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Diagnostic In-Training Exam 2003 1

Section IV – Gastrointestinal Radiology

135. You are shown a radiograph from a small bowel follow-through in a 40-year-old woman with abdominaldistension and chronic diarrhea (Figure 1). Which one of the following is the MOST likely diagnosis?

A. Crohn’s disease

B. Sprue

C. Scleroderma

D. Giardia infection

E. Eosinophilic enteritis

Figure 1

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Section IV – Gastrointestinal RadiologyQuestion #135

Findings: The radiograph demonstrates dilation of the small bowel with closely spaced normal thickness folds.

Rationales:

A) Incorrect. Crohn’s disease involves the small bowel in 75% of patients at the time of presentation. Affectedsegments show fold thickening and ulceration. Sinus tracts and fistulae are also noted. Surrounding fibrofattyproliferation may produce a mass effect or displace adjacent bowel. None of these findings, however, are notedhere.

B) Incorrect. Sprue or gluten sensitive enteropathy produces villous atrophy and radiographically shows reversalof the normal fold pattern with loss of normal jejunal folds and an increased number of folds per inch in theilium. Transient intussusceptions, hypomotility, and flocculation of barium can also be seen. However, noneof these findings are present on this film.

C) Correct. Scleroderma causes smooth muscle atrophy and fibrosis. Radiographically the small bowel appearsdilated with closely spaced but normal caliber valvulae conniventes as shown in this radiograph. Wide mouthdiverticula are frequently noted on the mesenteric side of the bowel, although they are not seen here.Hypomotility is common and along with the dilation can produce bacterial overgrowth syndrome and thesymptoms noted here. The small bowel is the second most commonly affected portion of the GI tract inscleroderma.

D) Incorrect. Giardia lamblia is a common intestinal parasite. The radiographic findings in this protozoal infectionare most common in the duodenum and proximal jejunum and consist of thickened folds associated withbowel irritability, hypermotility, and increased secretion.

E) Incorrect. Eosinophilic enteritis is a benign infiltration of the bowel wall with eosinophils. The etiology isunclear but the disease responds rapidly to steroids. Radiographically fold thickening that can be nodular isnoted most prominently in the proximal small bowel. Gastric antral involvement is also common.

Diagnostic In-Training Exam 2003 3

Section IV – Gastrointestinal Radiology

136. You are shown three images from a contrast enhanced CT in a 33-year-old man with a 4 day history ofabdominal pain (Figures 2A, 2B and 2C). Which one of the following is the MOST likely diagnosis?

A. Mesenteric adenitis

B. Appendicitis

C. Crohn’s disease

D. Carcinoid

E. Epiploic appendagitis

Figure 2A

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Section IV – Gastrointestinal Radiology

Figure 2B

Figure 2C

Diagnostic In-Training Exam 2003 5

Section IV – Gastrointestinal RadiologyQuestion #136

Findings: The CT image demonstrates an enlarged and partially air filled appendix with an appendicolith noted atits juncture with the cecum. There is extensive periappendiceal and pericecal inflammation.

Rationales:

A) Incorrect. Mesenteric adenitis is a benign inflammatory process usually involving the mesenteric lymph nodesin the right lower quadrant. On CT, it appears as a cluster of enlarged nodes. Occasionally ileal or cecal wallthickening is noted. The extensive perienteric and periappendiceal inflammation shown here would not be seen.

B) Correct. Appendicitis is usually 2ry to luminal obstruction. In this case, a discreet high-density appendicolith isnoted at the juncture of the cecum and appendix. The appendix is enlarged and there is significant inflammatorystranding about the appendix with wall thickening noted involving the cecal tip. The findings are characteristicof appendicitis.

C) Incorrect. Crohn’s disease is an idiopathic inflammatory condition noted predominantly in the small and largebowel. On CT wall thickening is noted in the involved bowel with fibrofatty proliferation often also seen.Isolated involvement of the appendix would be extremely unusual.

D) Incorrect. Carcinoid is a slow growing tumor derived from enterochromaffin cells. Approximately 50 % ofcarcinoids are found in the appendix. The lesions typically appear as a small mural mass on CT. Nodal metastasisin the mesentery can show extensive surrounding desmoplasia and retraction. Although appendiceal carcinoidcan present as an appendicitis 2ry to luminal obstruction, this would not be the most likely diagnosis.

E) Incorrect. Epiploic Appendagitis is a rare inflammatory condition resulting from either appendageal torsionor spontaneous venous thrombosis of the draining vein. CT findings of epiploic appendagitis include a smallparacolic fat lesion with adjacent inflammatory stranding. A central high attenuating dot and or thickening inthe adjacent bowel and peritoneum is also noted.

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Section IV – Gastrointestinal Radiology

137. You are shown a radiograph of the gastric fundus from a biphasic upper gastrointestinal exam (UGI) (Figure3A) along with a CT scan (Figure 3B) through the upper abdomen in a 62-year-old man with melena.Which one of the following is the MOST likely diagnosis?

A. Lymphoma

B. Adenocarcinoma

C. Brunner’s gland hamartoma

D. Carcinoid

E. Leiomyoma

Figure 3A

Figure 3B

Diagnostic In-Training Exam 2003 7

Section IV – Gastrointestinal RadiologyQuestion #137

Findings: The radiograph from the UGI and CT demonstrates a smooth bordered rounded filling defect in thegastric fundus with a central ulceration. The lesion appears to arise from the gastric wall with an abrupt margin withthe remainder of the wall.

