An autosomal dominant inherited adenocarcinoma that arises from the gastric mucosa and is characterized by the presence of poorly cohesive malignant cells and absence of glandular formations. The disease is Monarch Disease Ontology id MONDO_0007648 (hereditary diffuse gastric adenocarcinoma). Also known as: FDGC, HDGC, familial diffuse cancer of stomach, familial diffuse gastric cancer, hereditary diffuse cancer of stomach, hereditary diffuse gastric cancer.