Are there different types of stomach cancer?

Yes, there are a few different types of stomach cancer, but the vast majority—90 percent—are adenocarcinomas. These tumors develop from the cells that form the innermost layer of the stomach, called the mucosa. In some cases, it can spread (metastasize) throughout the stomach, penetrate the wall and progress to the adjacent lymph nodes and other organs. One form of adenocarcinoma is linitus plastica or diffuse gastric cancer often involving most of the stomach

The other, less common tumors that can be found in the stomach are:

• Lymphomas - cancers of immune system tissue
• Gastrointestinal stromal tumors (GIST) - can be benign or cancerous
• Carcinoid tumors - come from hormone-producing cells in the stomach
• Leimyosarcoma - cancer of the soft tissue 

These types of stomach cancer are very rare and their treatment and prognosis differ from adenocarcinomas.