obsolete primitive neuroectodermal tumor with Leptomeningeal Spread

Primitive Neuroectodermal Tumor (PNET) with Leptomeningeal Spread

Primitive neuroectodermal tumors (PNETs) are a type of rare and highly aggressive brain cancer that primarily affects children and young adults. One of the less common manifestations of PNET is its spread to the leptomeninges, which are the protective membranes surrounding the brain and spinal cord.

Characteristics

• Rare occurrence: Leptomeningeal spread of PNET is a rare phenomenon, accounting for only a small percentage of all PNET cases.
• Aggressive behavior: PNETs with leptomeningeal spread tend to be highly aggressive and have a poor prognosis.
• Symptoms: Patients may present with symptoms such as headaches, seizures, confusion, and weakness or paralysis of the face or limbs.

Diagnostic Challenges

Diagnosing PNET with leptomeningeal spread can be challenging due to its rarity and nonspecific symptoms. A definitive diagnosis often requires a combination of:

• Imaging studies: CT and MRI scans may show diffuse leptomeningeal enhancement, which is indicative of tumor spread.
• Cytological examination: Cerebrospinal fluid (CSF) analysis or leptomeningeal biopsy can reveal the presence of tumor cells.
• Molecular testing: Genetic analysis can confirm the diagnosis and identify specific molecular markers.

References

• [1] Jaffar Kazmi SA, Kershenovich A. Pediatric Primary Diffuse Leptomeningeal Primitive Neuroectodermal Tumor: A Case Report and Literature Review. Pediatr Neurosurg 2017;52:114-21.
• [2] Pathology of the leptomeningeal biopsy was consistent with neuroepithelial neoplasm. Immunohistochemical stains revealed tumor cells strongly positive for synaptophysin and CD56, retained INI-1, but negative for CD99. Cytogenetical analysis revealed absence of EWS translocation and a diagnosis of primary leptomeningeal PNET was established.
• [3] Primitive neuroectodermal tumors (PNETs) are typically present as masses in children and adolescents, but rarely in adults. Diagnoses, management strategies, and prognostication factors are not well established in adult cases of PNETs.

Note: The above information is based on the search results provided within the context.

Common Signs and Symptoms

Primitive neuroectodermal tumors (PNETs) are highly malignant neoplasms that can exhibit leptomeningeal spread, leading to various signs and symptoms. Some common manifestations include:

• Ataxia: A lack of coordination and balance, which may be attributed to direct mass effect and/or raised intracranial pressure [6].
• Cranial nerve palsies: Weakness or paralysis of cranial nerves, which can result in difficulties with swallowing, speaking, or other functions controlled by these nerves.
• Visual problems: Blurred vision, double vision, or loss of vision due to the tumor's impact on the visual pathways [6].
• Headache: A common symptom caused by increased intracranial pressure or direct mass effect from the tumor.
• Seizures: Epileptic seizures can occur as a result of the tumor's presence in the brain.

Additional Symptoms

In addition to these symptoms, PNETs with leptomeningeal spread may also present with:

• Slight bewilderment: A mild confusion or disorientation, which can be an early sign of the tumor's presence [8].
• Slowness in comprehension: Difficulty understanding and processing information due to the tumor's impact on cognitive function.
• Loss of capacity for sustained mental activity: A decline in mental performance and ability to focus over time.

Differential Diagnosis

It is essential to consider primitive neuroectodermal tumors (PNETs) as a possible diagnosis when encountering these symptoms, especially in conjunction with imaging findings such as enhancement of leptomeninges and dura adjacent to the solid tumor [5].

References:

[5] Mechtler LL. Primitive Neuroectodermal Tumor (PNET). In: Osborn AG, Preece SA, editors. Diagnostic Neuroradiology. 3rd ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2019.

[6] Dec 4, 2019 — More specific symptoms, such as ataxia, cranial nerve palsies and visual problems, may be attributable to direct mass effect and/or raised intracranial pressure.

[8] by AG Osborn · 2022 · Cited by 145 — The T2-FLAIR mismatch sign, characterized by T2 homogeneity of the mass with relatively hypointense signal throughout most of the lesion on FLAIR compared with ...

Treatment Options for Obsolete Primitive Neuroectodermal Tumor (PNET) with Leptomeningeal Spread

Primitive neuroectodermal tumors (PNETs) are rare and highly malignant small round cell tumors that can spread to the leptomeninges, a layer of tissue surrounding the brain and spinal cord. The treatment options for PNET with leptomeningeal spread are limited, and the prognosis is generally poor.

Chemotherapy

Chemotherapy remains the mainstay of treatment for PNET with leptomeningeal spread. According to [10], the mainstay of treatment is chemotherapy with cisplatin and etoposide along with other chemotherapeutic agents such as vincristine, doxorubicin, and cyclophosphamide

Based on the search results, it appears that the differential diagnosis for an obsolete primitive neuroectodermal tumor (PNET) with leptomeningeal spread is quite broad. Here are some possible conditions to consider:

• Medulloblastoma: This is a type of brain cancer that can spread to the leptomeninges, and it has been mentioned in several search results as a differential diagnosis for PNET.
• Ewing's sarcoma: This is a rare type of cancer that can affect the bone or soft tissue, and it has similar histological and immunohistochemical characteristics to PNET. It can also spread to the leptomeninges.
• Peripheral primitive neuroectodermal tumors (pPNETs): These are rare, small cell carcinomas that can arise from the primitive nerve cells of the nervous system or outside it. They have been mentioned in several search results as a differential diagnosis for PNET with leptomeningeal spread.
• Meningioma: This is a type of brain tumor that arises from the meninges, and it has been mentioned in one search result as a possible differential diagnosis for PNET with leptomeningeal spread.
• Central nervous system Ewing sarcoma/peripheral primitive neuroectodermal tumor (CNS ES/pPNET): This is a rare type of cancer that can affect the central nervous system, and it has been mentioned in one search result as a possible differential diagnosis for PNET with leptomeningeal spread.

It's worth noting that the World Health Organization (WHO) has revised its classification of central nervous system tumors, and PNET is no longer recognized. Instead, CNS embryonal tumors are classified using specific molecular parameters [10].

In terms of specific characteristics or features that might help differentiate these conditions, it's been mentioned that:

• Leptomeningeal fibrosis can be a feature of primitive neuroectodermal tumor with leptomeningeal spread [9].
• Loss of 17p13.3 is the most frequent abnormality in medulloblastomas and PNETs, accompanied by other genetic abnormalities [12].
• Folate substitution in maternal diet has been claimed to have a protective function against PNET, but this was not confirmed in more recent studies [12].

Overall, it appears that the differential diagnosis for an obsolete primitive neuroectodermal tumor with leptomeningeal spread is complex and requires careful consideration of multiple possible conditions.