Each patient is different. Without a detailed history, physical exam, and supportive diagnostic tests, it is impossible to specifically answer your question. There are a number of genetic conditions in which the fallopian tube either does not develop or develops abnormally. However, it is highly unlikely that a fallopian tube would “disappear” over the course of one year. The best person to answer the question would be your gynecologist, a fertility expert, or the gynecologic surgeon who took you for your operation one year ago to remove the uterine mass.