Metastasis to the stomach refers to the spread of other primary malignant tumors to the stomach and accounts for approximately 2% of all gastric malignancies. The most common primary tumors that metastasize to the stomach are breast carcinoma (especially lobular type), malignant melanoma, lung carcinoma, ovarian carcinoma, and renal cell carcinoma. Spread can occur through hematogenous, lymphatic, direct invasion, or peritoneal dissemination routes. On imaging, it presents as submucosal nodules (hematogenous), diffuse wall thickening (linitis plastica-like, especially breast lobular carcinoma), or serosal implants (peritoneal spread).
Age Range
40-80
Peak Age
60
Gender
Equal
Prevalence
Uncommon
Metastasis to the stomach occurs through four main pathways: (1) Hematogenous spread — the most common route where melanoma, lung, breast, and renal carcinomas settle in the gastric submucosa; tumor emboli carried by arterial supply exit submucosal vessels forming nodular lesions visible as submucosal enhancing nodules on CT. (2) Lymphatic spread — breast and lung carcinomas infiltrate the gastric wall through lymphatic channels causing diffuse thickening. (3) Direct invasion — pancreatic, colonic, or retroperitoneal tumors may directly invade the gastric wall. (4) Peritoneal dissemination — ovarian, colonic, and pancreatic carcinomas implant on the gastric serosa via the peritoneal cavity. E-cadherin loss in breast lobular carcinoma (CDH1 mutation/epigenetic silencing) creates the same infiltrative pattern as gastric diffuse adenocarcinoma producing a linitis plastica-like appearance; the morphological similarity between these two entities reflects the common molecular mechanism.
The most characteristic finding of hematogenous metastases to the stomach (especially melanoma) is submucosal nodules with central ulceration. Seen as 'bull's-eye' or 'target' lesions on barium study. On CT, it appears as central hypodensity/ulceration surrounded by an enhancing ring. Multiple bull's-eye lesions nearly pathognomonically support the diagnosis of metastasis.
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In the arterial phase, enhancing submucosal nodule(s) measuring [X] mm in the gastric wall are noted, consistent with metastasis in the setting of known [primary].
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In the portal venous phase, diffuse gastric wall thickening and fat plane obliteration are noted, consistent with metastatic disease along with concurrent liver metastases and peritoneal nodules.
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Progressive enhancement in gastric wall thickening is noted in the delayed phase, consistent with metastatic infiltration in the setting of known breast carcinoma.
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On MRI, T1W hyperintense submucosal nodules in the gastric wall are noted consistent with melanoma metastasis / diffuse T2W hyperintense thickening and diffusion restriction in the gastric wall consistent with metastatic infiltration.
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On PET-CT, FDG uptake with SUVmax: [X] is noted in the gastric wall, consistent with metastasis in the setting of known [primary tumor].
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On barium study, multiple 'bull's-eye' lesions in the gastric wall are noted, consistent with metastatic disease.
Criteria
Malignant melanoma is one of the most common tumors metastasizing to the GI tract and typically presents as multiple submucosal nodules in the stomach. It creates classic 'bull's-eye' lesions. On MRI, melanotic lesions show hyperintense signal on T1W (pathognomonic). PET-CT shows high FDG uptake. Gastric involvement is usually part of widespread metastatic disease.
Distinct Features
Criteria
Breast lobular carcinoma is the most common metastatic tumor causing linitis plastica-like diffuse gastric infiltration. It shows diffuse infiltrative growth due to E-cadherin loss. On CT, diffuse concentric wall thickening and delayed enhancement may be indistinguishable from primary linitis plastica. Immunohistochemistry (GATA3+, ER+, E-cadherin-) is critical for differential diagnosis. It can make late metastasis years after primary diagnosis.
Distinct Features
Criteria
Lung carcinoma metastases typically appear as submucosal nodules or polypoid lesions in the stomach. Small cell lung carcinoma can also cause diffuse infiltration. PET-CT shows high FDG uptake. Usually part of widespread metastatic disease with other organ metastases (brain, bone, adrenal) accompanying.
Distinct Features
Distinguishing Feature
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Urgency
Management
Biopsy
Not NeededFollow-up
Gastric metastasis indicates advanced disease and requires systemic therapy. Identification of the primary tumor is essential for treatment planning. Palliative intervention may be needed for obstruction or bleeding.