology and End Results (SEER) registry.
Stage I disease includes adenocarcinomas that are invasive
through the muscularis mucosa but are confined to the submucosa (T1) or the muscularis propria (T2) in the absence
of nodal metastases. Stage II disease consists of tumors that
invade through the bowel wall into the subserosa or nonperitonealized pericolic or perirectal tissues (T3) or into
other organs or tissues or through the visceral peritoneum
(T4) without nodal metastases. Stage III disease includes any
T stage with nodal metastases, and stage IV disease denotes
distant metastases. (See Schwartz 11th ed., p. 1296.)
13. How can the role of adjuvant chemotherapy following
resection of colon cancer be most accurately described?
A. Adjuvant chemotherapy should be used after all
colon cancer resections to reduce the risk of recurrence and improve overall survival.
B. Adjuvant chemotherapy has the best evidence for
routine use in those with positive lymph nodes.
C. Microsatellite instable (MSI)-high patients do not
respond to adjuvant chemotherapy and therefore
should not be offered it.
D. As long as lymph nodes are negative, patients
with stage II disease do not benefit from adjuvant
chemotherapy.
Answer: B
Stages I and II: Localized colon carcinoma (T1-3, N0, M0).
The majority of patients with stages I and II colon cancer will
be cured with surgical resection. Few patients with completely
resected stage I disease will develop either local or distant
recurrence, and adjuvant chemotherapy does not improve
survival in these patients. However, up to 46% of patients
with completely resected stage II disease will ultimately die
from colon cancer. For this reason, adjuvant chemotherapy
has been suggested for selected patients with stage II disease
(young patients, tumors with “high-risk” histologic findings).
It remains controversial as to whether chemotherapy improves
survival rates in these patients. In some cases, molecular profiling may predict prognosis, although it is important to note
that these tools have not been shown to predict response to
therapy. At present, molecular profiling for selecting patients
to receive chemotherapy remains unproven.
Stage III: Lymph node metastasis (Tany, N1, M0). Patients
with lymph node involvement are at significant risk for both
local and distant recurrence, and adjuvant chemotherapy has
been recommended routinely in these patients. 5- Fluorouracil–
based regimens (with leucovorin) and oxaliplatin (FOLFOX)
reduce recurrences and improve survival in this patient population. It is important to note, however, that a subgroup of
14. Which of the following statements about total mesorec-
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tal excision (TME) for rectal cancer is TRUE?
A. TME improves local recurrence but not long-term
survival.
B. TME is not necessary for rectosigmoid tumors.
C. TME is associated with less blood loss than a blunt
dissection.
D. TME carries a higher risk of injury to the pelvic
nerves than a blunt dissection.
patients with stage III disease will do well without chemotherapy. MSI status in particular predicts good prognosis.
Subset analysis from the CRYSTAL trial has shown that
patients with MSI-high stage III disease do not benefit from
5-fluorouracil–based chemotherapy. Molecular profiling,
therefore, may be helpful in determining which stage III
patients can safely avoid systemic chemotherapy. (See Schwartz
11th ed., pp. 1298–1299.)
Answer: C
Total mesorectal excision (TME) is a technique that uses sharp
dissection along anatomic planes to ensure complete resection
of the rectal mesentery during low and extended low anterior
resections. For upper rectal or rectosigmoid resections, a partial
mesorectal excision of at least 5 cm distal to the tumor appears
adequate. TME both decreases local recurrence rates and
improves long-term survival rates. Moreover, this technique is
associated with less blood loss and less risk to the pelvic nerves
and presacral plexus than is blunt dissection. The principles of
TME should be applied to all radical resections for rectal cancer. (See Schwartz 11th ed., p. 1300.)
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15. You encounter an unfamiliar-appearing mass when performing a colonoscopy. Your attending, who is standing
next to you, surmises that this is a leiomyoma of the colon
and asks how you plan to manage it. How do you respond?
A. If the lesion is small and asymptomatic, it should be
left alone.
B. The lesion should be excised only if it is >5 cm due to
the risk of malignancy at this size.
