Melanoma is a type of cancer that originates in the melanocytes, the pigment-producing cells of the skin. While complex, the answer to whether a person can be born with this disease is yes, though it is exceptionally rare. True congenital melanoma is an extremely infrequent pediatric diagnosis, differing significantly from the far more common benign birthmarks that contain melanocytes. Understanding this distinction is important, as this serious malignancy requires specialized medical attention immediately after birth.
The Reality of Congenital Melanoma
Congenital melanoma is medically defined as a malignant tumor of melanocytes present at birth or diagnosed within the first year of life. This diagnosis is distinct from melanoma developing later in childhood or adulthood. Compared to adult melanoma, the incidence of melanoma in children is low, occurring in approximately 0.7 cases per million children aged 0–9 years.
True cases of melanoma present at birth are exceedingly uncommon, representing a tiny fraction of all childhood cancers. When the disease is present in a newborn, it typically follows an aggressive course and is often associated with a challenging prognosis. The presentation is typically classified as either a primary tumor that developed in utero or, in the rarest of circumstances, a metastatic tumor that spread from the mother.
The aggressive behavior of congenital melanoma often leads to a poor outcome despite immediate intervention. Because of its rarity and rapid nature, congenital melanoma necessitates immediate, specialized medical care.
Distinguishing Melanoma from Common Birthmarks
The vast majority of pigmented lesions present at birth are not cancerous but are instead a type of benign growth called a congenital melanocytic nevus (CMN). CMNs, commonly known as birthmarks or moles, are found in about one percent of all newborns worldwide. These spots are abnormal collections of melanocytes in the skin and are not considered cancer at the time of birth.
Congenital melanocytic nevi are typically brown or black patches that vary widely in size and may develop coarse hair over time. The primary concern with CMNs is that large or giant lesions (projected to be greater than 20 centimeters in diameter in an adult) carry an increased lifetime risk of eventually transforming into melanoma. This malignant transformation typically occurs later in childhood, not at birth.
A true congenital melanoma often presents with alarming characteristics that differentiate it from a benign nevus. Clinical signs indicating a malignant process include rapid growth, ulceration, or bleeding of the lesion, and highly irregular or unusual coloring. Melanoma arising in a nevus often presents as a new, firm, or raised nodule developing within the existing lesion, frequently in the deeper tissue layers.
Potential Causes and Risk Factors
The development of melanoma in a newborn can be attributed to one of two extremely rare biological pathways. The first and most common pathway for primary congenital melanoma involves a spontaneous genetic mutation that arises during fetal development. These somatic mutations often involve genes in the mitogen-activated protein kinase (MAPK) pathway, such as NRAS or BRAF.
These mutations cause the melanocytes to proliferate abnormally in utero, resulting in tumor formation. The largest risk factor for a child developing melanoma is the presence of a large or giant congenital melanocytic nevus. The nevus itself is caused by a similar genetic error early in development, placing the child at a higher risk for a second, cancerous mutation within the same area of skin.
The second pathway for congenital melanoma is transplacental metastasis, where cancer cells from a mother with metastatic melanoma cross the placenta to the fetus. Melanoma is the cancer most frequently associated with this type of maternal-fetal spread. If the mother’s placenta contains melanoma cells, the risk of the cancer spreading to the fetus is estimated to be around 22 percent.
Diagnosis and Management in Infants
Once a suspicious pigmented lesion is identified on a newborn, medical professionals initiate a thorough diagnostic workup. The definitive diagnosis of melanoma requires a biopsy, often involving the surgical removal of the entire lesion for pathological examination. This procedure determines the depth and stage of the tumor.
Imaging studies are routinely performed to check for any spread of the disease, particularly to the central nervous system. Infants born with multiple or very large congenital melanocytic nevi may undergo a screening Magnetic Resonance Imaging (MRI) scan to detect neurocutaneous melanosis. This condition involves melanocytes present in the brain and spinal cord, which significantly increases the risk of melanoma development in those areas.
The primary management strategy for confirmed congenital melanoma is prompt and complete surgical excision of the tumor. Given the aggressive nature of the disease in newborns, the procedure may be followed by a lymph node evaluation to check for local spread. The prognosis for infants diagnosed with primary congenital melanoma is often guarded, as the disease frequently behaves more aggressively than adult melanoma, underscoring the importance of early detection and specialized pediatric oncology care.