What is Melanotic Neuroectodermal Tumor of Infancy?
The Melanotic neuroectodermal tumor of infancy (MNTI) is a swiftly expanding, non-cancerous tumor that starts developing in the neural crest, an area involved in the development of nerves and skin. It typically appears in babies in the head and neck region. This tumor was first identified in 1918, and since it was initially unclear where it came from, it was referred to as a birth-related melanocarcinoma, a type of cancer.
Over time, there have been many names for it such as retinal anlage tumor, pigmented teratoma, atypical melanoblastoma, and so on. Then in 1966, two researchers named Borello and Gorlin discovered that the tumor produces a substance called vanillylmandelic acid (VMA), the same substance found in other types of tumors that come from the neural crest.
Since 1918, there have been about 500 reported cases of MNTI. The majority of cases have been reported in the United States, followed by India. The condition is slightly more common in boys. This tumor rarely spreads to other parts of the body, so the removal of the tumor through surgery is considered the best treatment. However, it’s not uncommon for the tumor to come back in the same area. While MNTI technically comes from nerve tissue (it produces VMA), most cases don’t exhibit typical characteristics of nerve tissue tumors. A recent review of jaw-related MNTI found that only 35% of cases demonstrated high levels of VMA.
What Causes Melanotic Neuroectodermal Tumor of Infancy?
Melanotic neuroectodermal tumor of infancy is a rare type of cancer that originates from cells that form our nervous system and pigment-producing cells. Scientists believe that this claim is supported by how this tumor appears under the microscope, where cells appear clustered together in a unique way.
When it comes to the genetic makeup of this rare tumor, the studies conducted so far are limited. However, some genetic changes have been identified. For instance, three cases of this tumor found in the thigh bone were seen to have a mutation known as BRAFV600E, which is usually associated with a type of skin cancer called melanoma.
Another reported case of this tumor growing in the fibula, a bone in the leg, had a few notable genetic changes, including changes in genes called CDKN2A on chromosome 9 and in a combined form of genes known as RPLP1-C19MC.
A molecular analysis of this tumor appearing again in the jawbone showed some other genetic changes similar to those seen in a kind of cancer that affects nerve tissue, called neuroblastoma. These included a loss of genetic diversity in chromosome 1p and an increase in genetic material in chromosome 7q.
All these findings point out that more research is needed to understand this tumor from a molecular and genetic point of view. This will not only help in understanding the behavior of this rare tumor better but also pave the way towards developing treatment plans that are personalized to each patient’s unique genetic makeup.
Risk Factors and Frequency for Melanotic Neuroectodermal Tumor of Infancy
MNTI, a rare type of tumor, has only had about 500 cases reported globally. It’s slightly more common in males and most cases are found in infants’ head and neck region, particularly in the upper jaw. Occasionally, it may develop elsewhere in the body. As a fast-growing tumor, it can push against nearby structures, so the preferred treatment is removal. The chance of this tumor spreading is low, but it can come back in 20% of cases.
- MNTI is a rare tumor, with only about 500 cases reported globally.
- It is slightly more prevalent in males.
- The tumor is usually located in infants’ head and neck region, especially in the upper jaw.
- In rare cases, it can develop in other parts of the body.
- MNTI grows quickly and may push against nearby structures.
- The best treatment is usually the removal of the tumor.
- The chance of the tumor spreading is about 3%.
- There’s a 20% chance of the tumor returning after treatment.
Signs and Symptoms of Melanotic Neuroectodermal Tumor of Infancy
MNTI, or Melanotic Neuroectodermal Tumor of Infancy, is a condition often seen in babies younger than 12 months. It typically shows up as a bluish lump on the face that grows quickly and is painless. Being sizeable, it can make the face look asymmetric. The lump is usually asymptomatic, meaning it doesn’t cause any discomfort or other symptoms. Frequently seen on the upper jaw and skull, the lump’s average size is around 3.5 cm, but some are much larger, even exceeding 20 cm. Boys are slightly more likely to get it, but girls older than three years can also have the condition.
