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

• Perineurial Malignant Peripheral Nerve Sheath Tumor
• Perineurial MPNST

What is Malignant Perineurioma? (Definition/Background Information)

• A Malignant Perineurioma is a malignant tumor of the perineurial cells. A Perineurioma is a rare tumor of the perineurial cells, a type of cells that are present around a peripheral nerve sheath
• These tumors are generally benign in nature, but may be occasionally malignant. Perineuriomas can occur at a superficial location (underneath the skin), or they may be deep-seated (affecting various internal organs)
• There are 3 different types of Perineuriomas, namely:
  • Intraneural Perineurioma: The tumor grows along the nerve; most commonly in the peripheral nerves of the arms and legs
  • Soft Tissue Perineurioma: When the tumor does not grow along the nerve, but instead, grows into the soft tissues surrounding a nerve, they are called Soft Tissue Perineuriomas. These tumors may be present at any location in the body
  • Malignant Perineurioma: It is the malignant transformation of a Perineurioma that can either be the intraneural type or soft tissue type
• There are no identified risk factors or causative factors for Malignant Perineurioma, though certain chromosomal abnormalities have been observed
• The signs and symptoms of Malignant Perineurioma are dependent upon the location of the tumor. They may develop in the soft tissues or the nerves of the body
• A combination of chemotherapy, radiation therapy, and surgical procedures may be used to treat Malignant Perineuriomas. The outcome for an individual with this tumor is guarded, due to its capacity to metastasize and recur

Who gets Malignant Perineurioma? (Age and Sex Distribution)

• Malignant Perineurioma can affect both adults and children (adolescents)
• Both males and females are affected
• There is no known racial, ethnic, or geographical preference

What are the Risk Factors for Malignant Perineurioma? (Predisposing Factors)

• The risk factors for Malignant Perineurioma are currently unknown or unidentified

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 Malignant Perineurioma? (Etiology)

• The exact cause and mechanism of formation of Malignant Perineurioma is unknown
• They arise from either soft tissue perineurioma or intraneural perineurioma (malignant transformation)
• Studies have shown chromosomal abnormalities on chromosome 22 (monosomy of chromosome 22), which may be responsible for the development of a perineurioma

What are the Signs and Symptoms of Malignant Perineurioma?

The signs and symptoms of Malignant Perineurioma depend upon the type of perineurioma it evolved from and the location of the tumor.

• If it developed from a soft tissue perineurioma, the following may be seen:
  • The presence of small, solitary tumors that do not cause any significant signs and symptoms
• If it developed from an intraneural perineurioma, the following may be seen:
  • Enlargement of the affected nerve
  • Muscle weakness in the affected muscle
• The tumors may form anywhere in the body
• Pain in the affected region
• In many individuals, loss of weight and appetite, and fatigue is observed. However, these symptoms appear later, as the cancer progresses

How is Malignant Perineurioma Diagnosed?

A diagnosis of Malignant Perineurioma may involve the following steps:

• Complete physical examination and comprehensive evaluation of individual’s medical history
• CT or MRI scan of the affected region to aid in obtaining a clear image of the tumor, prior to surgery
• 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 may arrive at a diagnosis
• Molecular analysis to exclude other tumors
• If tumor has metastasized (into the lungs or other regions) then PET scan, bone scan, and chest x-rays may be taken

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 Malignant Perineurioma?

The complications of Malignant Perineurioma may include:

• Metastasis to the bones, lungs, or lymph nodes
• Damage of vital nerves, blood vessels, and surrounding structures, during surgery to remove the tumor
• Side effects from chemotherapy (toxicity), radiation therapy
• Recurrence of the tumor in case of incomplete excision and removal

How is Malignant Perineurioma Treated?

The treatment of Malignant Perineurioma may be undertaken as:

• Any combination of chemotherapy, radiation therapy, and invasive procedures may be used to treat the tumors
• Embolization is used to provide temporary relief from the symptoms, and reduce blood loss during a surgical procedure
• Wide surgical excision and removal of the entire tumor, followed by radiation therapy (or chemotherapy) is the standard treatment mode
• 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 Malignant Perineurioma be Prevented?

• Current medical research have not established a way of preventing Malignant Perineurioma
• Regular medical screening at periodic intervals with blood tests, scans, and physical examinations, are mandatory, due to its metastasizing potential and possibility of recurrence. Often several years of active vigilance is necessary

What is the Prognosis of Malignant Perineurioma? (Outcomes/Resolutions)

• The prognosis of Malignant Perineurioma depends upon the stage of the tumor, the location of the tumor, and the age and health of the individual
• Early diagnosis and treatment generally yields a better prognosis and is important

Additional and Relevant Useful Information for Malignant Perineurioma:

A differential diagnosis may be considered to eliminate the following conditions:

• Neurofibroma
• Dermatofibroma
• Neurothekeoma