C. All leiomyomas should be resected because malig-
nancy (leiomyosarcoma) cannot be ruled out.
D. Oncologic (radical) resections are always indicated
for leiomyoma, regardless of size, due to the high
likelihood of malignancy.
16. Gastrointestinal stromal tumors (GISTs) are, by definition, malignant.
A. True
B. False
Answer: C
Leiomyoma and leiomyosarcoma. Leiomyomas are benign
tumors of the smooth muscle of the bowel wall and occur most
commonly in the upper gastrointestinal tract. Most patients
are asymptomatic, and lesions are often diagnosed incidentally
when a mass is seen on endoscopy or felt on digital rectal examination. However, large lesions can cause bleeding or obstruction.
Because it is difficult to differentiate a benign leiomyoma from
a malignant leiomyosarcoma, these lesions should be resected.
Recurrence is common after local resection, but most small
leiomyomas can be adequately treated with limited resection.
Lesions > 5 cm should be treated with radical resection because
the risk of malignancy is high. (See Schwartz 11th ed., p. 1303.)
Answer: B
Gastrointestinal stromal tumor (GIST). Gastrointestinal stro-
mal tumors (GIST) are most common in the proximal GI tract
but do occasionally occur in the colorectum (5%–10%) and may
be mistaken for leiomyomas. GISTs are mesenchymal tumors
that arise from the interstitial cells of Cajal. The vast majority
(>95%) of GISTs express CD117 (KIT), and as such, are sensitive
to tyrosine kinase inhibitors (TKIs), such as imatinib mesylate
and sunitinib malate. Risk stratification is based on tumor size
and mitotic activity, and 30% to 50% are malignant. Although
small GISTs may be asymptomatic and discovered incidentally,
larger lesions can cause bleeding, obstruction, or abdominal
pain. Treatment of choice is surgical resection (either local excision or radical resection) with microscopically negative margins,
if possible; however, local recurrence is common. For larger marginally resectable tumors, TKIs (imatinib) can be used to shrink
the tumor. These agents can also be considered for adjuvant therapy after resection and are useful for treating metastatic disease.
(See Schwartz 11th ed., p. 1303.)
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17. Which of the following statements accurately describes
the role of surgical therapy in anal melanoma?
A. Wide local excision should be attempted first for
localized disease.
B. Abdominoperineal resection (APR) is the initial
treatment of choice due to unacceptably high rates of
recurrence with wide local excision.
C. Surgery has no role in anal melanoma.
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Answer: A
Melanoma. Anorectal melanoma is rare, comprising <1% of all
anorectal malignancies and 1% to 2% of melanomas. Diagnosis
is often delayed, and symptoms are attributed to hemorrhoidal
disease. Despite many advances in the treatment of cutaneous
melanoma, prognosis for patients with anorectal disease remains
poor. Overall 5-year survival is <10%, and many patients present with systemic metastasis and/or deeply invasive tumors at
the time of diagnosis. A few patients with anorectal melanoma,
however, present with isolated local or locoregional disease that
is potentially resectable for cure, and both radical resection
(APR) and wide local excision have been advocated. Recurrence is common and usually occurs systemically regardless of
the initial surgical procedure. Local resection with free margins
does not increase the risk of local or regional recurrence, and
APR offers no survival advantage over local excision. Because
of the morbidity associated with APR, wide local excision is
recommended for initial treatment of localized anal melanoma.
In some patients, wide local excision may not be technically
feasible, and APR may be required if the tumor involves a significant portion of the anal sphincter or is circumferential. The
addition of adjuvant chemotherapy, biochemotherapy, vaccines,
or radiotherapy may be of benefit in some patients, but efficacy
remains unproven. (See Schwartz 11th ed., p. 1305.)
18. Which operation for rectal prolapse is associated with
the lowest recurrence rate?
A. Perineal rectosigmoidectomy (Altemeier procedure)
B. Reefing the rectal mucosa (Delorme procedure)
C. Anal encirclement
D. Abdominal rectopexy
19. Which of the following scenarios describes appropriate
use of endoscopy in the setting of volvulus?
