case_images: PMC6763664_01
case_images: Axial T1 (a) and T2 gradient echo (b); coronal T2WI (c) and sagittal post-Gadolinium T1W1 (d). Heterogeneous solid- cystic mass obstructing the third ventricle, located at the foramen of Monro (blue arrow), at the anterosuperior aspect of the third ventricle, causing a deviation of the midline (white arrow) and obstructive hydrocephalus. The anterior portion of the lesion is predominantly cystic with a moderate hyperintense signal (yellow arrows). The posterior portion is predominantly solid (red arrow), has hypointense areas suggestive of either calcifications or a hemorrhagic component (green arrow), and shows heterogeneous enhancement (pink arrow).
case_images: SNI-10-169-g001.jpg
case_images: PMC6763664_01_SNI-10-169-g001.jpg
case_images: F1
case_images: T2WI and on gradient echo (GRE) T2WI, and the anterior portion was predominantly cystic with both hyper- and hypointense areas on T1WI and T2WI, with no suppression on fluid- attenuated inversion recovery (FLAIR) and no restriction to diffusion. The solid portion was hypointense on T1WI and demonstrated heterogeneous areas of enhancement after gadolinium contrast agent administration; there were also some peripheral sparse areas of enhancement in the cystic portion of the lesion. These heterogeneous peripheral enhancements and hypointensity on GRE TW2I are consistent with either hemosiderin or calcifications, raising concern for an atypical colloid cyst or a cystic craniopharyngioma [Figure 1].
case_images: Intraoperative images (a and b) microsurgical removal of the colloid cyst's capsule (blue arrow) using endoscopic visualization and resection of the colloid cyst (b). Gross specimen (c) displaying nodular appearance surrounded by a delicate irregular membrane, with a yellowish color (yellow arrows) and friable areas (inside white ellipses), size: 2.5 cmx2.0x2.0cm and weigh: 7.0 g.
case_images: SNI-10-169-g002.jpg
case_images: PMC6763664_01_SNI-10-169-g002.jpg
case_images: F2
case_images: The solid part was firm, grayish-black in color, and avascular [Figure 2].
case_images: Photomicrograph (hematoxylin-eosin stain, magnification x4.0 [a] and x20.0 [b and c]) images of the specimen: colloid cyst lined by a single layer of cuboidal, partially flattened non- ciliated and ciliated epithelial cells. There was a high prevalence of macrophages and epithelioid cells (inside black ellipse), many of which included refractile material and hemosiderin (blue arrows); polymorphonuclear leukocytes were diffusely spread out throughout the granuloma. In addition, cholesterol clefts (green arrows) and lymphocytes were seen in focal sets.
case_images: SNI-10-169-g003.jpg
case_images: PMC6763664_01_SNI-10-169-g003.jpg
case_images: F3
case_images: Polymorphonuclear leukocytes were diffusely spread out throughout the granuloma [Figure 3].
case_images: The immediate post-operative axial T1WI (a) demonstrated an almost complete reduction of the lesion, with some sparse areas of contrast agent enhancement (yellow arrows). There is normalization in the lateral ventricle size. Coronal T2WI (b) shows post-surgical changes in the left frontal region (inside the yellow circle). There is hypointense material inside the ventricular system consistent with the degradation of hemoglobin (red arrows).
case_images: SNI-10-169-g004.jpg
case_images: PMC6763664_01_SNI-10-169-g004.jpg
case_images: F4
case_images: The immediate post-operative MRI demonstrated an almost complete reduction of the cystic lesion, with some sparse areas of contrast agent enhancement, and normalization in the lateral ventricle size [Figure 4].