Massively calcified low-grade glioma - a rare and distinctive entity

A "polymorphous low-grade neuroepithelial tumor of the young (PLNTY)" diagnosed in an adult. Report of a case and review of the literature

Background:

Polymorphous low-grade neuroepithelial tumor of the young (PLNTY) is a rare neuropathological entity, recently introduced in neuro-oncology. These tumors, histologically similar to oligodendrogliomas, cause epilepsy, occurring in children and young adults. Only few cases of PLNTY have been described in literature and all reported cases invariably focused on the onset of these tumors in children and young adults.

Case Description:

We report the case of a 50-year-old woman suffering from epilepsy since the 1^st year of her life. Computed tomography scan and magnetic resonance imaging of the brain documented the presence of a calcified mass involving left temporal lobe. The tumor was surgically excised and the histological examination showed a hypocellular and massively calcified neoplasm with morphological and immunohistochemical features consistent with the diagnosis of “PLNTY.”

Conclusion:

A review of the literature revealed that there are 31 cases of PLNTY reported in literature, most of which are children or young adults. The present case represents the second PLNTY diagnosed in a middle-aged adult to the best of our knowledge, suggesting that PLNTY should always be included in the differential diagnosis of low-grade brain tumors, also in adult patients.

BRAF Alteration in Central and Peripheral Nervous System Tumors

BRAF (alternately referred to as v-raf murine sarcoma viral oncogene homolog B1) is a proto-oncogene involved in the mitogen-activated protein kinase (MAPK) pathway. BRAF alterations are most commonly missense mutations or aberrant fusions. These mutations are observed in numerous primary central nervous system tumors as well as metastases. This review discusses the prevalence of BRAF alteration within select notable CNS tumors, and their prognostic associations. Included are some novel entities such as diffuse leptomeningeal glioneuronal tumor (DLGNT), polymorphous low grade neuroepithelial tumor of the young (PLNTY), and multinodular and vacuolating neuronal tumor (MVNT). Knowledge of this gene’s integrity in CNS and PNS tumors can have profound diagnostic and therapeutic implications. Also reviewed are the current state of targeted therapy against aberrant BRAF as it pertains mostly to the CNS and to a lesser extent in PNS, and certain diagnostic aspects.