case_images: PMC6393824_01
case_images: Sagittal T2-weighted (T2W) MRI of the head and cervical area illustrating a large mass with extensive nasal invasion, destruction of the cribriform plate and intracranial expansion in a cat. The mass was predominantly hypointense with some hyperintense areas on T2W images compared with the grey matter. Note a linear T2W hyperintense lesion throughout the mid-cervical spinal cord, consistent with syringomyelia, which continued caudally to the thoracic spinal cord segments
case_images: 10.1177_2055116919833732-fig1.jpg
case_images: PMC6393824_01_10.1177_2055116919833732-fig1.jpg
case_images: fig1-2055116919833732
case_images: MRI revealed a single large (4.8 cm x 1.7 cm x 2.7 cm) space-occupying mass of extra-axial origin, centred slightly left of midline over an obliterated cribriform plate (Figures 1 and 2). T2W hyperintense lesion throughout the mid-cervical and thoracic spinal cord, consistent with syringomyelia, was observed (Figure 1). Mitotic figures were uncommon (<1 mitosis per 10 high-power fields) and occasional apoptotic cells were visible.
case_images: Brain MRI T1-weighted post-contrast sequences. (a) Dorsal view. The mass was centred slightly left of midline over an obliterated cribriform plate. The intracranial portion of the mass filled the rostral cranial fossa, and extended into the middle cranial fossa. A dural tail bordering the intracranial portion of the mass at its rostral aspect on the left was visible (arrowhead). (b) Midline sagittal view. The mass displayed extensive nasal, frontal sinus and intracranial invasion, cribriform plate destruction, hydrocephalus and transtentorial and cerebellar herniation. (c) Transverse view. Note the severe displacement of the frontal lobes by the mass, centred left of midline
case_images: 10.1177_2055116919833732-fig2.jpg
case_images: PMC6393824_01_10.1177_2055116919833732-fig2.jpg
case_images: fig2-2055116919833732
case_images: MRI revealed a single large (4.8 cm x 1.7 cm x 2.7 cm) space-occupying mass of extra-axial origin, centred slightly left of midline over an obliterated cribriform plate (Figures 1 and 2). The mass had a lobular appearance (Figure 2). A dural tail bordering the intracranial portion of the mass at its rostral aspect on the left was visible on T1W post-contrast sequences (Figure 2a). There were moderate perilesional oedema and marked caudal displacement of the brain with midline shift towards the right, resulting in transtentorial and cerebellar herniation (Figure 2b).
case_images: Histopathology image illustrating microscopic characteristics of the mass. The nasal mucosa was replaced by a population of spindle-shaped-to-occasionally polygonal cells. Foci of mineralisation were present within them. The infiltrating cells had large, ovoid nuclei, reticulate-to-clumped chromatin, prominent eosinophilic nucleoli and hyaline, and granular or vacuolated eosinophilic cytoplasm with indistinct borders. This was consistent with a transitional (mixed) meningioma. Haematoxylin and eosin stain, x 40 objective
case_images: 10.1177_2055116919833732-fig3.jpg
case_images: PMC6393824_01_10.1177_2055116919833732-fig3.jpg
case_images: fig3-2055116919833732
case_images: There were small numbers of neutrophils in some areas (Figure 3).