3

Stomach

Gastric Neoplasms

Overview

Adenocarcinoma (>90%), gastric lymphoma (∼3% to 5%), gastrointestinal stromal tumors (GISTs) (∼3%)

Clinical Presentation

Weight loss, early satiety, abdominal pain, nausea, vomiting

Dysphagia if tumor is in the proximal stomach (cardia)

Gastric adenocarcinoma metastasis

• Virchow’s node: Metastasis to the left supraclavicular node

• Sister Mary Joseph nodule: Metastasis to the periumbilical region

• Krukenberg tumor: Metastasis to the ovary

• Blumer’s shelf: Metastasis to the pouch of Douglas

Diagnosis

EGD is the gold standard for tissue diagnosis

EUS to assess for depth of invasion and lymphadenopathy

CT abdomen/pelvis and CXR for staging purposes

Treatment

Adenocarcinoma

• Diagnostic laparoscopy to assess for metastatic disease

• Surgical resection with 5 cm margins with D1 or D2 nodal dissection

• Neoadjuvant or adjuvant chemotherapy depending on the stage

Lymphoma

• All are nonHodgkin type, most are low grade MALT (mucosal associated lymph tissue)

• Low-grade MALT: Likely a result of chronic Helicobacter pylori infection

Antibiotic treatment for H. pylori

Radiation ± chemotherapy for persistent disease after H. pylori treatment

• High-grade MALT: Chemotherapy and radiation therapy

GIST

• Arises from interstitial cells of Cajal (intestinal pacemaker cells)

• Due to c-kit mutation

• Resection with negative margins

• Consider imatinib (Gleevec) if

tumor >5 cm in size

more than 5 mitotic figures per 50 high-power field

nongastric location

tumor rupture

KIT—positive unresectable, metastatic, or recurrent disease

RADIOLOGY

Gastric Cancer

Plain film findings

• Gastric mass is usually not seen on plain radiographs

• Omental calcified metastases may sometimes be visible

Upper GI findings

• If small, gastric adenocarcinomas will manifest as a raised ulcer with surrounding mucosal edema

Folds are often thickened, irregular, or nodular

Ulcerations, if present, are irregular in shape and do not extend beyond the gastric lumen

If the antrum is involved, it may be severely narrowed or obstructed

CT findings (Fig. 3.1)

• Focal wall thickening with or without ulceration, mass, or diffuse wall thickening

• CT is superior to barium studies to evaluate for the extent of disease

• Extension of tumor into adjacent organs and omental carcinomatosis can be seen

• Presence or absence of regional lymphadenopathy (adenopathy in the left gastric, porta hepatis, and peripancreatic regions) and presence of liver metastases can be evaluated

FIGURE 3.1

A. Liver

B. Descending aorta

C. Vertebra

D. Spleen

E. Splenic cyst

Gastric Lymphoma

Upper GI findings

• Focal or diffuse gastric fold thickening

• Mass with nodular margins and luminal narrowing may be seen

CT findings (Fig. 3.2)

• Focal or diffuse fold thickening, which can be associated with regional lymphadenopathy

FIGURE 3.2 A–C

A. Liver

B. Kidney

C. IVC

D. Descending aorta

E. Vertebra

F. Spleen

G. Small bowel loops

H. Bladder

FIGURE 3.2 A

FIGURE 3.2 B

FIGURE 3.2 C

GIST Tumor

Plain film findings

• Nonspecific mass indenting or displacing the gastric bubble may be seen

• Upper GI Findings

Intraluminal filling defect arising from the wall, forming smooth, obtuse angles with the rest of the stomach

CT findings (Fig. 3.3)

• Mass arising from the gastric wall, usually with an exophytic growth pattern

• Central areas of low attenuation indicate hemorrhage or necrosis

MRI findings

• Solid portions of tumor are T1 hypointense (pre-contrast) and T2 hyperintense

• Hemorrhage within tumor will manifest with variable T1 and T2 signals

• Heterogeneous enhancement

FIGURE 3.3 A–C

A. Liver

B. Descending aorta

C. Vertebra

D. Spleen

E. IVC

F. Kidney

G. Psoas muscle

H. Adnexal cyst

FIGURE 3.3 A

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