A. A 75-year-old man presenting with sigmoid volvulus
and peritonitis, since he needs emergent detorsion
B. An 80-year-old woman presenting with cecal
volvulus, due to the low rates of recurrence of cecal
volvulus following colonoscopic detorsion
C. A 90-year-old woman with sigmoid volvulus and
moderate abdominal tenderness, since she is hemodynamically stable
Answer: D
Because rectal prolapse occurs most commonly in elderly
women, the choice of operation depends in part on the
patient’s overall medical condition. Abdominal rectopexy
(with or without sigmoid resection) offers the most durable
repair, with recurrence occurring in <10% of patients. Perineal rectosigmoidectomy avoids an abdominal operation and
may be preferable in high-risk patients but is associated with
a higher recurrence rate. Reefing the rectal mucosa is effective for patients with limited prolapse. Anal encirclement
procedures generally have been abandoned (See Schwartz
11th ed., p. 1306.)
Answer: C
Unless there are obvious signs of gangrene or peritonitis, the
initial management of sigmoid volvulus is resuscitation followed by endoscopic detorsion. Detorsion is usually most easily accomplished by using a rigid proctoscope, but a flexible
sigmoidoscope or colonoscope may also be effective. A rectal
tube may be inserted to maintain decompression. Although
these techniques are successful in reducing sigmoid volvulus in the majority of patients, the risk of recurrence is high
(up to 40%). For this reason, an elective sigmoid colectomy
should be performed after the patient has been stabilized and
undergone an adequate bowel preparation.
Clinical evidence of gangrene or perforation mandates
immediate surgical exploration without an attempt at endoscopic decompression. Similarly, the presence of necrotic
mucosa, ulceration, or dark blood noted on endoscopy
examination suggests strangulation and is an indication for
operation. If dead bowel is present at laparotomy, a sigmoid
colectomy with end colostomy (Hartmann procedure) may
be the safest operation to perform.
Cecal volvulus. Cecal volvulus results from nonfixation
of the right colon. In the majority of cases, rotation occurs
20. A patient on the trauma wards undergoes abdominal
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computed tomography (CT) for lack of return of bowel
function following operative fixation of pelvic fractures
10 days ago. He has been using high dose opioids for
pain. Imaging is suggestive of Ogilvie syndrome. He is
hemodynamically stable and without evidence of peritonitis. What is the next best step in management?
A. Conduct a discussion with the patient and the hospi-
tal’s pain service to identify alternative medications
to reduce his opioid use.
B. Transfer to the ICU to initiate neostigmine.
C. Consult gastroenterology for colonoscopic
decompression.
D. Proceed to the operating room (OR) for diagnostic
laparoscopy.
around the ileocolic blood vessels and vascular impairment
occurs early, although 10% to 30% of the cecum folds upon
itself (cecal bascule). Plain X-rays of the abdomen show a
characteristic kidney-shaped, air-filled structure in the left
upper quadrant (opposite the site of obstruction), and a
Gastrografin enema confirms obstruction at the level of the
volvulus.
Unlike sigmoid volvulus, cecal volvulus can almost never
be detorsed endoscopically. Moreover, because vascular compromise occurs early in the course of cecal volvulus, surgical
exploration is necessary when the diagnosis is made. Right
hemicolectomy with a primary ileocolic anastomosis can
usually be performed safely and prevents recurrence. Simple
detorsion or detorsion and cecopexy are associated with a
high rate of recurrence. (See Schwartz 11th ed., p. 1307.)
