case_images: PMC9610524_01
case_images: Fetal magnetic resonance imaging coronal 1 image showing large fluid signal intensity structure occupying much of the right side of posterior fossa with the displacement of the right cerebellum.
case_images: SNI-13-449-g001.jpg
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case_images: F1
case_images: There was no evidence of acute or old hemorrhage [Figure 1].
case_images: Cranial ultrasound image with fluid echogenicity structure occupying most of the right side of posterior fossa with a compressed right cerebellum.
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case_images: F2
case_images: Figure 2 shows cranial ultrasound scan on day 4 of life.
case_images: Computed tomography brain coronal image showing dilated lateral and third ventricles and hydrocephalus.
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case_images: F3
case_images: Figures 3 and 4 show computed tomography brain appearances which were suggestive of congenital posterior fossa arachnoid cyst causing compression of adjacent structures with extensive internal hydrocephalus.
case_images: Computed tomography brain sagittal showing that the posterior fossa fluid density structure has enlarged and fourth ventricle is now compressed. Findings consistent with new obstructive noncommunicating hydrocephalus secondary to an enlarging cystic lesion.
case_images: SNI-13-449-g004.jpg
case_images: PMC9610524_01_SNI-13-449-g004.jpg
case_images: F4
case_images: Figures 3 and 4 show computed tomography brain appearances which were suggestive of congenital posterior fossa arachnoid cyst causing compression of adjacent structures with extensive internal hydrocephalus.
case_images: Magnetic resonance imaging brain and cervical cord scan coronal showing dilated lateral and third ventricles, but these have reduced in size following shunt (in the right lateral ventricle). Sulci are now evident as a sign of response to hydrocephalus intervention.
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case_images: F5
case_images: Follow-up MRI brain and cervical cord scan 4 weeks later noted only mild decompression of the supratentorial ventricular system with VP shunt in place [Figures 5 and 6].
case_images: Magnetic resonance imaging brain sagittal view with large cyst over the right cerebellum and extending toward posterior aspect of third ventricle and effacing septum pellucidum.
case_images: SNI-13-449-g006.jpg
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case_images: F6
case_images: Follow-up MRI brain and cervical cord scan 4 weeks later noted only mild decompression of the supratentorial ventricular system with VP shunt in place [Figures 5 and 6].
case_images: Magnetic resonance imaging brain scan sagittal with persistent large cyst and associated mass effect within the posterior fossa, effacement of the cerebrospinal fluid spaces at the level of the foramen magnum, and descent of cerebellar tonsils to the level of C2
case_images: SNI-13-449-g007.jpg
case_images: PMC9610524_01_SNI-13-449-g007.jpg
case_images: F7
case_images: This might relate to over shunting of cerebrospinal fluid (CSF) [Figure 7].