What are the other Names for this Condition? (Also known as/Synonyms)

• Melanocytic Neurilemmoma
• Melanotic Neurinoma
• Pigmented Schwannoma

What is Melanotic Schwannoma? (Definition/Background Information)

• Melanotic Schwannoma is a rare tumor of the soft tissue involving the nerves of the body. It is called so, because the Schwann cells (a type of nerve cells) produce melanin pigment. The tumor is mostly found in young adults
• About half of the cases occur in individuals with Carney complex, which is an autosomal dominant genetic condition. Carney complex is characterized by the presence of multiple tumors, such as myxomas, schwannomas, and pigmented skin conditions
• The signs and symptoms of Melanotic Schwannomas are linked to the tumor site. Although most tumors are benign, some may be malignant. The malignant Melanotic Schwannomas may metastasize to various body organs (such as lung and brain)
• The treatment of Melanotic Schwannoma may involve a surgical removal of the tumor, followed by chemotherapy and radiotherapy, in case of malignant behavior
• The prognosis is excellent for benign Melanotic Schwannomas, which are not associated with Carney complex. The prognosis of Melanotic Schwannoma, if they are malignant or are associated with Carney complex, or both, can be only determined on a case-by-case basis

Who gets Melanotic Schwannoma? (Age and Sex Distribution)

• Melanotic Schwannoma is a rare tumor type that is typically observed between the age ranges of 30-40 years (young and middle-aged adults)
• It is observed in both males and females, though a slight female predominance is noted
• The tumors are seen worldwide; no known geographical, racial, or ethnic preference is noted
• Approximately 50% of the tumors occur in association with Carney complex, which is a congenital condition

What are the Risk Factors for Melanotic Schwannoma? (Predisposing Factors)

The risk factors for Melanotic Schwannoma may include:

• The presence of Carney complex; 50% of the individuals with Melanotic Schwannoma have this genetic disorder
• A family history of the tumor

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Melanotic Schwannoma? (Etiology)

The cause of Melanotic Schwannoma formation is due to genetic mutations.

• Abnormalities in chromosome 2 is observed with additions/deletions in 2p16 region. Such changes are seen in 4 out of 5 tumors
• Involvement of the CNC2 gene is noted
• The mutations are seen in both syndromic (familial) type and non-syndromic (sporadic) type
• Carney complex is caused by defective genes and is inherited in an autosomal dominant manner

What are the Signs and Symptoms of Melanotic Schwannoma?

In some cases, Melanotic Schwannoma may not present any signs and symptoms. In tumors with signs and symptoms, it may be dependent upon the location of the tumor and its association with Carney complex.

The signs and symptoms of Melanotic Schwannoma may include:

• Pain and mass effect of large tumors causing compression of the adjoining structures may be noted
• Since the nerves are affected, altered sensations may be observed. The part of the body involved (i.e., showing signs and symptoms), depends on the specific nerve that is affected
• 50% of the tumors occur in the spinal nerves and paraspinal ganglia. Cervical and thoracic spinal nerves are more commonly involved than lumbar and sacral spinal nerves
• The second most common site of involvement is the autonomic nerves of gastrointestinal (GI) tract
• The tumors occur as a firm mass and are mostly solitary, though sometimes, multiple tumors are observed, typically in the context of Carney complex

Signs and symptoms of underlying Carney complex may be observed in individuals with Melanotic Schwannoma.

How is Melanotic Schwannoma Diagnosed?

A diagnosis of Melanotic Schwannoma is made using the following tools:

• Complete physical examination with thorough evaluation of the individual’s medical history (including history of Carney complex)
• Neurological exam of the entire body
• Radiological studies (CT, MRI scan) of the affected region
• Nerve conduction studies of the affected nerve
• Other specific tests may be conducted based on the location of the tumor
• Tissue biopsy: A tissue biopsy is performed and sent to a laboratory for a pathological examination, who examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis

Note: Up to 50% of the tumors have psammoma bodies, which can be observed by a pathologist under the microscope. Such tumors are called psammomatous Melanotic Schwannoma (PMS).

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Melanotic Schwannoma?

The complications of Melanotic Schwannoma depend on where the tumors are located and may include:

• Compression of the underlying nerve, which can severely affect the nerve function
• Damage to the nerve or organ during surgery to remove the tumor
• Tumors can cause eroding of the surrounding bone
• Melanotic Schwannoma may be malignant and metastasize to various organs, such as the lung, brain, stomach, liver, adrenal gland
• If the focus of metastasis is large, then it can cause liver and adrenal gland function abnormalities
• Infrequently, recurrence of the tumor after surgery, if the tumor is incompletely removed
• Complications of Carney complex

How is Melanotic Schwannoma Treated?

Treatment measures for Melanotic Schwannoma may include the following:

• In many cases of benign tumors not related to Carney complex and if no symptoms are observed, no treatment may be necessary. Periodic observations can be maintained through regular check-ups
• Treatment of the underlying Carney complex
• Complete surgical excision and removal of the tumor is the preferred treatment option; surgical excision for benign tumors may be undertaken, when required
• Malignant tumors can be treated with a combination of surgery, chemotherapy, and radiation therapy, depending on the location of the tumor
• Post-operative care is important: One must maintain minimum activity levels, until the surgical wound heals
• Follow-up care with regular screening and check-ups are important and encouraged

How can Melanotic Schwannoma be Prevented?

Current medical research has not established a method of preventing Melanotic Schwannoma. However, for those tumors that occur with Carney complex, the following measures may be considered:

• Genetic testing of the expecting parents (and related family members) and prenatal diagnosis (molecular testing of the fetus during pregnancy) may help in understanding the risks better during pregnancy
• If there is a family history of the condition, then genetic counseling will help assess risks, before planning for a child
• If an individual is diagnosed with Carney Complex, then it is important to screen close blood relatives of the patient too

Active research is currently being performed to explore the possibilities for treatment and prevention of inherited and acquired genetic disorders.

What is the Prognosis of Melanotic Schwannoma? (Outcomes/Resolutions)

• The prognosis of Melanotic Schwannoma is excellent, if the tumors are benign and do not arise in association with Carney complex. In such cases, a surgical removal of the tumor is curative
• The prognosis of malignant tumors depends on their stage including whether they have metastasized to other body regions or organs
• Syndromic tumors associated with Carney complex have higher chances of metastasis. Both non-psammomatous and psammomatous tumors are known to metastasize
• The prognosis of Melanotic Schwannoma when it is associated with Carney complex, depend upon the signs and symptoms of underlying disorder. The outcome of Carney Complex depends upon the location and type of tumors and the combination of signs and symptoms

Additional and Relevant Useful Information for Melanotic Schwannoma:

From a biopsy specimen, it is very hard to differentiate between a benign or malignant Melanotic Schwannoma, and hence, work-up of the patient for metastasis is very important. A definite indication of malignancy is the presence of metastasis of the tumor.