Answer: A
Colonic pseudo-obstruction (Ogilvie syndrome) is a functional disorder in which the colon becomes massively dilated
in the absence of mechanical obstruction. Pseudo- obstruction
most commonly occurs in hospitalized patients and is associated with the use of narcotics, bed rest, and comorbid disease. Pseudo-obstruction is thought to result from autonomic
dysfunction and severe adynamic ileus. The diagnosis is made
based on the presence of massive dilatation of the colon (usually predominantly the right and transverse colon) in the
absence of a mechanical obstruction. Initial treatment consists
of cessation of narcotics, anticholinergics, or other medications that may contribute to ileus. Strict bowel rest and intravenous hydration are crucial. Most patients will respond to
these measures. In patients who fail to improve, colonoscopic
decompression often is effective. However, this procedure is
technically challenging, and great care must be taken to avoid
causing perforation. Up to 40% of patients recur. Intravenous
neostigmine (an acetylcholinesterase inhibitor), administered
as a single 2 mg dose, also is extremely effective in decompressing the dilated colon and is associated with a low rate of recurrence (20%). However, neostigmine may produce transient but
profound bradycardia and may be inappropriate in patients
with cardiopulmonary disease. Because the colonic dilatation
is typically greatest in the proximal colon, placement of a rectal tube is rarely effective. It is crucial to exclude mechanical
obstruction (usually with a Gastrografin enema) prior to medical or endoscopic treatment. (See Schwartz 11th ed., p. 1308.)
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21. In which way do small and large bowel ischemia differ?
A. Small bowel ischemia is more common overall.
B. Large bowel ischemia is typically due to major arte-
rial or venous occlusion, whereas small bowel ischemia is more frequently seen in low flow states.
C. Large bowel ischemia is managed nonoperatively
more frequently than small bowel ischemia.
Answer: C
Intestinal ischemia occurs most commonly in the colon.
Unlike small bowel ischemia, colonic ischemia rarely is associated with major arterial or venous occlusion. Instead, most
colonic ischemia appears to result from low flow and/or small
vessel occlusion. Risk factors include vascular disease, diabetes mellitus, vasculitis, hypotension, and tobacco use. In
addition, ligation of the inferior mesenteric artery during
aortic surgery predisposes to colonic ischemia. Occasionally,
thrombosis or embolism may cause ischemia. Although the
splenic flexure is the most common site of ischemic colitis,
any segment of the colon may be affected. The rectum is relatively spared because of its rich collateral circulation.
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Treatment of ischemic colitis depends on clinical severity.
Unlike ischemia of the small bowel, the majority of patients
with ischemic colitis can be treated medically. Bowel rest and
broad-spectrum antibiotics are the mainstay of therapy, and
80% of patients will recover with this regimen. Hemodynamic
parameters should be optimized, especially if hypotension and
low flow appear to be the inciting cause. Long-term sequelae
include stricture (10%–15%) and chronic segmental ischemia
(15%–20%). Colonoscopy should be performed after recovery to evaluate strictures and to rule out other diagnoses
such as inflammatory bowel disease or malignancy. Failure to
improve after 2 to 3 days of medical management, progression of symptoms, and deterioration in clinical condition are
indications for surgical exploration. In this setting, all necrotic
bowel should be resected. Primary anastomosis should be
avoided. Occasionally, repeated exploration (a second-look
operation) may be necessary. (See Schwartz 11th ed., p. 1309.)
22. Which of the following is the correct pairing of each
internal hemorrhoid classification and its definition?
A. First-degree: no prolapse, visualized endoscopically
only
B. Second-degree: prolapse into the anal canal only
C. Third-degree: prolapse through the anus that requires
manual reduction
D. Fourth-degree: a term reserved for prolapsed hemor-
rhoids that are strangulated
23. An emergency room physician calls you in the middle
of the night. One of your patients, on whom you performed rubber band ligation of internal hemorrhoids in
the office earlier that day, is being seen in the emergency
room (ER) for severe pelvic pain and inability to urinate.
How do you respond?
A. “This is a common scenario after rubber band liga-
tion. The patient should get a prescription for opioid
pain medication and can follow up in my office next
week to ensure the pain is resolved.”
B. “This pain can be seen with urinary retention. The
patient can undergo straight catheterization in the
ER and is appropriate to discharge after demonstrating the ability to void independently.”
C. “The patient should be admitted for broad-spectrum
antibiotics, and I will see the patient after my scheduled cases tomorrow.”
D. “I am concerned about a rare but serious com-
plication. I will be there to examine the patient
immediately.”
