Gastric cancer is one of the most important diseases that endangers people's health. Beside gastric adenocarcinoma, gastric carcinoma also includes the following types: adenosquamous carcinoma, squamous carcinoma, gastric neuroendocrine tumor, gastric hepatoid adenocarcinoma, AFP-producing gastric cancer, EBV-associated gastric cancer, lymphoepithelioma-like carcinoma, undifferentiated-type gastric cancer, gastric carcinosarcoma and so on. The adenosquamous carcinoma, squamous carcinoma of stomach, gastric hepatoid adenocarcinoma, AFP-producing gastric cancer and gastric carcinosarcoma mainly occurred in old men, while the linitisplastica gastric cancer was common in young women. It refers to the gastric cancers that are clinically rare and have lower incidence, unique histological and pathological features, however, without obviously clinical manifestations. The clinically uncommon gastric cancers are easy to be misdiagnosed or missed, and further to miss the optimal opportunity for treatment due to the unclearly specific pathogenesis and disease progression. With the development of studies on the clinically uncommon gastric carcinoma, although people have a further knowledge of its pathologic features, methods of diagnosis and treatment, the diagnosis and treatment standards for the clinically uncommon gastric cancer has not yet been established and unified. The therapeutic principle of the clinically uncommon gastric cancers is also the radical surgery, radiotherapy and chemotherapy as the main comprehensive treatment supplemented by individualized treatment. With lucubrating the pathogenesis of them, specific diagnostic methods and treatment measures are new hope for improving the diagnosis and treatment of the clinically uncommon gastric cancers. So, the further researches on the clinically uncommon gastric cancers and exploring their etiology, pathogenesis, histological and pathological features have important significance to their diagnosis and treatment. This article makes a summary of the clinically uncommon gastric cancers with the aspects of epidemiology, histology, pathology, diagnosis, treatment, to provide reference to clinical diagnosis and scientific studies.