What Is a Malignant Peripheral Nerve Sheath Tumor?

Malignant schwannoma is a rare tumor of the peripheral nervous system and originates from Schwann cells, so it is also called malignant Schwann's cell tumor. This tumor mostly occurs in young and middle-aged men, and it usually occurs in the limbs or scalp and neck. Tumors grow slowly, usually over 5 years, often accompanied by neurofibromas or schwannomas. About two-thirds of the cases are based on the recurrence and malignancy of these two diseases. It can occur in any part of the body, and its symptoms are diverse and lack specificity. It is more common in the limbs and trunk, and sciatic nerve involvement is common. Locally found masses are common symptoms, most of which are painless, and a few are painful masses, or symptoms of mass compression, numbness of distant limbs, and radiation pain. Tumors have also been reported in the skull, ovaries and cervix. Tumors can invade locally, and distant lymph nodes and blood circulation metastasis can also occur.

Malignant schwannoma is a rare tumor of the peripheral nervous system and originates from Schwann cells, so it is also called malignant Schwann's cell tumor. This tumor mostly occurs in young and middle-aged men, and it usually occurs in the limbs or scalp and neck. Tumors grow slowly, usually over 5 years, often accompanied by neurofibromas or schwannomas. About two-thirds of the cases are based on the recurrence and malignancy of these two diseases. It can occur in any part of the body, and its symptoms are diverse and lack specificity. It is more common in the limbs and trunk, and sciatic nerve involvement is common. Locally found masses are common symptoms, most of which are painless, and a few are painful masses, or symptoms of mass compression, numbness of distant limbs, and radiation pain. Tumors have also been reported in the skull, ovaries and cervix. Tumors can invade locally, and distant lymph nodes and blood circulation metastasis can also occur.

Chinese name

Malignant schwannoma

Foreign name

malignant schwannoma

Malignant schwannoma I. Causes and common diseases:

This disease is caused by aberrant genes in the neuroectodermal abnormalities, leading to multiple tumor-like hyperplasia of peripheral nerves and proliferation of connective tissue in nerve sheaths and nerve fibers.

Malignant schwannoma II. Differential diagnosis:

This tumor line consists of malignant nerve sheath cells and nerve membrane cells. The envelope is often incomplete, and most of them are infiltrated by tumor cells. Tumor cells are spindle-shaped, invasively growing, arranged in interlaced strands, sometimes feather-like, occasionally palisade-like or reticular, with bleeding and necrosis. The nuclei of tumor cells are oval or spindle-shaped, some of them are polygonal in shape, different in size, and have obvious atypia. Sometimes giant or multiple nuclei are seen. Nuclear mitosis is more common.

It should be distinguished from the following diseases: (1) Fibrosarcoma, often without capsule, less bleeding and necrosis. Tumor cell nuclei are slightly pointed at both ends, and there are more collagen fibers in cytoplasm and interstitial. (2) Leiomyosarcoma, which contains myofibrils in the tumor cells, stains PTAH in purple blue, and tricolor stains red.

Malignant schwannoma III. Examination:

(1) Physical examination:

Masses are a common symptom, mostly painless, and difficult to distinguish from other sarcomas. Some manifested as painful masses, or numbness and radiating pain in distant limbs due to mass compression. Deep tumors show corresponding symptoms due to local invasion, such as chest pain, belching (rear mediastinum), lumbar and leg pain (injury of lumbar spinal nerve roots), diplopia (invasion of eyeballs), and so on. Others may be asymptomatic and a lump may be found on physical examination.

(Two) X films:

X-rays show that some tumors have calcification and sometimes secondary bone destruction.

(Three) ultrasound and CT examination:

The relationship between the tumor range and surrounding tissues can be observed, and the diagnosis depends on pathological examination.

Malignant schwannoma IV. Principles of treatment:

(A) surgical resection:

Surgical resection is the most effective treatment. However, the treatment of malignant schwannoma is slightly different from other soft tissue tumors. Because the tumor originates from the neural trunk and involves a section of nerve tissue, it is difficult to determine the edge of the tumor. During surgery, frozen sections should be performed on the upper and lower resection margins of the involved nerve segment. Extensive resection of low-grade malignant superficial tumors can be cured. High-malignant tumors involving large nerve trunks may sacrifice this nerve or amputate. Tumors with external irradiation alone are often insensitive and require increased radiation doses, which have large side effects.

(2) Chemoradiation check:

Tumors are not sensitive to external irradiation alone, and often require increased doses. The efficacy of chemotherapy is not certain. Some reports suggest that it can reduce local recurrence and control distant metastases.