Answer: C
Internal hemorrhoids are located proximal to the dentate line
and covered by insensate anorectal mucosa. Internal hemorrhoids may prolapse or bleed, but they rarely become painful
unless they develop thrombosis and necrosis (usually related
to severe prolapse, incarceration, and/or strangulation).
Internal hemorrhoids are graded according to the extent of
prolapse. First-degree hemorrhoids bulge into the anal canal
and may prolapse beyond the dentate line on straining.
Second-degree hemorrhoids prolapse through the anus but
reduce spontaneously. Third-degree hemorrhoids prolapse
through the anal canal and require manual reduction. Fourth-
degree hemorrhoids prolapse but cannot be reduced and are at
risk for strangulation. (See Schwartz 11th ed., p. 1310.)
Answer: D
Other complications of rubber band ligation include urinary
retention, infection, and bleeding. Urinary retention occurs in
approximately 1% of patients and is more likely if the ligation
has inadvertently included a portion of the internal sphincter.
Necrotizing infection is an uncommon, but life-threatening
complication. Severe pain, fever, and urinary retention are
early signs of infection and should prompt immediate evaluation of the patient usually with an examination under
anesthesia. Treatment includes debridement of necrotic tissue, drainage of associated abscesses, and broad-spectrum
antibiotics. Bleeding may occur approximately 7 to 10 days
after rubber band ligation, at the time when the ligated pedicle necroses and sloughs. Bleeding is usually self-limited,
but persistent hemorrhage may require examination under
anesthesia and suture ligation of the pedicle. (See Schwartz
11th ed., p. 1312.)
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24. After drainage of a perianal abscess, for which of the
following patients would a course of antibiotics be
prescribed?
A. Antibiotics are never prescribed as long as source
control has been obtained.
B. A 25-year-old man with approximately 2 cm of cir-
cumferential erythema surrounding the drained
abscess
C. A 40-year-old diabetic patient with a fingerstick glu-
cose value of 310 mg/dL in the emergency room (ER)
D. A 30-year-old woman with a well-drained abscess
and no cellulitis, though this is her third episode of
perianal abscess in the last decade
25. Which of the following is TRUE regarding rectovaginal
fistula?
A. Obstetric injury is a rare cause of rectovaginal fistula.
B. Rectovaginal fistulas in the setting of prior pelvic
radiation can represent cancer recurrence.
C. Rectovaginal fistulas in Crohn disease often heal
spontaneously.
D. Rectovaginal fistulas following obstetric injury typi-
cally require operative repair.
Answer: C
Anorectal abscesses should be treated by drainage as soon as
the diagnosis is established. If the diagnosis is in question,
an examination and drainage under anesthesia are often the
most expeditious ways both to confirm the diagnosis and
to treat the problem. Delayed or inadequate treatment may
occasionally cause extensive and life-threatening suppuration with massive tissue necrosis and septicemia. Antibiotics
are only indicated if there is extensive overlying cellulitis or if
the patient is immunocompromised, has diabetes mellitus, or
has valvular heart disease. Antibiotics alone are ineffective at
treating perianal or perirectal infection. (See Schwartz 11th
ed., p. 1314.)
Answer: B
A rectovaginal fistula is a connection between the vagina and
the rectum or anal canal proximal to the dentate line. Rectovaginal fistulas are classified as low (rectal opening close
to the dentate line and vaginal opening in the fourchette),
middle (vaginal opening between the fourchette and cervix),
or high (vaginal opening near the cervix). Low rectovaginal
fistulas are commonly caused by obstetric injuries or trauma
from a foreign body. Mid-rectovaginal fistulas may result
from more severe obstetric injury, but they also occur after
surgical resection of a mid-rectal neoplasm, radiation injury,
or extension of an undrained abscess. High rectovaginal fistulas result from operative or radiation injury. Complicated
diverticulitis may cause a colovaginal fistula. Crohn disease
can cause rectovaginal fistulas at all levels, as well as colovaginal and enterovaginal fistulas.
