👉 In medicine, a pronephridiostome is a type of bladder tumor. These tumors are benign and can be found in both men and women. They usually appear as small, round, non-cancerous growths that form on or near the lower part of the bladder. The symptoms of these tumors include frequent urination, discomfort during urination, and a feeling of fullness or pressure in the abdomen or back. Pronephridiostomes can be benign (healthy)