Even when MNTI appears on the skull or inside the brain, it behaves much like the lumps that occur on the jaw – non-threatening. Nonetheless, symptom presentation may change depending on where the lump is located, and could include seizures, increased pressure inside the skull, and neurological issues. Beyond the head and neck, MNTI can show up in unexpected places like the ovaries, thigh bone, chest cavity, and shoulder, to name a few. While being locally aggressive and quick to grow, it very rarely (3% of cases) spreads to other parts of the body. If it does spread, the most common site is the eye socket, as indicated in a systematic review of jaw lesions.
Testing for Melanotic Neuroectodermal Tumor of Infancy
Melanotic neuroectodermal tumor of infancy (MNTI) is a rare but serious condition. If someone has a quickly growing dark-colored lump in the area of their head or neck, doctors might consider MNTI as a possible cause. Doctors look for a substance called vanillylmandelic acid (VMA) in the urine of patients when they suspect MNTI. Although it’s not always present, finding high levels of VMA can support a diagnosis of MNTI. Interestingly, research has suggested that VMA is generally only found in male patients.
To better understand the size and location of a suspected MNTI, doctors may use imaging techniques like computed tomography (CT) scans, ultrasonography, and magnetic resonance imaging (MRI). A CT scan, which creates detailed pictures of areas inside the body, can often spot MNTI because the tumors look less dense than the surrounding tissue. However, the melanin (a pigment that gives color to our skin, hair, and eyes) in the tumor will appear more dense. Large MNTI tumors can also damage nearby bones, which will show up on the scan as a “sun-burst” effect. Because of these imaging features, a CT scan can be very helpful for planning surgery to remove an MNTI tumor.
Ultrasonography, a technique that uses sound waves to create pictures of areas inside the body, has also been used in some cases. This can often show MNTI tumors as uneven, well-defined masses with less blood flow than normal.
An MRI, which uses a magnetic field and radio waves to produce detailed images of the body’s organs and tissues, usually shows MNTI tumors as an increase in signal in its images due to the presence of melanin in these tumors. Typically, however, MNTI tumors appear as dark, well-defined masses on both T1-weighted and T2-weighted images. An MRI is particularly useful in showing if the tumor has spread into the soft tissues of the body.
Finally, to confirm a diagnosis of MNTI, a doctor will take a biopsy, which is a small sample of the tumor tissue for examination under a microscope. Checking for certain markers on the tumor cells using techniques called immunohistochemical tests can help differentiate MNTI from other tumors that may look similar.
Treatment Options for Melanotic Neuroectodermal Tumor of Infancy
Treatment for MNTI, an uncommon type of tumor, is generally based on studies which have suggested that fully removing the tumor tends to be the best approach. A review of various treatment methods for MNTI in 2019 found that removal (or excision) of the tumor seems to be the most effective option, as it is associated with low chances of the tumor coming back (recurrence) and less risk of other health complications.
In some cases, patients were given a type of treatment called neoadjuvant chemotherapy before surgery. This type of treatment can potentially reduce the need for removing a large part of the tissue around the tumor during surgery, which in turn can decrease the negative impact on the patient’s appearance from the surgery.
However, even with or without additional treatments, there still tends to be a relatively high recurrence rate (around 22%) of the tumor after being removed.
In a small number of cases, MNTI was successfully treated solely with chemotherapy, without the need for any surgery. The chemotherapy drugs used to treat MNTI are similar to those used to treat neuroblastoma, another type of cancer, and include drugs like vincristine, doxorubicin, etoposide, and cyclophosphamide. However, it is important to be cautious with these treatments as one case reported a ten-year-old girl suffering from significant hearing loss after being treated with a cisplatin-based chemotherapy when she was eight months old.
Radiation therapy, which uses high-energy rays to kill cancer cells, was also sometimes used alongside surgery or chemotherapy or both. However, radiation therapy was only reported in six cases.
What else can Melanotic Neuroectodermal Tumor of Infancy be?