Rationales:

A) Incorrect. The stomach is the most common site of lymphomatous involvement in the GI tract, but gastriclymphoma makes up only 3% of all gastric malignancy. Radiographically lymphoma can appear as aninfiltrative, ulcerative, or nodular mass that often mimics the appearance of adenocarcinoma. The antrum andbody are most commonly involved. The smoothly and very discreetly marginated mass seen on the radiographand CT in this case would be unusual for lymphoma.

B) Incorrect. Adenocarcinoma is the most common gastric malignancy making up 95% of cancers. They canpresent as an infiltrative, either polypoid or ulcerative mass. A linitis plastica appearance is also noted. It wouldbe unusual however for an adenocarcinoma to present as the rounded submucosal process shown in this case.

C) Incorrect. Brunner’s glands occur in the duodenum and secrete alkaline mucus. Hyperplastic changes of theglands may produce a small mass like lesion. These glands do not occur in the gastric fundus nor do Brunner’sgland hamartomas become this large

D) Incorrect. Less than 5% of gastrointestinal carcinoid tumors are located in the stomach. Radiographically theyappear as small (1-4 cm) submucosal masses. Central ulceration may occur.

E) Correct. Leiomyomas make up 90% of mesenchymal gastric tumors. They typically appear as a submucosalmass with smooth and sharply circumscribed margins. The majority has an endogastric growth pattern withabout 20% showing an exogastric or endo-exogastric configuration. Although lesions are usually less than 3 cm,lesions as large as 25 cm have been reported. Central ulceration is not uncommon, being noted in 50-70% ofleiomyomas greater than 2 cm in size.

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Section IV – Gastrointestinal Radiology

138. You are shown a single image from an abdominal CT in a 67-year-old woman with abdominal pain(Figure 4). Which one of the following is the MOST likely diagnosis?

A. Gastroduodenal artery pseudoaneurysm

B. Pseudocyst

C. Pancreatic adenocarcinoma

D. Superior mesenteric vein thrombosis

E. Peripancreatic adenopathy

Figure 4

Diagnostic In-Training Exam 2003 9

Section IV – Gastrointestinal RadiologyQuestion #138

Findings: The image demonstrates thrombosis of the superior mesenteric vein.

Rationales:

A) Incorrect. The gastroduodenal artery is located on the ventral surface of the head of the pancreas. GDApseudoaneurysm can occur as sequelae of pancreatitis and present as an enhancing mass in the head of thepancreas. Although the appearance would be possible with a thrombosed pseudoaneurysm, its location wouldnot be consistent with the GDA.

B) Incorrect. Pancreatic pseudocysts form as a sequelae of pancreatitis. They are usually located in or adjacent tothe pancreas although less commonly they can be seen in locations that are more distant.

C) Incorrect. Pancreatic adenocarcinoma is the most common pancreatic malignancy and typically presents as anill-defined hypo enhancing pancreatic mass.

D) Correct. The superior mesenteric vein is located adjacent and medial to the pancreatic head, usually to theright, and slightly anterior to the superior mesenteric artery. Thrombosis of the SMV is associated with a varietyof factors including infection, hypercoagulable states, and recent surgery. Hyper enhancment of the vein wall,while not uncommon, or residual flow about the thrombus is noted.

E) Incorrect. Low-density adenopathy can be seen in a variety of diseases including mycobacterial infection,Whipple’s disease, and testicular neoplasms. This location and appearance however would be unusual andwould not explain the appearance of the SMV.

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Section IV – Gastrointestinal Radiology

139. You are shown two images from a CT scan in a 30-year-old woman being worked up for a liver mass.Figure 5A was obtained during the portal venous phase. Figure 5B is a 4 minute delayed image. Which one ofthe following is the MOST likely diagnosis?

A. Hypervascular metastasis

B. Hepatic hemangioma

C. Hepatic adenoma

D. Fibronodular hyperplasia

E. Fibrolamellar carcinoma

Figure 5A

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Section IV – Gastrointestinal Radiology

Figure 5B

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Section IV – Gastrointestinal RadiologyQuestion #139

Findings: The images show a large well-circumscribed lesion in the right lobe of the liver that demonstratesnodular peripheral discontinuous enhancement that is equal to that of the vessels. The delayed image shows gradualperipheral fill-in.

Rationales:

A) Incorrect. Although most metastases are hypovascular relative to normal liver, several are hypervascularparticularly in the early arterial phase. These include renal cell cancer, islet cell tumors, carcinoid as well asoccasionally sarcomas, melanoma, adrenal tumors and breast cancer. Most become iso or hypo attenuating onmore delayed scanning. None would demonstrate the discontinuous nodular peripheral enhancement shownhere with persistent fill-in over time.

B) Correct. Hemangioma is the most common benign hepatic tumor. On enhanced CT or MRI, they typicallyshow a discontinuous nodular peripheral enhancement that is equal to that of the vessels and gradually fills inover time as shown here.

C) Incorrect. Hepatic adenomas are benign tumors that occur most commonly in women. They are associatedwith oral contraceptive use. They typically show early homogenous enhancement with rapid fading toisoattenuation.

D) Incorrect. FNH is the second most common benign hepatic tumor and is more common in women.Radiographically it appears as a well-circumscribed lesion with homogenous early enhancement. Delayedimages typically show fading to isoattenuation with normal liver. A central scar is frequently present.

E) Incorrect. Fibrolamellar carcinoma is a subtype of hepatocellular carcinoma occurring most commonly inyounger patients. It has a better prognosis than HCC and is not associated with underlying cirrhosis. On CT,it typically appears as a large lesion with heterogeneous enhancement and often a central calcified scar.