Sometimes signet-ring cell breast carcinoma is not diagnosed correctly This is true of breast cancer in general and some other cancers. It is easy to miss the diagnosis of signet ring cells in a tumor because they are very small, hidden, and often seem inconspicuous in the tissue. This is one of the reasons I helped develop some of the first over read technologies using digital mammography. For patients with lobular carcinoma, the doctors will usually have a close inspection of the lymph nodes, and pathologists can usually find signet ring cells on tissue analysis when they are associated with the disease. Signet ring cell carcinoma is a highly malignant type of cancer typically found in glandular cells that line the digestive organs. The cells resemble signet rings when examined under a microscope.