Intraventricular pituicytoma: illustrative case

Abstract

Background: Pituicytoma is a rare glial neoplasm from pituicytes of the neurohypophysis or infundibulum. It occurs in the sella and suprasellar area, and it is extremely uncommon to observe intraventricular pituicytoma without affecting the infundibulum or infundibular recess.

Observations: A 69-year-old man had suffered progressive dementia for 6 months. Magnetic resonance imaging revealed a solid, homogeneously enhancing mass with flow voids within the anterior third ventricle. The sella, suprasellar area, infundibulum, and infundibular recess were unaffected. The patient underwent a transcallosal transchoroidal approach, which ended in partial removal of the tumor due to significant tumoral bleeding. A second surgery resulted in its subtotal removal. The tumor had bipolar cells, and their nuclei were immunoreactive for thyroid transcription factor-1. A DNA methylation analysis corresponded to the methylation class of pituicytoma, granular cell tumor, and spindle cell oncocytoma. Pituicytoma was the diagnosis based on these results. A systematic review identified 5 intraventricular pituicytoma cases.

Lessons: Intraventricular pituicytoma can grow without involvement of the infundibulum or infundibular recess. The current case suggests that pituicytes of the hypothalamic tuber cinereum can also give rise to pituicytoma. Because of the hypervascular nature of intraventricular pituicytomas, it is imperative to control intraoperative bleeding with attention to the adjacent hypothalamus. https://thejns.org/doi/10.3171/CASE24247.

Keywords: case report; intraventricular; pituicytoma; third ventricle.

FIG. 1.

Preoperative images of the tumor in the third ventricle. Head CT images show an isodense (arrow, A) and enhanced mass (arrow, B) with its feeding arteries (double-headed arrow). Axial T1-weighted MR images show an isointense solid mass (arrow, C) with bright contrast enhancement by gadolinium injection (arrow, D). A T2-weighted hyperintense mass in the third ventricle associated with edema (arrowheads, E) and multiple flow void signals of the feeding arteries and intratumoral vessels (double-headed arrows). Angiography shows the feeding arteries (arrowheads, F) from the anterior communicating artery, anterior choroidal artery, and anterior perforating arteries from the proximal anterior cerebral artery (double-headed arrow). The mass occupied the anterior part of the third ventricle, and the infundibulum (arrow, G) is intact. The mass occludes the bilateral foramen of Monro (arrows, H), and the bilateral lateral ventricles are enlarged (arrowheads). The posterior perforating arteries (double-headed arrows, I and J) from the proximal posterior cerebral artery send tortuous tumor vessels (arrowheads, J).

FIG. 2.

Operative views via the transcallosal transchoroidal approach. The view at the first surgery shows a firm and reddish mass (arrow,A) through the right foramen of Monro behind the fornix (arrowheads) and choroidal fissure (double-headed arrow). Bleeding from the tumor was difficult to control (B). The first surgery was finished in a partial removal after confirmation of the cerebral aqueduct (arrowhead,C). Postoperative gadolinium-enhanced MR image shows a residual mass (arrow,D). An axial T2-weighted MR image shows exaggerated edema in the bilateral hypothalamus (arrowheads,E). The operative view at the second surgery shows the residual tumor (arrow,F) through the right foramen of Monro behind the fornix (arrowheads) and choroidal fissure (double-headed arrow). The thalamostriate vein (TSV) and its transition to the internal cerebral vein (ICV) are exposed. The view from the left lateral ventricle via the transseptal approach shows the left choroidal plexus (double-headed arrow, G) and a firm tumor (arrow) behind the left fornix (arrowheads). The mass was removed via the right transforaminal approach by coagulating the feeding arteries (black arrowhead, H), and the left third ventricular wall was intact (white arrowhead). The mass (arrow, I) was detached from the intact third ventricular floor (arrowheads). The mass (arrows, J) was removed from the forceps (F) by disconnecting it from the right lateral wall of the third ventricle (K). The final view confirms the cerebral aqueduct (black arrowhead, L) and the third ventricular floor (white arrowheads). Postoperative sagittal (M) and axial (N) gadolinium-enhanced MR images show subtotal removal. A T2-weighted MR image (O) shows a postoperative hyperintense change in the right hypothalamus (white arrowhead).

FIG. 3.

Photomicrographs of tumor sections. A cellular neoplasm composed of spindle cells (hematoxylin and eosin, A) positive for TTF-1 (B). Bars = 100 µm. DNA methylation-based t-SNE analysis (C)indicates that the present specimen belongs to the sella group (dotted circle).

FIG. 4.

Flow diagram of studies for the systematic review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 statement.