Primitive neuroectodermal tumor
WikiDoc Resources for Primitive neuroectodermal tumor
Evidence Based Medicine
Guidelines / Policies / Govt
Patient Resources / Community
Healthcare Provider Resources
Continuing Medical Education (CME)
Experimental / Informatics
Synonyms and Keywords: Primitive neuroectodermal tumors; PNET; CNS PNET; Askin tumor; Peripheral neuroepithelioma; Ependymoblastoma
Primitive neuroectodermal tumor (also known as "PNET") is a rare type of malignant neural crest tumor. Primitive neuroectodermal tumor arises from the neuroectoderm, which is normally involved in the development of the nervous system. Primitive neuroectodermal tumor was first discovered by James Ewing, an American pathologist, in 1921. Primitive neuroectodermal tumors are more commonly seen among children and young adults . The median age at diagnosis is 25 years of age. Prognosis is generally poor, and the 5-survival rate of patients with primitive neuroectodermal tumor is approximately 53%.
- Primitive neuroectodermal tumor was first discovered by James Ewing, an American pathologist, in 1921.
- Primitive neuroectodermal tumor may be classified according to World Health Organization into 3 subtypes:
- Central primitive neuroectodermal tumors (PNETs)
- Peripheral primitive neuroectodermal tumors (pPNETs)
- Primitive neuroectodermal tumor is composed of primitive undifferentiated neuroepithelial cells.
- Primitive neuroectodermal tumors are intracranial and usually located in the cerebral hemisphere.
- The EWS-like gene has been associated with the development of primitive neuroectodermal tumor.
- On gross pathology, characteristic findings of primitive neuroectodermal tumor, include:
- Cystic components
- On microscopic histopathological analysis, characteristic findings of primitive neuroectodermal tumor, include:
- Small blue cell tumor
- Round hyperchromatic cells
- Abundant mitotic figures
- Homer Wright rosettes
- There are no established causes for primitive neuroectodermal tumor.
Differentiating Primitive Neuroectodermal Tumor from Other Diseases
- Primitive neuroectodermal tumor must be differentiated from other diseases that cause seizures, or increase on intracranial pressure, such as:
- Intracranial teratoma
Epidemiology and Demographics
- The prevalence of primitive neuroectodermal tumor remains unknown.
- Primitive neuroectodermal tumor account for 4-17% of all soft tissue paediatric tumors.
- The median age at diagnosis is 25 years old.
- Primitive neuroectodermal tumor is more commonly observed among children and young adults.
- Primitive neuroectodermal tumor affects men and women equally.
- There is no racial predilection for primitive neuroectodermal tumor.
- Common risk factors in the development of primitive neuroectodermal tumor, include:
Natural History, Complications and Prognosis
- The majority of patients with primitive neuroectodermal tumor remain asymptomatic for years.
- Early clinical features are often unspecific.
- If left untreated, patients with primitive neuroectodermal tumor may progress to develop
- Common complications of primitive neuroectodermal tumor, include:
- Increased intracranial pressure
- Cranial nerve palsy
- Prognosis is generally poor, and the 5-survival rate of patients with primitive neuroectodermal tumor is approximately 53%.
- Clinical presentation of primitive neuroectodermal tumors is often non-specific.
- Symptoms of primitive neuroectodermal tumor may include the following:
- Obtain medical history, on the following syndromes:
- Gorlin-Goltz syndrome
- Turcot syndrome
- Patients with primitive neuroectodermal tumor usually are
- Physical examination may be remarkable for:
- There are no specific laboratory findings associated with primitive neuroectodermal tumor.
- MRI is the imaging modality of choice for primitive neuroectodermal tumor.
- On CT, findings of primitive neuroectodermal tumor, may include:
- Often seen as a large irregular mass
- Typically iso to hyper-attenuating on non contrast imaging
- Cystic components are common (65%)
- Calcification can be common (70% )
- Shows heterogenous contrast enhancement
- On MRI, findings of primitive neuroectodermal tumor, may include:
- T1: highly variable and can be hypointense to isointense
- T2: generally high signal solid components
- Cystic components are common
- Low signal portions due to calcific components
- T1 C+ (Gd): shows markedly heterogenous enhancement and leptomeningeal seeding is common
- DWI: often shows restricted diffusion
- MR spectroscopy: elevated choline, decreased NAA, elevated taurine (Tau) peak (relatively specific for PNET).
- There is no treatment for primitive neuroectodermal tumor; the mainstay of therapy is supportive care.
- Surgery is the mainstay of therapy for primitive neuroectodermal tumor.
- There are no primary preventive measures available for primitive neuroectodermal tumor.
- James Ewing. https://en.wikipedia.org/wiki/James_Ewing_(pathologist) Accessed on May 20, 2016
- PNET. Wikipedia. https://en.wikipedia.org/wiki/Primitive_neuroectodermal_tumor Acceded on May 23, 2016