case_images: PMC11763826_01
case_images: The sagittal T2 MRI head showed a pineal region mass with a hyperintense anterior cystic component.
case_images: cureus-0017-00000077989-i01.jpg
case_images: PMC11763826_01_cureus-0017-00000077989-i01.jpg
case_images: FIG1
case_images: A 9 mm anterior cystic component was hypointense on T1 and strongly hyperintense on T2 with post-gadolinium enhancement (Figure 1).
case_images: Axial CT head with hydrocephalus / third ventricle dilatation secondary to the aqueduct of Sylvius obstruction by the pineal region mass.
case_images: cureus-0017-00000077989-i02.jpg
case_images: PMC11763826_01_cureus-0017-00000077989-i02.jpg
case_images: FIG2
case_images: FLAIR signal. The third ventricle measured 4.9 x 1.8 cm (Figure 2). Foci of diffusion restriction were present, but the diffusion and SWAN studies were otherwise non-contributory.
case_images: PMC11763826_02
case_images: Biopsy of the pineal region mass showing cellular proliferation with epithelial appearance, forming papillae lined by tall cylindrical cells with clear eosinophilic fibrillar cytoplasm and hyperchromatic oval nuclei.
case_images: cureus-0017-00000077989-i03.jpg
case_images: PMC11763826_02_cureus-0017-00000077989-i03.jpg
case_images: FIG3
case_images: Biopsy of the pineal region mass showed cellular proliferation with epithelial appearance, forming papillae lined by tall cylindrical cells with clear eosinophilic fibrillar cytoplasm and hyperchromatic oval nuclei (Figure 3).
case_images: Hematoxylin and eosin staining showed the tumor's papillary structure. CD56/NCAM was strongly expressed. CK 18/8 and GFAP were focally expressed. Ki-67 was low on the initial biopsy, showing a proliferation index between 1% and 2%. This tumor was negative for NF, epithelial membrane antigen (EMA), synaptophysin, chromogranin, and E-CAD, among others.
case_images: cureus-0017-00000077989-i04.jpg
case_images: PMC11763826_02_cureus-0017-00000077989-i04.jpg
case_images: FIG4
case_images: Ki-67 was 1-2% (Figure 4).
case_images: PMC11763826_03
case_images: A sagittal view of the planning CT scan shows the 50 Gy isodose line (green) covering the PTV (red). The 54 Gy isodose line (yellow) curves superiorly to respect the brainstem (blue) and optic chiasm (magenta) radiation dose constraints.. PTV, planning target volume
case_images: cureus-0017-00000077989-i05.jpg
case_images: PMC11763826_03_cureus-0017-00000077989-i05.jpg
case_images: FIG5
case_images: PMC11763826_04