PMC8769396_01
Preoperative images. (A) The head CT shows marked calcification of the tumor. (B and C) Gadolinium contrast-enhanced T1-weighted images show a homogeneously contrasted tumor in the fourth ventricle. (D) FLAIR image shows mild perifocal edema. (E) Cerebral angiography shows a slight tumor staining from the posterior inferior cerebellar artery (black arrowheads). (F) The abdominal CT shows a contrast-enhancing tumor in the left adrenal gland (white arrowheads). CT: computed tomography, FLAIR: fluid-attenuated inversion recovery.
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F1
Head computed tomography (CT) showed enlargement of the ventricles and a tumor-like lesion, 3.5-cm in diameter with marked calcification in the fourth ventricle (Fig. 1A). In addition, an abdominal CT scan taken for systemic search to rule out the possibility of metastatic tumor indicated a left adrenal tumor (Fig. 1F). On head magnetic resonance (MR) images, the tumor-like lesion was homogeneously enhanced with well-defined borders and mild perifocal edema (Fig. 1B-1D). Cerebral angiography showed only slight tumor staining from the left posterior inferior cerebellar artery (Fig. 1E).
Postoperative images. (A-C) The tumor has been removed except for a calcified, residual tumor on the cerebellar side.
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F2
Postoperative images showed minimal, calcified residual tumor on the cerebellar side (Fig. 2A-2C), and ventricle size was normalized.
Pathological images of the CPP (A-G). (A) H&E staining shows cuboidal to cylindrical epithelium proliferating in a papillary structure with an axis of vascular connective tissue. Immunostaining showed (B) S-100 positive, (C) vimentin positive, (D) prealbmin positive, (E) AE1/AE2 positive, and (F) p53 negative staining. (G) Ki-67 labeling index was 1.4%. (H) Pathological image of the pheochromocytoma shows large multilineage cells proliferate in a spore-like arrangement. H&E: hematoxylin and eosin.
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F3
Histopathological analysis showed that the tumor in the fourth ventricle consisted of cylindrical or cuboidal tumor cells arranged in a papillary fashion with vascular connective tissue as the stroma (Fig. 3A). The tumor stained positive for S-100 protein, vimentin, prealbumin, and AE1/AE3, and negative for p53 (Fig. 3B-3E and 3G). The Ki-67 labeling index was 1.4% (Fig. 3F). On the other hand, the adrenal tumor was diagnosed as pheochromocytoma (Fig. 3H).