Diagnosing MNTI (Melanotic Neuroectodermal Tumor of Infancy), a rare tumor, can be quite tricky because the physical symptoms and microscopic features can resemble those of other types of tumors. Typically, a rapidly growing symptom-free mass is considered a sign of MNTI which helps doctors to rule out other types of tumors that usually present with other accompanying symptoms.
However, it’s important to note that the following types of tumors can initially look like MNTI and may cause confusion during diagnosis:
- Neuroblastoma: This tumor, like MNTI, also develops from neural crest cells, and can often lead to misdiagnosis. However, unlike MNTI, Neuroblastoma forms clusters of cells (rosettes) and does not contain large pigmented cells. Additionally, Neuroblastoma will not test positive for certain markers (cytokeratin, HMB-45) and lacks certain neuroendocrine markers seen in MNTI.
- Ewing Sarcoma: This type of cancer doesn’t have the varied appearance (biphasic) of MNTI and lacks melanin-containing cells that are present in MNTI. Ewing sarcoma also has its unique genetic arrangement which is not found in MNTI.
- Alveolar Rhabdomyosarcoma: Though this tumor can show up in the head and neck region, it exhibits muscular differentiation and tests positive for certain markers (desmin, myogenin). Necrosis or tissue death is also present in this tumor, which is rarely seen in MNTI.
When evaluating a pigmented mass in the head and neck, doctors should also consider the possibility of other diseases like lymphomas, malignant melanoma, and clear cell sarcoma of soft tissue.
What to expect with Melanotic Neuroectodermal Tumor of Infancy
MNTI, a type of tumor, is usually benign, or noncancerous. However, in 3% of cases, it can become malignant, or cancerous. Studies have shown that the tumor is slightly more likely to come back within five years in women than in men (25% versus 22%).
Certain factors can indicate the likelihood of the tumor coming back or becoming more dangerous:
1. Age: Tumors in infants younger than 2 months old are more likely to come back. Interestingly, tumors in children older than 12 months are associated with a 75 times higher risk of death.
2. Distant metastasis: If the cancer has spread to parts of the body away from the original tumor at the time of diagnosis, there’s a higher chance of the tumor returning and a 14 times higher risk of death.
3. Location and size: Tumors located in the lower jaw (mandible) have the highest recurrence rate (33%), followed by those in the skull (31%) and the upper jaw (maxilla, 19%). Tumors larger than 5cm are also more likely to come back.
4. Treatment method: Curettage, a surgical technique used to remove the tumor, is associated with the highest recurrence rate (61%).
5. Immunohistochemical markers: The presence of certain substances in the tumor, such as Ki-67 and CD99, although rare, can indicate that the tumor might behave more aggressively.
Possible Complications When Diagnosed with Melanotic Neuroectodermal Tumor of Infancy
MNTI, Melanotic Neuroectodermal Tumor of Infancy, is quite rare. This makes it hard to understand all the complications associated with this type of tumor. Sometimes, these tumors can grow quite quickly. This rapid growth could lead to issues like a disfigured face and destructive behavior affecting local muscles and bones. The cancer can sometimes spread to other parts of the body, but this is not common and has only been reported in a few cases.
Treatment processes also carry their risks. For instance, removing the tumor through surgery might result in local nerve and tissue damage and could cause disfigurement. Undergoing chemotherapy has its side effects too, like ototoxicity, or ear damage.
Possible complications:
- Facial disfigurement due to rapid tumor growth
- Invasion into muscles and bones
- Rare instances of cancer spreading to other parts of the body
- Nerve and tissue damage from surgery
- Potential disfigurement from surgical procedures
- Ototoxicity or ear damage as a side effect of chemotherapy
Preventing Melanotic Neuroectodermal Tumor of Infancy
It’s important to discuss with the patient’s family that there is a high chance of the disease returning after surgery. It’s also necessary to talk to them about the factors related to the initial presentation of the disease that could affect the outcome. Such conversation can help them understand the patient’s condition better and manage expectations about the recovery process.
