Stomach
Carcinoma / Adenocarcinoma
General

Author: Elliot Weisenberg, M.D. (see Authors page)

Revised: 8 December 2016, last major update August 2012

Copyright: (c) 2003-2016, PathologyOutlines.com, Inc.

PubMed Search: gastric carcinoma, gastric adenocarcinoma
Cite this page: Carcinoma / Adenocarcinoma - General. PathologyOutlines.com website. http://pathologyoutlines.com/topic/stomachcarcinomageneral.html. Accessed July 26th, 2017.
Definition / general
  • In 2012, estimated 21,320 cases in US (American Cancer Society)
  • Most gastric carcinomas are adenocarcinoma; other carcinoma types are rare
  • U.S. rates declining due to lower rates of intestinal type; rates for diffuse type unchanged
  • Worldwide, 8% of all cancers, more deaths than lung cancer, but incidence declining since 1995
  • 90% of malignant tumors in stomach are carcinomas
Epidemiology
  • High incidence in Japan, Chile, Northern Italy, China, Portugal, Russia
  • 2 / 3 men
  • Associated with lower socioeconomic groups
  • In young patients, associated with radiation therapy or chemotherapy for other malignancies
Clinical features
  • Usually asymptomatic until late
  • Symptoms: weight loss, abdominal pain, nausea, vomiting, altered bowel habits
  • Metastases to supraclavicular nodes (Virchow's node) may be first clinical manifestation
  • Sites: pylorus and antrum > cardia; lesser > greater curvature
  • Japan: mass endoscopy programs led to 35% early gastric cancers vs. 10% in US
  • Well differentiated tumors may grow very slowly (Arch Pathol Lab Med 1990;114:1046)
  • Rarely occurs in gastric stump after partial gastrectomy for ulcer (Arch Pathol Lab Med 1985;109:958)
  • Minute (< 5 mm) poorly differentiated tumors may show no gross features, however, chromoendoscopy increases their detectability (Arch Pathol Lab Med 1989;113:926)
  • Phenotypes:
    • Intestinal: majority, arise from complete type intestinal metaplasia; pattern of genetic alterations resembles colon carcinoma
    • Diffuse: arise directly from gastric foveolar epithelium, poorer prognosis
    • Microsatellite instability phenotype cancers: 10% prevalence, associated with fewer lymph node metastases, possibly improved survival (Mod Pathol 2002;15:632), minimal desmoplasia (Mod Pathol 1999;12:15); 18% with both gastric and colorectal cancers have this phenotype (Mod Pathol 2001;14:543)
Classification
  • Early: confined to mucosa or mucosa and submucosa, regardless of perigastric nodal metastases
  • Advanced: muscularis propria invasion

  • Borman classification of advanced gastric cancer:
    • Type 1, polypoid
    • Type 2, fungating
    • Type 3, Ulcerated
    • Type 4, Infiltrative

  • Lauren classification:
    • Diffuse
    • Intestinal
    • Mixed
    • Indeterminate

  • WHO classification:
    • Tubular adenocarcinoma
    • Papillary adenocarcinoma
    • Mucinous adenocarcinoma, tumor shows > 50% mucin
    • Poorly cohesive carcinomas, including signet ring cell carcinoma

  • Rare variants:
    • Adenosquamous carcinoma
    • Carcinoma with lymphoid stroma
    • Choriocarcinoma
    • Embryonal carcinoma
    • Endodermal sinus tumor
    • Hepatoid carcinoma
    • Malignant rhabdoid tumor
    • Mixed adeno-neuroendocrine carcinoma
    • Mucoepidermoid carcinoma
    • Oncocytic adenocarcinoma
    • Paneth cell carcinoma
    • Parietal cell carcinoma
    • Undifferentiated carcinoma
Prognostic factors
  • 5 year survival is 95% for surgically treated early gastric carcinoma; overall only 20% or less
  • Nodal involvement may not alter survival in early gastric cancer
  • Locally invades esophagus (proximal carcinomas), duodenum (distal carcinomas), omentum, colon, pancreas, spleen
  • Death may occur due to widespread seeding of peritoneum and lung / liver metastases
  • Also distant metastases to adrenal gland, peritoneum, ovary, spleen (#2 cause of splenic metastases, Arch Pathol Lab Med 2000;124:526)
  • Kruckenberg tumor: metastases of diffuse or signet ring types to one or both ovaries, rarely tubular pattern (Am J Surg Pathol 1981;5:225)
  • Depth of invasion most important prognostic factor
  • Poor prognostic factors: younger age (usually diffuse histology, more advanced disease), proximal half of stomach, deep invasion, infiltrative margin, diffuse histologic type, positive surgical margins (predicts local recurrence), lymph node metastases
Treatment
  • Gastrectomy, chemotherapy, trastuzumab for HER2+ tumors
Clinical images

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Virchow's Node

Cytology images

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Gastric adenocarcinoma

Negative stains
Molecular / cytogenetics description
  • c-Met: 20 - 40% in both intestinal and diffuse types
  • APC: 30 - 40% in intestinal type, < 2% in diffuse type
  • Kras: 1 - 28% in intestinal type, < 1% in diffuse type
  • HER2 / ERBB2: 5 - 15% in intestinal type, < 1% in diffuse type
  • p53: 25 - 40% in intestinal type, 0 - 21% in diffuse type