Pineal region ganglioglioma: A neoplasm with a bimodal age distribution

Abstract

Background: Gangliogliomas arise very rarely in the pineal region, where their natural histories and pathologic features are poorly understood.

Case description: In this report, we describe a 36-year-old woman who presented with a seizure followed by worsening headache, dizziness, confusion, and intermittent left facial numbness over the next few weeks. A head CT scan showed a partially calcified pineal region mass with hydrocephalus. After an endoscopic third ventriculostomy, the patient underwent a resection of the tumor that contained dysplastic ganglion cells and piloid glial cells. Molecular profiling of this CNS WHO Grade 1 ganglioglioma revealed polysomies of chromosomes 7 and 9, and a BUB1 variant of uncertain significance, without known MAP kinase pathway alterations. From a review of the literature, we found two distinct age distributions for pineal ganglioglioma, with modes at 1 and 36 years of age.

Conclusion: Although very rare, this tumor should be considered in the differential diagnosis of pineal region tumors in children and young adults.

Keywords: Chromosome 7 polysomy; Epiphysis; Glioneuronal; Targeted next-generation sequencing; Tumor.

Figure 1:

Preoperative and postoperative imaging of the pineal region neoplasm. (a) Axial T1-weighted MRI shows a mass, measuring 3.0 × 2.1 cm, at the level of the pineal gland with heterogeneous, mostly solid enhancement. (b) Axial T1-weighted MRI after resection reveals minimal linear enhancement along the margin of the surgical cavity.

Figure 2:

Histologic features of the pineal region neoplasm. (a) Hematoxylin and eosin-stained sections of the resection specimen show a pleomorphic neoplasm with thick, fibrillary, cytoplasmic processes. Some cells have ovoid nuclei, and some have spindle-shaped nuclei. (b) Eosinophilic granular bodies and Rosenthal fibers are noted on a frozen section. Low magnification (c) and high magnification (d) photomicrographs reveal many ganglioid cells with prominent nucleoli. (e) Collections of mixed chronic inflammatory cells can be seen around some blood vessels. (f) Tumor cells are present adjacent to hyalinized blood vessels and corpora arenacea.

Figure 3:

Immunophenotype and EGFR gene copy number of the pineal region neoplasm. (a) GFAP immunoreactivity is diffusely positive in the glial component. (b) Olig2 is expressed in the majority of cells. (c) A phosphorylated neurofilament immunostain highlights many tumor cell axons. (d) Granular synaptophysin immunoreactivity, including in the soma and axons of a gangliocytic tumor cell (arrow). (e) CD34 is positive in a subset of tumor cells with highly branched morphology and in blood vessels. (f) Evaluation of EGFR (black) and chromosome 7 (CEP7 probe, red) through silver in situ hybridization shows chromosome 7 polysomy without selective EGFR amplification.