Diagnosis. Patients describe symptoms varying from the
sensation of passing flatus from the vagina to the passage of
solid stool from the vagina. Most patients experience some
degree of fecal incontinence. Contamination may result in
vaginitis. Large fistulas may be obvious on anoscopic and/or
vaginal speculum examination, but smaller fistulas may be
difficult to locate. Occasionally, a barium enema or vaginogram may identify these fistulas. Endorectal ultrasound may
also be useful. With the patient in the prone position, installation of methylene blue into the rectum while a tampon is in
the vagina may confirm the presence of a small fistula.
Treatment. The treatment of rectovaginal fistula depends
on the size, location, etiology, and condition of surrounding tissues. Because up to 50% of fistulas caused by obstetric
injury heal spontaneously, it is prudent to wait 3 to 6 months
before embarking on surgical repair in these patients. If the
fistula was caused by a cryptoglandular abscess, drainage of
the abscess may allow spontaneous closure.
Low and mid-rectovaginal fistulas are usually best treated
with an endorectal advancement flap. The principle of this
procedure is based on the advancement of healthy mucosa,
submucosa, and circular muscle over the rectal opening
(the high-pressure side of the fistula) to promote healing
( Fig. 29-3). If a sphincter injury is present, an overlapping
sphincteroplasty should be performed concurrently. Fecal
diversion is rarely required. High rectovaginal, colovaginal, and enterovaginal fistulas are usually best treated via a
transabdominal approach. The diseased tissue, which caused
the fistula (upper rectum, sigmoid colon, or small bowel), is
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CHAPTER 29
Probe in
rectovaginal
fistula
Flap of mucosa
and internal
sphincter muscle
Colon, Rectum, and Anus
Rectal mucosa and
internal sphincter
muscle incised
Attenuated
rectovaginal
septum
Excess flap of
mucosa excised
Internal sphincter
muscle mobilized
FIG. 29-3. Endorectal advancement flap for rectovaginal fistula.
Internal sphincter
muscle approximated
resected and the hole in the vagina closed. Healthy tissue,
such as omentum or muscle, frequently is interposed between
the bowel anastomosis and the vagina to prevent recurrence.
Rectovaginal fistulas caused by Crohn disease, radiation injury, or malignancy almost never heal spontaneously.
In Crohn disease, treatment is based on adequate drainage
of perianal sepsis and nutritional support. An endorectal
advancement flap may be performed if the rectum is spared
from active Crohn disease. Fistulas resulting from radiation
damage are not amenable to local repair with an advancement flap because of damage to the surrounding rectal and
vaginal tissues. Such mid and high rectovaginal fistulas are
occasionally repaired successfully with a transabdominal
approach in which healthy tissue (omentum, muscle, or nonradiated bowel) is interposed between the damaged rectum
and vagina. Fistulas caused by malignancy should be treated
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with resection of the tumor. Because differentiating radiation
damage from malignancy can be extremely difficult, all fistulas resulting from radiation should be biopsied to rule out the
presence of cancer. (See Schwartz 11th ed., pp. 1317–1318.)
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26. A patient is seen in consultation in the emergency
room (ER) after presenting with moderate generalized
abdominal pain. He reports insertion of a rectal foreign
body 3 days ago, which remains in place. He is hemodynamically stable and without peritonitis on examination.
What is the next best step in management?
A. Upright abdominal X-ray to evaluate for free air
B. CT abdomen/pelvis to locate foreign body
C. Removal of foreign body in the ER
D. Proceed to operating room (OR) for laparotomy
27. A patient on the hematology service status post bone
marrow transplant develops abdominal cramping, nausea/vomiting, and diarrhea with specks of bright blood
in it. The general surgery team is consulted and reviews
the available computed tomography (CT) scan, which
shows pneumatosis and stranding of the right colon
without evidence of frank perforation. Upon evaluation,
the patient is noted to have some distension and moderate diffuse abdominal tenderness without peritonitis.
Vitals are within normal limits. What recommendation
should the general surgery consulting team provide?
A. The presence of pneumatosis implies a contained
perforation, so the patient should be taken urgently
to the operating room (OR) for exploration and
resection.
B. Mesenteric ischemia is highest on the differential, and
the gastroenterologist on call should be contacted to
perform a colonoscopy for definitive diagnosis.
