Peripheral primitive neuroectodermal tumor

Peripheral primitive neuroectodermal tumor (PNET) is a rare and highly malignant neoplasm that predominantly affects children and young adults. It is a member of the Ewing sarcoma family of tumors, which also includes Ewing sarcoma of bone and Askin tumor.

Etiology

The exact cause of PNET is unknown. However, it is believed to originate from neural crest cells, which are primitive cells that can develop into a variety of cell types. Most PNETs are associated with a specific chromosomal translocation, t(11;22)(q24;q12), which results in a fusion gene, EWS-FLI1. This fusion gene is believed to play a key role in the development of the tumor.

Clinical Presentation

Patients with PNET typically present with a rapidly growing mass. The tumor can occur anywhere in the body, but it is most commonly found in the chest, abdomen, pelvis, and extremities. Symptoms depend on the location of the tumor and may include pain, swelling, and functional impairment. Systemic symptoms such as fever, weight loss, and malaise may also be present.

Diagnosis

Diagnosis of PNET is based on histological examination of the tumor. The tumor cells are small, round, and blue, with high mitotic activity. Immunohistochemical staining is typically positive for neuron-specific enolase, CD99, and FLI-1. Molecular genetic testing can confirm the presence of the EWS-FLI1 fusion gene.

Treatment

Treatment of PNET typically involves a combination of surgery, chemotherapy, and radiation therapy. The goal of treatment is to remove or destroy the tumor and prevent metastasis. Despite aggressive treatment, the prognosis for patients with PNET is poor, with a 5-year survival rate of less than 50%.

See Also

• Ewing sarcoma
• Neoplasm
• Chemotherapy
• Radiation therapy