Gastric metastases

Gastric metastases are rare, found in less than 2% of patients who die of a carcinoma ⁶.

Epidemiology

Usually affects the middle-aged and elderly population. Affects males and females equally without predilection.

Clinical presentation

The patient may be asymptomatic, but the most common signs and symptoms include:

• weight loss
• pain
• haematemesis
• melaena
• palpable mass

Pathology

Gastric metastases are usually haematogenous metastases, but the stomach may be involved less frequently by the lymphatic spread or by direct extension of tumour from neighbouring structures or mesenteric reflections. 

Habitual primary sites that lead to gastric metastases include the oesophagus, skin (malignant melanoma - sometimes considered the most common ²), lung, cervix, breast, sigmoid colon, testis ¹,renal cell carcinoma ⁷, and prostate ⁸., and ovarian adenocarcinoma⁹

A solitary metastasis can be much more common than multiple metastases ³. 

Location

There may be a predilection for the middle and upper thirds of the stomach ³.

Macroscopic appearance

• may be solitary or multiple
• classic "leather bottle" appearance of the stomach
• polypoid, ulcerated or cavitated masses

Microscopic appearance

The microscopic features vary greatly depending on the primary cancer.

Radiographic features

Ultrasound

Endoscopic ultrasonography may show a hypoechoic mass disrupting normal wall layers.

CT​

• direct invasion or lymphatic spread to stomach
  • distal oesophageal carcinoma
    • polypoid, lobulated mass in gastric fundus
    • radiologically indistinguishable from primary gastric carcinoma
  • pancreatic carcinoma
    • pancreatic tumour will be evident
    • irregular extrinsic gastric compression
  • omental and peritoneal metastases: ovary, uterus, breast, pancreas
    • lesions as small as 1 cm can be seen
    • lacy reticular pattern to bulky masses /omental cake displace and indent gastric wall
• haematogenous spread to stomach
  • malignant melanoma
    • "target" or bull's-eye lesions, nodular intramural cavitated lesions
  • breast cancer: "leather bottle" appearance (linitis plastica)
    • markedly thickened gastric wall demonstrating enhancement, preservation of mucosal folds
    • mimics primary scirrhous carcinoma of stomach

Treatment and prognosis

Gastric metastases mark advanced disease, and the prognosis is considered poor ¹.

Differential diagnosis

• gastritis (erosive type): multiple punctate collections of barium enveloped by thin radiolucent halos of oedematous mucosa
• pancreatitis
• gastric adenocarcinoma
• gastrointestinal stromal tumour (GIST)
• gastric pseudolymphoma