Anaplastic changes of diffuse leptomeningeal glioneuronal tumor with polar spongioblastoma pattern

Abstract

Diffuse leptomeningeal glioneuronal tumor (DLGNT) is a rare glioneuronal neoplasm with oligodendroglioma-like cells confined in the subarachnoid spaces. A great majority of DLGNT are histologically low grade. However, some tumors show features of anaplasia with increased mitotic and proliferative activity. Due to the limited number of patients and inadequate clinical follow-up reported to date, the WHO classification does not yet assign a distinct WHO grade to this entity. Polar spongioblastoma pattern, in which bipolar cells are arranged in parallel with palisading nuclei, remains poorly understood about the pathological process of forming this pattern. We experienced a case of 22-year-old man developing DLGNT with extensively distributed anaplastic changes involving polar spongioblastoma pattern and the secondary tumor invasion to brain parenchyma in 4½ years before the autopsy. Clinical and pathological courses of the patient are presented with radiological, histopathological, and genetic examinations. This is the first report demonstrating the immunohistological and genetic evaluation of a DLGNT with polar spongioblastoma pattern.

Diffuse Leptomeningeal Glioneuronal Tumor in a 4.5-year-old Girl: A Case Report and Review of the Literature

“…2,5,11,14 In some cases, the tumor formed intraparenchymal lesions, mostly located in the spinal cord. 1,9,14 In the current case, MRI showed multiple intramedullary lesions. Typically, these lesions are considered progressive, 2,5,14 as they were in our patient.…”

“…11 Cases with atypical findings have been also reported. 7,9 In our patient, the tumor consisted of neurocyte-like and glial-like cells, with areas containing oligodendroglioma-like cells. Presented histological findings are not specific and can differ between patients, which makes the additional molecular analysis necessary.…”

“…[5][6][7][8][9][10][11][12][13] Several cases in adults have been reported. 3,8,12 Most common symptoms include nausea and vomiting, 2-4,12-14 headache, [2][3][4][5][6][7]9,11,12,14 seizures, 11,12,15 limbs weakness, 2,4,7,9,11 loss of vision, 9,11 and altered mental state (confusion). 2,8,9 Our patient presented with headache, vomiting, and right eye convergent strabismus.…”

“…DLGNTs are typically positive for S100, Olig2, GFAP, and synaptophysin expression, 3,4,6,7,9 but immunoreactivity can differ between cases. The tumor is becoming increasingly recognized as having BRAF and KIAA1549 genes fusions, 1p deletions 2,6,9,13 and rarely 1p/19q codeletion 7,11 but a significant part of DLGNTs are negative for these markers. 2,3,6,8,10,12,14,16 In the reported case, the tumor showed BRAF and KIAA1549 fusion but without the most common BRAF gene mutations.…”

“…3,8,12 Most common symptoms include nausea and vomiting, 2-4,12-14 headache, 2-7,9,11,12,14 seizures, 11,12,15 limbs weakness, 2,4,7,9,11 loss of vision, 9,11 and altered mental state (confusion). 2,8,9 Our patient presented with headache, vomiting, and right eye convergent strabismus. Typical features DLGNT features from all the reported cases are summarized in ►Table 1.…”