C. This is not an uncommon development after bone
marrow transplant. Physical examination is unreliable, so daily CT scans should be obtained to evaluate
for perforation.
D. The patient should be prescribed bowel rest and
broad-spectrum antibiotics with serial abdominal
examinations to evaluate for progression.
Answer: A
Foreign body entrapment in the rectum is not uncommon.
Depending on the level of entrapment, a foreign body may
cause damage to the rectum, rectosigmoid, or descending
colon. Generalized abdominal pain suggests intraperitoneal
perforation. Evaluation of the patient includes inspection of
the perineum and a careful abdominal examination to detect
any evidence of perforation. Plain films of the abdomen are
mandatory to detect free intra-abdominal air.
Foreign bodies lodged low in the rectum may often be
removed under conscious sedation with or without a local
anesthetic block. Objects impacted higher in the rectum
may require regional or general anesthesia for removal. Only
rarely will a laparotomy be required to remove the object,
either through manual manipulation of the object to expel
from the anus, or via colotomy. After removal of the foreign
body, it is crucial to evaluate the rectum and sigmoid colon
for injury. Proctoscopy and/or flexible sigmoidoscopy should
be performed. A hematoma without evidence of perforation
requires no surgical treatment. Perforation of the rectum or
sigmoid colon should be managed as described in the preceding sections. (See Schwartz 11th ed., p. 1323.)
Answer: D
Neutropenic enterocolitis (typhlitis) is a life-threatening
problem with a mortality rate of >50%. This syndrome is
characterized by abdominal pain and distention, fever, diarrhea (often bloody), nausea, and vomiting in a patient with
fewer than 1000 neutrophils/μL blood from any cause (bone
marrow transplantation, solid-organ transplantation, or
chemotherapy). Its etiology is poorly understood. Histologic
features can be seen on biopsy or surgical resection and include
a paucity of inflammatory and leukemic infiltrates but with
mucosal and submucosal edema, villous sloughing, stromal
hemorrhage, and patchy-to-complete epithelial necrosis.
CT scan of the abdomen often shows a dilated cecum with
pericolic stranding. However, a normal-appearing CT scan
does not exclude the diagnosis. Some patients will respond
to bowel rest, broad-spectrum antibiotics, parenteral nutrition, and granulocyte infusion or colony-stimulating factors.
Evidence of perforation, generalized peritonitis, and deterioration in clinical condition are indications for operation.
(See Schwartz 11th ed., pp. 323–324.)
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28. A 74-year-old man with biopsy-proven rectal adenocarcinoma is undergoing a low anterior resection. Which
layers must be stapled through when resecting the distal
portion of resection specimen?
A. Mucosa, submucosa, circular muscle layer, longitudi-
nal muscle layer, and serosa
B. Mucosa, submucosa, longitudinal muscle layer,
circular muscle layer, and serosa
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Colon, Rectum, and Anus
C. Mucosa, submucosa, longitudinal muscle layer,
circular muscle layer
29. A healthy 48-year-old physician with no family history
of caner and who strictly adheres to a high protein, high
fiber diet, exercises five times per week for 50 minutes,
and takes vitamin C supplements daily performs a fecal
occult blood test (FOBT) on herself and tests positive.
Should she have any further colon screening?
A. No, vitamin C can produce a false positive result.
B. Yes, all positive FOBT requires further investigation
with a colonoscopy.
C. Yes, all positive FOBT requires further investigation
with FOBT in 1 year.
D. No, she has no risk factors for colon cancer and
should follow the United States Preventive Services Task Force (USPSTF) screening guidelines for
colorectal cancer.
Answer: C
The wall of the colon and rectum are made of five separate
layers: mucosa, submucosa, circular muscle layer, longitudinal muscle layer, and serosa. The mid and lower rectum
lack serosa so this layer would not be stapled through if the
surgeon were stapling through the mid or lower rectum.
(See Schwartz 11th ed., p. 1260.)
