Polymorphous low-grade neuroepithelial tumor of the young: Rare tumor and review of the literature

Abstract

Polymorphous low-grade neuroepithelial tumor of the young (PLNTY) is a recently described low-grade neuroepithelial tumor with an infiltrative growth pattern and oligodendrocyte-like cells that are CD34 immunopositive. Correlating histology and results from molecular testing is critical to correctly diagnosing PLNTY, as its histologic appearance is similar to oligodendrogliomas and shares genetic abnormalities common to other low-grade epilepsy associated tumors (LEATs). In this case report, we describe a 31-year-old female with intractable epilepsy found to have a temporal mass and diagnosed with PLNTY after histopathologic and molecular testing. We describe the radiographic, histologic, and genetic features in relation to the epileptic and oncologic outcomes for this patient. Then, we compare these features and outcomes to other cases of PLNTY described in the literature.

Polymorphous Low-Grade Neuroepithelial Tumor of the Young (PLNTY): Scoping Review of Case Reports and Case Series

“…After removing duplicates, 27 articles were found to be eligible for inclusion in the review. 1 2 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 One article was excluded as there was a publication available in English by the same authors with similar reported findings. 31 The details of the study selection process in the form of a flowchart are shown in Fig.…”

“…11 33 Though the age predilection for PLNTYs has been reported to be 2 to 57 years, most cases are under 30 years of age. 1 2 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 It has an equal sex preponderance. Among the 49 cases accounted for in Table 1 , only five cases (including the index case) had nonepileptic clinical presentations, such as headache, imbalance, and behavioral abnormalities.…”

“…1 Ki-67 labelling index is typically less than 5%. 23 PLNTYs are known to harbor MAPK pathway alterations in the form of demonstrable BRAF or FGFR2/FGFR3 mutations. 17 On the contrary, their typical mimic, oligodendrogliomas, have IDH mutations and 1p/ 19q co-deletions.…”

Adult-type and Pediatric-type Diffuse Gliomas

“…Polymorphous low-grade neuroepithelial tumor of the young (PLNTY) is also a WHO grade 1 tumor associated with seizures [49,50]. The PLNTY is characterized by alterations of the mitogen-activated protein kinase-pathway (MAPK pathway) such as a mutation of the gene for the rapid accelerated fibrosarcoma oncogene type B at position 600 (BRAF V600E) or even a gene fusion involving the gene for the fibroblast growth factor receptor 2 or 3 (FGFR2 or FGFR3) in combination with typical histological features, such as oligodendroglioma-like areas, a diffuse growth pattern, as well as the expression of cluster of differentiation 34 (CD34) and oligodendrocyte transcription factor 2 (OLIG2) [50][51][52][53]. Despite the median age of 15.5 years [49], several patients with PLNTY up to the 6th decade of life have been reported [49,54,55].…”

Radiological and surgical aspects of polymorphous low-grade neuroepithelial tumor of the young (PLNTY)

“…PLNTY is a typical low-grade epilepsy-associated tumor recently described and introduced in Central Nervous Tumor-World Health Organization (CNS-WHO) 2021 classification [ 2 , 3 ]. Before the last updated classification, PLNTY it was considered to take part of a group known as low-grade epilepsy-associated tumors (LEATs), an umbrella of developmental tumors, with favorable clinical outcomes, with varying histologic appearances, associated with early-onset seizures, since other glial tumors, such as pilocytic astrocytomas or oligodendrogliomas, usually had distinct diagnostic criterion that assists in further clinical management [ 1 , 4 ]. Several distinguishing factors of PLNTY may be implicated in its pathogenesis and clinical manifestation, the most suspicious of which are BRAF V600E gene mutant, increased CD34 expression, and FGFR gene fusion products [ 5 ].…”