Gastric Carcinoma

 Polypoid or circumferential mass with no peristalsis through lesion



• Best imaging tool
image Double-contrast upper GI series, CECT, EUS




TOP DIFFERENTIAL DIAGNOSES




• Normal variant

• Benign gastric (peptic) ulcer

• Gastritis

• Gastric metastases and lymphoma

• Gastric stromal tumor (GIST)

• Caustic gastritis

• Pancreatitis (extrinsic inflammation)

• Ménétrier disease


PATHOLOGY




• Risk factors
image Helicobacter pylori (3-6x ↑ risk), pernicious anemia (2-3x ↑ risk)

image Diet heavy in nitrites or nitrates; salted, smoked, poorly preserved food


CLINICAL ISSUES




• Most common signs/symptoms
image Anorexia, weight loss, anemia, pain; can be asymptomatic

• Diagnosis by endoscopic biopsy and histology


DIAGNOSTIC CHECKLIST




• Image interpretation pearls
image Can be ulcerative, polypoid, or infiltrative (scirrhous type) ± local and distant metastases

image Beware of gastric fundus tumor simulating achalasia on esophagram

image
(Left) Graphic shows a large intraluminal mass with a broad base and irregular surface.


image
(Right) CECT in a 41-year-old woman shows mural thickening of soft tissue density image, representing an infiltrative gastric carcinoma.

image
(Left) More cephalad section in the same patient shows circumferential thickening of the gastric wall image that severely limits distensibility.


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(Right) CT through the pelvis shows a collection of ascites image and bilateral adnexal masses image. 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
image Polypoid or circumferential mass with no peristalsis through lesion (at fluoroscopy)

• Morphology
image Polypoid, ulcerated, infiltrative lesions


Fluoroscopic Findings




• Early (elevated, superficial, shallow)
image Type 1: Elevated polypoid lesion protruding > 5 mm into lumen

image Type 2: Superficial plaque-like lesion with mucosal nodularity/ulceration

image 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
image 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)

image Intraluminal mass

• Gastric cancers are often scirrhous
image Those arising in antrum may cause gastric outlet obstruction
– Look for nodular thickened folds, absence of peristalsis

image Linitis plastic (“leather bottle”)
– Small, nondistensible, nonperistaltic stomach

– Caused by diffuse infiltration of gastric wall

image 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
image Polypoid cancer can be lobulated or fungating

image Lesion on dependent or posterior wall: Filling defect in barium pool

image Lesion on nondependent or anterior wall: Etched in white by thin layer of barium trapped between mass and adjacent mucosa

image Prolapsed polypoid antral carcinoma into duodenum: Filling defect in barium pool

image Ulcerated carcinoma: 70% of all gastric cancers

• Malignant ulcer (in profile)
image Intraluminal location within tumor

image Tumor surrounding ulcer forms acute angle with gastric wall

image Clubbed/nodular folds radiating to edge of ulcer crater

• Malignant ulcer (en face)
image Irregular, scalloped, angular, stellate borders

image Converging folds to ulcer: Blunted, nodular, clubbed, fused

image Ulcer on nondependent/anterior wall: Double-ring shadow (edge of tumor and edge of ulcer)

image Prone compression view: Filling of ulcer crater within discrete tumor on anterior wall

• Carman-Kirkland meniscus complex (lesser curvature antrum or body)
image Broad, flat lesion; central ulceration, elevated margins

image 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
image Irregular narrowing of stomach with nodularity and mucosal spiculation

image May cause gastric outlet obstruction if advanced

• Scirrhous carcinoma (5-15%): Usually arise near pylorus, extend up
image Linitis plastica (“leather bottle”): Irregular narrowing and rigidity
– Diffuse infiltration (nodularity, spiculation, ulceration, or thickened irregular folds)

image 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
image Polypoid mass ± ulceration

image Focal wall thickening with mucosal irregularity or focal infiltration of wall

image Ulceration: Gas-filled ulcer crater within mass

image Infiltrating carcinoma: Wall thickening with loss of normal rugal fold pattern
– Wisp-like perigastric soft tissue stranding: Perigastric fat extension

image Scirrhous carcinoma: Markedly enhancing thickened wall on dynamic CT

image Mucinous carcinoma: ↓ attenuation of thickened wall (↑ mucin); calcification seen

image Carcinoma of cardia: Irregular soft tissue thickening; lobulated mass

• Hematogenous metastases
image Liver 37%, lung 16%, bone 16%

image All other sites are < 10% (brain, adrenal, pleural, etc.)

• Peritoneal metastases
image Seeding of peritoneal cavity is common
– Malignant ascites and peritoneal nodules or masses

Nov 16, 2016 | Posted by in GASTROINTESTINAL IMAGING | Comments Off on Gastric Carcinoma

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