Answer: B
FOBT has been a nonspecific test for peroxidase contained
in hemoglobin; consequently, occult bleeding from any
gastrointestinal source will produce a positive result. Similarly, many foods (red meat, some fruits and vegetables, and
vitamin C) will produce a false-positive result. Any positive
FOBT mandates further investigation, usually by colonoscopy. (See Schwartz 11th ed., p. 1293.)
30. A 76-year-old man undergoes an emergent sigmoidectomy for a perforated colon mass. The surgeon performs a Hartmann procedure and brings up a colostomy.
In an emergency setting, where is the most appropriate
location to seat a colostomy?
A. Above the beltline, within the rectus abdominus
muscle, away from the costal margin
B. Below the beltline, within the rectus abdominus
muscle, near the iliac crest
C. Above the beltline, within the rectus abdominus
muscle, near the costal margin
D. Below the beltline, within the rectus abdominus
muscle, away from the iliac crest
31. A 50-year-old woman who underwent a total colectomy
with ileal pouch-anal reconstruction 5 years ago presents
to the emergency room with diarrhea, fever, 2 weeks of
malaise, and severe abdominal pain. What is the most
appropriate differential diagnosis?
A. Parasitic infection, ulcerative colitis of the remaining
rectal cuff, undiagnosed Crohn disease
B. Bacterial or viral infection, undiagnosed Crohn dis-
ease, and pouchitis
C. Rectal cancer of remaining rectal cuff, bacterial or
viral infection, and undiagnosed Crohn disease
D. Parasitic infection, bacterial or viral infection, and
pouchitis
Answer: A
In an emergency operation, like this one, where the stoma site
has not been marked, an attempt should be made to place a
stoma within the rectus muscle and away from both the costal
margin and iliac crest. In emergencies, placement high on the
abdominal wall is preferred to a low-lying site. (See Schwartz
11th ed., pp. 1275–1276.)
Answer: B
This patient is likely presenting with pouchitis. Pouchitis is
an inflammatory condition that affects both ileoanal pouches
and continent ileostomy reservoirs. The incidence of pouchitis ranges from 30% to 55%. Symptoms include increased
diarrhea, hematochezia, abdominal pain, fever, and malaise.
Diagnosis is made endoscopically with biopsies. Differential
diagnosis includes infection and undiagnosed Crohn disease.
(See Schwartz 11th ed., p. 1278.)
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32. An 18-year-old woman is undergoing workup to determine if she has ulcerative colitis, Crohn disease, or
indeterminate colitis. What diagnostic findings would
indicate that she has ulcerative collitis?
A. Atrophic mucosa, crypt abscesses, inflammatory
pseudopolyps, scarred and shortened colon, continuous involvement of rectum and colon
B. Mucosal ulcerations, noncaseating granulomas,
fibrosis, strictures, and fistulas in the colon with deep
serpiginous ulcers
C. Atrophic mucosa, noncaseating granulomas, stric-
tures, “cobblestone” appearance on endoscopy
D. Mucosal ulcerations, crypt abscesses, inflammatory
pseudopolyps, continuous involvement of colon and
rectum
Answer: A
Ulcerative colitis is a mucosal process in which the colonic
mucosa and submucosa are infiltrated with inflammatory
cells. The mucosa may be atrophic, and crypt abscesses are
common. Endoscopically, the mucosa is frequently friable
and may possess multiple inflammatory pseudopolyps. In
long-standing ulcerative colitis, the colon may be foreshortened and the mucosa replaced by scar. A key feature of ulcerative colitis is the continuous involvement of the rectum and
colon; rectal sparing or skip lesions suggest a diagnosis of
Crohn disease. Crohn disease is a transmural inflammatory
process that can affect any part of the gastrointestinal tract
from mouth to anus. Mucosal ulcerations, an inflammatory
cell infiltrate, and noncaseating granulomas are characteristic
pathologic findings. Chronic inflammation may ultimately
result in fibrosis, strictures, and fistulas in either the colon or
small intestine. The endoscopic appearance of Crohn colitis is
characterized by deep serpiginous ulcers and a “cobblestone”
appearance. (See Schwartz 11th ed., p. 1280.)
CHAPTER 29
Colon, Rectum, and Anus
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