Signet ring cell carcinoma

A usually aggressive, poorly differentiated invasive adenocarcinoma characterized by the presence of malignant glandular cells in which the nucleus is pressed to one side by the presence of intracytoplasmic mucus. It may arise from the stomach, small and large intestine, ampulla of Vater, appendix, gallbladder, pancreas, lung, bladder, breast, and prostate gland.