Diet heavy in nitrites or nitrates; salted, smoked, poorly preserved food
CLINICAL ISSUES
• Most common signs/symptoms
Anorexia, weight loss, anemia, pain; can be asymptomatic
• Diagnosis by endoscopic biopsy and histology
DIAGNOSTIC CHECKLIST
• Image interpretation pearls
Can be ulcerative, polypoid, or infiltrative (scirrhous type) ± local and distant metastases
Beware of gastric fundus tumor simulating achalasia on esophagram
(Left) Graphic shows a large intraluminal mass with a broad base and irregular surface.
(Right) CECT in a 41-year-old woman shows mural thickening of soft tissue density , representing an infiltrative gastric carcinoma.
(Left) More cephalad section in the same patient shows circumferential thickening of the gastric wall that severely limits distensibility.
(Right) CT through the pelvis shows a collection of ascites and bilateral adnexal masses . The right adnexal mass is mostly cystic with a contrast-enhancing rim of soft tissue, while the left mass is more solid than cystic. At surgery, gastric carcinoma and bilateral ovarian metastases (Krukenberg tumors) were confirmed.
TERMINOLOGY
Definitions
• Malignancy arising from gastric mucosa
IMAGING
General Features
• Best diagnostic clue
Polypoid or circumferential mass with no peristalsis through lesion (at fluoroscopy)
• Morphology
Polypoid, ulcerated, infiltrative lesions
Fluoroscopic Findings
• Early (elevated, superficial, shallow)
Type 1: Elevated polypoid lesion protruding > 5 mm into lumen
Type 2: Superficial plaque-like lesion with mucosal nodularity/ulceration
Type 3: Shallow, irregular ulcer crater with adjacent nodular mucosa, clubbing/fusion/amputation of radiating folds
• 3 major fluoroscopic patterns on double-contrast upper GI series
Malignant ulcer
– Irregular ulcer crater
– Distortion or obliteration of surrounding areae gastricae
– Nodular, irregular, clubbed, or amputated folds that do not extend to edge of ulcer crater
– Ulcer does not project beyond expected contour of stomach (in profile)
Intraluminal mass
• Gastric cancers are often scirrhous
Those arising in antrum may cause gastric outlet obstruction
– Look for nodular thickened folds, absence of peristalsis
Linitis plastic (“leather bottle”)
– Small, nondistensible, nonperistaltic stomach
– Caused by diffuse infiltration of gastric wall
Pseudoachalasia:Gastric fundus carcinoma may invade distal esophagus and destroy myenteric plexus
– Resulting esophageal obstruction, dilated lumen, diminished peristalsis may be mistaken for primary achalasia
– Distinction: Look for nodular folds, mass in gastric fundus
• Advanced
Polypoid cancer can be lobulated or fungating
Lesion on dependent or posterior wall: Filling defect in barium pool
Lesion on nondependent or anterior wall: Etched in white by thin layer of barium trapped between mass and adjacent mucosa
Prolapsed polypoid antral carcinoma into duodenum: Filling defect in barium pool
Ulcerated carcinoma: 70% of all gastric cancers
• Malignant ulcer (in profile)
Intraluminal location within tumor
Tumor surrounding ulcer forms acute angle with gastric wall
Clubbed/nodular folds radiating to edge of ulcer crater
• Malignant ulcer (en face)
Irregular, scalloped, angular, stellate borders
Converging folds to ulcer: Blunted, nodular, clubbed, fused
Ulcer on nondependent/anterior wall: Double-ring shadow (edge of tumor and edge of ulcer)
Prone compression view: Filling of ulcer crater within discrete tumor on anterior wall
• Carman-Kirkland meniscus complex (lesser curvature antrum or body)
Broad, flat lesion; central ulceration, elevated margins
Prone compression view (mass on anterior wall): Radiolucent halo filling defect due to elevated edges; meniscoid ulcer-convex inner border, concave outer border
• Infiltrating: 5-15% of all gastric cancers
Irregular narrowing of stomach with nodularity and mucosal spiculation
May cause gastric outlet obstruction if advanced
• Scirrhous carcinoma (5-15%): Usually arise near pylorus, extend up
Linitis plastica (“leather bottle”): Irregular narrowing and rigidity
– Diffuse infiltration (nodularity, spiculation, ulceration, or thickened irregular folds)
Localized tumor: Short, annular lesion/shelf-like proximal borders in prepyloric region of antrum
CT Findings
• Primary tumor
• Negative contrast agents (water or gas) facilitate visualization of lesions
Polypoid mass ± ulceration
Focal wall thickening with mucosal irregularity or focal infiltration of wall
Ulceration: Gas-filled ulcer crater within mass
Infiltrating carcinoma: Wall thickening with loss of normal rugal fold pattern