Multinodular and vacuolating neuronal tumor of the cerebrum is a clonal neoplasm defined by genetic alterations that activate the MAP kinase signaling pathway

Excerpt

Initially described in 2013, multinodular and vacuolating neuronal tumor of the cerebrum (MVNT) is a low-grade neuronal neoplasm of the cerebral hemispheres composed of small to medium sized neuronal cells arranged in nodules involving the deep cortex and subcortical white matter, showing prominent intracytoplasmic and stromal vacuolation [8]. The tumor cells are typically immunopositive with some glial and neuronal markers (OLIG2 and synaptophysin), but negative for others (GFAP and NeuN), and are associated with ramified CD34-positive processes in adjacent parenchyma. The radiologic features of MVNT are distinct and include predominantly solid, T2-hyperintense lesions in the deep cortical ribbon and superficial white matter with variable internal nodularity and typically absent contrast enhancement [1, 8, 11]. Patients may be asymptomatic or can present with seizures or headaches, and all pathologically proven cases have reportedly followed a benign clinical course to date [1, 8, 11]. The molecular basis of MVNT is unknown, and some authors have suggested that MVNT is a malformative lesion rather than a true clonal neoplasm [4, 13]. …