Thank you for sharing your concerns about a large mass behind your belly button following a tummy tuck. It's important to identify the cause of this mass for appropriate treatment. The mass could be due to several conditions: Seroma: This is an accumulation of serous fluid, a natural bodily fluid that aids in healing at surgical sites. Sometimes, the body produces an excess of this fluid, leading to the formation of a seroma. Over time, a capsule can form around this fluid collection. Hematoma: Similar to a seroma, a hematoma is a collection of blood that can occur post-surgery. It can also become encapsulated, resulting in a fluid pocket. The body eventually absorbs this fluid as the hematoma organizes into a blood clot. Hernia: Another possibility is a hernia, which involves a defect or hole in the abdominal wall. This can allow parts of the small intestine or fat to protrude through, forming a hernia. To accurately diagnose the issue, a medical evaluation is essential. This typically involves radiographic examinations, such as an ultrasound, CT scan, or MRI. These tests will help your plastic surgeon determine the exact cause of the mass and plan the appropriate course of action. Depending on the diagnosis: For a seroma or hematoma, treatment options might include needle drainage, the insertion of a drain, or surgery. If it's a hernia, surgical repair would be necessary. It's important to have this condition evaluated as soon as possible. Your healthcare provider or plastic surgeon can provide the best guidance based on the results of the diagnostic tests. I hope this information helps in understanding the potential causes of the mass behind your belly button after a tummy tuck and the importance of seeking medical evaluation for proper treatment. Good luck, and take care as you seek further medical advice. Sincerely, Dr. Katzen