Atypical: In a diagnosis, the use of the term atypical is a vague warning to the physician that the pathologist is worried about something, but not worried enough to say that the patient has cancer. For instance, lymphomas (cancers of the lymph nodes) can be difficult to diagnose. Some lymph node biopsies are questionable, but do not quite fulfill the criteria for cancer. Such a case may be diagnosed as "atypical lymphoid hyperplasia." Other important atypical hyperplasias are those of the breast (atypical ductal hyperplasia and atypical lobular hyperplasia) and the lining of the uterus (atypical endometria hyperplasia). Both of these condtions are thought to be precursor warning signs that the patient is at high risk of developing cancer of the respective organ.