Umbilical Endometriosis Associated with Infraumbilical Hernia: A Case Report Highlighting Limitations of the Primary–Secondary Classification
This case report describes a 33-year-old woman with umbilical endometriosis coexisting with an infraumbilical hernia, emphasizing the diagnostic challenges of differentiating this condition from other umbilical lesions and highlighting the limitations of the traditional primary–secondary classification system.
Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer
The human body sometimes keeps a map of its own development in places where we least expect it. In a condition known as endometriosis, tissue that normally lines the inside of the uterus grows elsewhere, often causing pain and swelling that follows the monthly menstrual cycle. While this condition usually affects the pelvic area, it can occasionally appear on the abdominal wall, specifically at the navel. When this happens, it creates a tender lump that swells and aches when a woman menstruates. This specific presentation is rare and can be difficult to distinguish from other lumps, some of which are harmless and others that are serious. Because the symptoms mimic various conditions, doctors must carefully investigate to find the true cause before deciding how to treat it.
A recent report from Larkin Community Hospital details the story of a 33-year-old woman who arrived at a surgical clinic with a growing, painful lump at her navel. For several months, the mass had been getting larger, and she noticed a distinct pattern: the pain and swelling became much worse during her monthly period. Before coming to this team, she had already seen other doctors who used ultrasound and computerized tomography scans to look inside her abdomen. These images showed a small hernia, which is a weakness in the muscle wall where tissue can push through, located just below her navel. The scans also found a gallstone and a fibroid in her uterus, but they did not explain the specific nature of the painful, darkened skin on her belly button. On physical examination, the doctors felt a firm, non-reducible nodule with darkened skin over it, a sign that something unusual was happening beneath the surface.
The medical team decided to remove the lump and repair the hernia in a single operation. During the surgery, they found a small hernia sac measuring about 1 centimeter, which they repaired using a mesh to strengthen the area. They then carefully cut out the umbilical mass, taking care to separate it from the surrounding tissue without damaging the deeper layers of the abdominal wall. The removed tissue was sent to a laboratory for a close look under a microscope. The pathologists found endometrial glands and stroma, the same types of cells that line the uterus, growing inside the skin and the layer of fat just beneath it. This confirmed that the woman had umbilical endometriosis. Interestingly, the hernia sac itself did not contain any of this abnormal tissue, and the lump was confined strictly to the skin and subcutaneous layers.
After the surgery, the patient recovered without complications. Three months later, she reported that the pain was completely gone and the cyclical swelling associated with her period had stopped. The surgical site healed well, leaving a satisfactory cosmetic result. This case highlights a specific challenge in medicine: distinguishing between different types of lumps at the navel. The lump could have been a sign of a hernia, a benign growth, or even a sign of a more serious cancer, such as a Sister Mary Joseph nodule, which is a metastatic tumor. The only way to know for sure was to remove the tissue and examine it. The report also questions an old way of classifying these cases. Traditionally, doctors have labeled umbilical endometriosis as either "primary," meaning it appeared without prior surgery, or "secondary," meaning it appeared at the site of an old surgical scar. This patient had a history of a cesarean section, but the lump was at her navel, not on her scar. While this might suggest a primary case, the authors argue that this distinction does not actually change how doctors diagnose or treat the patient. The most important takeaway is that for women of reproductive age with a painful, cyclical navel lump, surgical removal is the best way to both confirm the diagnosis and cure the symptoms.
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