Oligodendroglial neoplasms with ganglioglioma-like maturation: a diagnostic pitfall

Abstract

Although oligodendroglial neoplasms are traditionally considered purely glial, increasing evidence suggests that they are capable of neuronal or neurocytic differentiation. Nevertheless, ganglioglioma-like foci (GGLF) have not been previously described. Herein, we report seven examples where the primary differential diagnosis was a ganglioglioma with an oligodendroglial component. These five male and two female patients ranged in age from 29 to 63 (median 44) years at initial presentation and neuroimaging features were those of diffuse gliomas in general. At presentation, the glial component was oligodendroglioma in six and oligoastrocytoma in one; one was low-grade and six were anaplastic. A sharp demarcation from adjacent GGLF was common, although some intermingling was always present. The GGLF included enlarged dysmorphic and occasionally binucleate ganglion cells, Nissl substance, expression of neuronal antigens, GFAP-positive astrocytic elements, and low Ki-67 labeling indices. In contrast to classic ganglioglioma, however, cases lacked eosinophilic granular bodies and CD34-positive tumor cells. Scattered bizarre astrocytes were also common and one case had focal neurocytic differentiation. By FISH analysis, five cases showed 1p/19q codeletion. In the four cases with deletions and ample dysmorphic ganglion cells for analysis, the deletions were found in both components. At last follow-up, two patients suffered recurrences, one developed radiation necrosis mimicking recurrence, and one died of disease 7.5 years after initial surgery. We conclude that GGLF represents yet another form of neuronal differentiation in oligodendroglial neoplasms. Recognition of this pattern will prevent a misdiagnosis of ganglioglioma with its potential for under-treatment.

Diffuse form of dysembryoplastic neuroepithelial tumour: the histological and immunohistochemical features of a distinct entity showing transition to dysembryoplastic neuroepithelial tumour and ganglioglioma

“…Similarly, CD34 immunoreactivity has been published in various low‐grade and also high‐grade gliomas, other than gangliogliomas [18]. Ganglioglioma‐like foci have been observed in oligodendrogliomas, but those tumours, similar to conventional oligodendrogliomas, tend to be negative with CD34 [19].…”

Coexpression of cyclin D1 and alpha-internexin in oligodendroglial tumors

“…Oligodendroglial tumors can be diagnosed by their morphological characteristics, and up to 80 % of oligodendrogliomas and 66 % of anaplastic oligodendrogliomas have concurrent deletion of chromosomal arms 1p and 19q [1,2]. It is now known that parts of oligodendroglial tumors may show neuronal differentiation [1,[3][4][5][6][7]. OPCs a b c d e are the precursor cells of oligodendrocytes and are thought to generate both neurons and oligodendrocytes [9,10].…”

“…Anaplastic oligodendrogliomas show more malignant features, e.g., marked cytological atypia, high mitotic activity, microvascular proliferation, and necrosis [2]. Oligodendroglial tumor cells express glial markers such as S-100 protein and Olig2 [1], and some oligodendroglial tumors may be positive for neuronal markers [1,[3][4][5][6][7][8]. Neuronal features of oligodendroglial tumors are identified by morphological [3,4,6,8] or ultrastructural analyses [5,6].…”

“…Oligodendroglial tumor cells express glial markers such as S-100 protein and Olig2 [1], and some oligodendroglial tumors may be positive for neuronal markers [1,[3][4][5][6][7][8]. Neuronal features of oligodendroglial tumors are identified by morphological [3,4,6,8] or ultrastructural analyses [5,6]. Oligodendrocyte precursor cells (OPCs) are one of the best characterized precursor cell populations in the brain, and to date, several reports indicate that OPCs generate both neurons and oligodendrocytes [9,10].…”

Ewing Sarcoma/Primitive Neuroectodermal Tumor of the Kidney: Two Unusual Presentations of a Rare Tumor

“…This pattern has been considered as an unspecific pattern, but a recent publication described the pattern in oligodendrogliomas, and therefore the pattern seems to indicate neural origin [13]. …”