Lymph nodes filter substances that travel through the lymphatic fluid, and they contain lymphocytes (white blood cells) that help the body fight infection and disease. There are hundreds of lymph nodes found throughout the body. The perirectal lymph nodes are located around the rectum and drain parts of the colon and the upper part of the rectum. Sometimes lymph nodes are noted on imaging to be prominent (enlarged). Anything that causes inflammation can cause enlarged lymph nodes, including viral and bacterial infections. Usually enlarged lymph nodes do not cause symptoms, are self-resolving and do not need any further follow-up. If symptoms are present they could include abdominal/pelvic pain and/or weight loss.
Small amounts of free fluid in the pelvis is a normal finding in healthy men without symptoms (e.g. abdominal/pelvic pain) or known abdominal/pelvic disease. However, small amounts of free fluid in the pelvis can also be present in men with known abdominal/pelvic conditions such as abdominal/pelvic infections, inflammation of the inner abdominal wall lining (peritonitis), liver cirrhosis and cancer.
Small amounts of free fluid in the pelvis is a normal finding in pre- and post-menopausal women without symptoms or known abdominal/pelvic disease. However, larger amounts of free fluid can be due to a pathological process including bleeding into the stomach, trauma, acute inflammation, rigorous exercise (e.g. running a marathon), and gastritis.
Lipomas are the most common type of fat-containing, benign (non-cancerous) growths and demonstrate a characteristic appearance on MRI. The cause is not fully understood, but there is a genetic factor as they typically run in families. Usually lipomas do not cause symptoms, but can become painful if large and pressing on nearby nerves.
A pelvic kidney is when one or both kidneys stay in the pelvis and do not move into their proper position during fetal development. A normal variant is an atypical finding that is seen but has no clinical significance, and is considered within the spectrum of normal findings.
Pelvic varices are caused by venous obstruction, increased pressure, and venous insufficiency, resulting in dilated (enlarged) and/or misshapen veins. They can arise in isolation, in association with leg/buttock or scrotal varices (varicocele), or as part of pelvic congestion syndrome (a condition that causes chronic pelvic pain).
