Schwannomas are tumors that arise in the Schwann cells found in the sheaths that surround nerves. Oftentimes, schwannomas are benign, but can still cause serious medical problems. The acoustic neuroma, for instance, which is the most common variety of benign schwannoma, can result in deafness because it occurs on the cranial nerve associated with hearing.

Similarly, other symptoms that arise from schwannomas are often related to the loss of function of the nerve they affect, but the tumors may also simply manifest themselves in the form of pain or may be asymptomatic. Schwannomas can develop anywhere in the body where Schwann cells are present, but most commonly occur in nerves in the lower back, upper arms, or legs.

Malignant schwannomas are rare and are classified among the soft tissue sarcomas, accounting for about ten percent of all such tumors diagnosed. Individuals between 20 and 50 years of age are more likely to develop malignant schwannomas than children or the elderly, but the tumors can appear at any age. Notably, when associated with the autosomal dominant genetic disorders neurofibromatosis I and II, onset is typically many years earlier than the average onset age. About 50 percent of malignant schwannomas are linked to one of these disorders.

Similar to most other types of cancers, malignant schwannomas are generally treated with one or more of the following: surgery, chemotherapy, or radiotherapy. The five-year survival rate associated with malignant schwannomas is low, primarily due to poor response of the tumors to available treatments and metastasis to the lungs and other areas of the body. Patients that usually have the best outlook are those that are young and have relatively small tumors able to be completely removed via surgical means.

Malignant Schwannoma at 10x Magnification - Malignant schwannomas are often alternatively referred to as neurofibrosarcomas or malignant peripheral nerve sheath tumors.

Malignant Schwannoma at 20x Magnification - Malignant schwannomas can be difficult to diagnose, and are usually more than 5 centimeters in diameter by the time they are brought to the attention of a medical professional and identified.