Adenocarcinoma of the Stomach
Definition
- Malignant gland forming neoplasm of the stomach, exclusive of the EGJ and gastric cardia
Covered separately:
Diagnostic Criteria
- Carcinomas of the proximal stomach that cross the EGJ and have their centers within 5 cm of the junction are considered with and staged as esophageal
- There are a number of classifications proposed for gastric adenocarcinoma
- Based on macroscopic and/or microscopic features
- Literature comparing these classifications as independent prognostic features is conflicting
- Staging is far more important for prediction of survival than any of these classifications
- Early carcinoma is defined as limited to mucosa and/or submucosa (lymph nodes may or may not be involved)
- I Protuberant
- IIa Flat, superficially elevated
- IIb Flat, not elevated
- IIc Flat, slightly depressed
- III Excavated (full thickness of submucosa)
- Borrmann classification (gross)
- I Polypoid
- II Fungating, ulcerated with sharp raised margins
- III Ulcerated with poorly defined infiltrative margins
- IV Infiltrative, predominantly intramural lesion, poorly demarcated
- WHO classification (microscopic)
- Tubular
- Tubules and acini
- Becomes solid if poorly differentiated
- Papillary
- Fibrovascular stalks
- Mucinous
- >50% of tumor is mucin
- Poorly cohesive
- Includes signet ring
- >50% of carcinoma is composed of signet ring cells
- Includes signet ring
- Mixed
- Other types
- Adenosquamous
- Carcinoma with lymphoid stroma (medullary carcinoma)
- Hepatoid carcinoma
- Squamous carcinoma
- Undifferentiated carcinoma
- Lauren classification (microscopic)
- Intestinal type
- Cohesive, forms glands
- Associated with atrophic gastritis
- Metastasizes to nodes, liver
- Diffuse type
- Poorly cohesive, little or no gland formation
- Metastasizes to nodes, ovaries, serosa
- Mixtures of above two types
- Indeterminate
- Goseki classification (microscopic)
| Type | Tubules | Intracytoplasmic Mucin |
| I | Well differentiated | Poor |
| II | Well differentiated | Rich |
| III | Poorly differentiated | Poor |
| IV | Poorly differentiated | Rich |
- Ming classification (microscopic)
- Expanding
- Infiltrating cohesive cell aggregates
- Infiltrative
- Diffuse permeative infiltration by single noncohesive cells or individual glands
- Unclassified
- Expanding
- Special types
- Clear cell variant may be the same as pylorocardiac type
(Carr)
- Both described as having clear to pale eosinophilic cytoplasm
- Tubulo-papillary architecture
- Dysplasia ranges from minimal to severe
- Round basal or mid-level nuclei in lower grades
- Location in cardia and pylorus
- Clear cell variant has one recent description
(Ghotli)
- Clear cells make up 30-100% of cells
- Glycogen positive, rare mucin positive cells
- CK7 67%, CK20 33%
- CEA, CDX2, E cadherin (membrane), cyclin D1 100%
- AFP negative
- Pylorocardiac type reported variably as mucin positive and negative
- Not well described in recent literature
- Both described as having clear to pale eosinophilic cytoplasm
- Hepatoid
- Closely resembles hepatocellular carcinoma
- Frequently associated with intestinal type / tubulo-papillary gastric adenocarcinoma
- Trabecular, solid, pseudoglandular growth patterns
- May have canaliculi
- May have sinusoidal vessels
- Eosinophilic to clear cytoplasm
- Round to oval nuclei with prominent nucleoli
- Alpha fetoprotein is not specific and may be seen in other types
- Frequent vascular invasion and liver metastasis
- Closely resembles hepatocellular carcinoma
- Adenosquamous
- Mixture of two patterns, more than just focal
- Micropapillary
- Uncertain if behavior differs from other adenocarcinomas with lymphvascular invasion
- Carcinoma with lymphoid stroma (medullary, lymphoepithelioma)
- Most are EBV positive
- Hereditary diffuse gastric carcinoma
- Autosomal dominant, 70% penetrance
- Prophylactic gastrectomies show many foci (median 10-20) of intramucosal signet ring cells in most stomachs
- Unexpectedly low proliferation rate in the foci (<2%)
- Raises the possibility of an indolent state
- Foci primarily proximal
- Foci are infrequently found on endoscopy
- Too small to detect
- See Supplemental Studies for testing criteria
- Recently described gastric adenocarcinoma with chief cell differentiation (Ueyama 2010) appears to be better considered an adenoma (Singhi 2012)
- Clear cell variant may be the same as pylorocardiac type
(Carr)
Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342
Original posting/updates : 11/29/09, 8/21/10, 11/26/11, 12/25/12
