Cancer can occur in the belly button, or umbilicus, though it is an exceptionally rare event. The umbilicus is the remnant of the umbilical cord, composed of skin, underlying fat, and fibrous tissue connected to the abdominal wall. When cancer appears here, it is far more likely to have spread from a distant internal organ than to have started there. This distinction defines the approach to diagnosis and treatment.
The Difference Between Primary and Metastatic Navel Cancer
Understanding cancer in the navel requires classifying it into two categories based on its origin. Primary umbilical cancer arises directly from the cells within the skin or underlying tissues of the umbilicus itself. These cases are exceedingly uncommon, representing only a small fraction of all umbilical tumors.
Metastatic umbilical cancer describes a tumor that began elsewhere in the body and then traveled to the navel through metastasis. This makes up the vast majority of cancer cases found in the umbilicus. A cancerous lesion discovered in the belly button often signals a more advanced, underlying internal malignancy, fundamentally changing the medical evaluation and treatment plan.
Cancers That Start in the Umbilicus
Primary cancers of the umbilicus originate in the skin cells and are generally categorized as skin cancers. The most frequent types include Basal Cell Carcinoma (BCC), Squamous Cell Carcinoma (SCC), and Melanoma. These tumors are usually seen on skin that has been chronically irritated or inflamed, which can occur in the deep folds of the umbilicus.
Basal Cell Carcinoma is exceptionally rare in the navel, a non-sun-exposed site, but can develop from the basal cells of the epidermis. Melanoma, a malignancy of the pigment-producing melanocytes, is also found occasionally and carries a high potential for spread if not detected early. Tumors may also arise from remnants of embryonic structures, such as adenocarcinoma from a vestigial urachal element, though these are less common than primary skin cancers.
When Internal Cancers Spread to the Navel
The most common presentation of malignancy in the navel is a metastatic lesion, often called a Sister Mary Joseph Nodule (SMJN). This nodule represents cancer spread from an internal primary site, typically within the abdomen or pelvis. The most frequent primary sources for SMJN are cancers of the gastrointestinal tract, including the stomach, colon, and pancreas.
In female patients, gynecological malignancies, particularly ovarian cancer, are a significant source of umbilical metastasis. Cancer cells are hypothesized to reach the umbilicus through several potential pathways.
Pathways of Metastasis
- Direct spread across the peritoneal lining of the abdomen.
- Travel through the lymphatic vessels that run alongside the obliterated umbilical vein.
- Spread through blood circulation.
The umbilicus contains remnants of fetal circulatory and ductal structures, such as the vitelline duct and the umbilical ligaments, which may serve as conduits for tumor cells to seed the area.
Recognizing Signs and Confirming Diagnosis
Recognizing a malignant umbilical lesion begins with a noticeable change in the area. A primary skin cancer may appear as a non-healing sore, a rapidly changing mole, or a pearly, translucent bump, similar to skin cancers elsewhere. A metastatic Sister Mary Joseph Nodule typically presents as a firm, irregular, and sometimes painful mass protruding from the navel. This nodule can be accompanied by ulceration or discharge, which may be clear, bloody, or purulent.
The diagnostic process starts with a thorough physical examination and a detailed review of the patient’s medical history. Confirmation of malignancy requires a biopsy, where a small tissue sample is removed from the lesion and examined under a microscope. If the biopsy confirms a metastatic tumor, imaging studies, such as CT or PET scans, are used to locate the primary cancer site within the abdomen or pelvis. Identifying the origin is crucial because treatment targets the primary tumor, not just the visible nodule.
Management and Treatment Options
The approach to managing cancer in the navel depends entirely on whether the tumor is primary or metastatic. For a primary umbilical skin cancer, such as Basal Cell Carcinoma or Melanoma, treatment is usually localized surgical excision. The goal of this surgery is to remove the entire tumor along with a margin of healthy tissue to prevent recurrence.
In cases of metastatic cancer, the Sister Mary Joseph Nodule signals advanced, systemic disease, often classified as Stage IV. Treatment for SMJN focuses on the underlying primary malignancy and typically involves systemic therapies like chemotherapy, targeted therapy, or immunotherapy. Surgical removal of the nodule is generally considered a palliative measure to relieve symptoms, as the spread indicates a poor prognosis.