case_images: PMC7472124_01
case_images: CT and MR images of the cranium and brain at diagnosis. Dorsal (A) and parasagittal (B) CT images showed the defect of the left cribriform plate (red arrow). On dorsal (C) and parasagittal (D) T2-weighted MR images, the left olfactory bulb protruded into the nasal cavity through the defect (red arrowheads).
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case_images: PMC7472124_01_fvets-07-00532-g0001.jpg
case_images: F1
case_images: Toshiba, Tochigi, Japan), a defect of the left cribriform plate and rightward deviation of the nasal septum were observed, and an iso-dense mass lesion with cerebral parenchyma occupied the nasal cavity. This mass lesion was continuous with the cerebral parenchyma (Figures 1A,B). Tokyo, Japan), a lesion continuous with the cerebral parenchyma occupying the nasal cavity exhibiting iso-high intensity on T2-weighted imaging (TE: 100 ms, TR: 4,500 ms), iso-high intensity on FLAIR (TE: 100 ms, TR: 9,000 ms), and iso-intensity on T1-weighted imaging (TE: 13 ms, TR: 350 ms) was noted (Figures 1C,D). This region was mildly enhanced with gadolinium (OMNISCAN
case_images: Intraoperative photographs of the intranasal meningoencephalocele. After approaching the lesion by transfrontal craniotomy, a discolored mass connected to the brain was easily identified (A). After resecting the mass the defect was covered with the sections of the tunica vaginalis which were further covered by fibrin glue (B).
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case_images: PMC7472124_01_fvets-07-00532-g0002.jpg
case_images: F2
case_images: Tokyo, Japan), and the lesion was approached. The right cribriform plate was confirmed, but the left cribriform plate was absent and a mass considered to be the cerebral parenchyma prolapsed from this region. The prolapsed mass was entirely yellow in color compared with normal brain tissue (Figure 2A). Tissue adhesion, CSL Behring K.K., Tokyo, Japan), were used. The tunica vaginalis excised before brain surgery was arranged to cover the defective region of the cribriform plate over the stump of the mass, and the liquid tissue adhesive was applied to the surrounding tissue (Figure 2B).
case_images: The resected specimen contained nerve tissues, leading to a diagnosis of meningoencephalocele. An increase in astrocytes and infiltration of inflammatory cells which consisted of many lymphocytes, plasmacytes, macrophages and a few neutrophils were recognized in the specimen (H&E stain, bar = 200 mum).
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case_images: PMC7472124_01_fvets-07-00532-g0003.jpg
case_images: F3
case_images: The excised specimen was immediately fixed with formalin and histopathologically examined (Figure 3).
case_images: Postoperatve CT and MR images of the cranium and brain 7 months after surgery. Parasagittal CT images (A) showed slightly superabsorbent structures separate cranial cavity and nasal cavity (red arrow). On parasagittal T2-weighted MR images (B), there is no apparent departure of the brain into the nasal cavity.
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case_images: PMC7472124_01_fvets-07-00532-g0004.jpg
case_images: F4
case_images: Seven months after surgery, the formation of the septum dividing the nasal cavity and brain were confirmed on MRI and CT (Figure 4).