Magnetic resonance imaging of a giant frontal hemorrhagic mucocele with intracranial extension in a cat

Abstract

A 6-year-old domestic short-haired cat was presented with an acute onset of right cortical encephalopathy. Magnetic resonance imaging (MRI) performed 4 days after the onset of clinical signs revealed a lesion originating from the right frontal sinus with intracranial extension and compression of the right frontal lobe. The lesion was T1-weighted hypointense and T2-weighted and fluid-attenuated inversion recovery hyperintense. Signal voids within the lesion were observed on T2* images, consistent with hemorrhage. Peripheral ring enhancement was visible on postcontrast sequences. These features were consistent with a giant hemorrhagic mucocele. To the authors' knowledge, this is the first report of MRI characteristics of this lesion in a cat.

Imaging diagnosis of paranasal sinus mucocele in a Yorkshire Terrier dog

“…In veterinary medicine, there have been few reports of diagnostic imaging findings of a paranasal sinus mucocele, as these are mainly about the frontal mucocele with an intracranial extension or traumainduced (Adamo 2005;Sessums and Lane 2008;Raul et al 2018;Vandenberghe et al 2020). On the CT, the paranasal mucocele is shown as a homogenous, hypoattenuating area with a ring enhancement (Raul et al 2018) like that in our case also.…”

“…On the CT, the paranasal mucocele is shown as a homogenous, hypoattenuating area with a ring enhancement (Raul et al 2018) like that in our case also. On the MRI, a paranasal sinus mucocele is shown as heterogeneously hypointense on the T1-weighted and hyperintense on the T2-weighted images, but this can vary depending on the component of the mucocele (Sessums and Lane 2008;Vandenberghe et al 2020). In addition to the above imaging findings, in the case of an intracranial extension, a well-demarcated heterogeneous lesion involving all frontal sinuses extends into the intracranial space via the focally-thinned frontal bone (Adamo 2005;Sessums and Lane 2008;Vandenberghe et al 2020).…”

“…On the MRI, a paranasal sinus mucocele is shown as heterogeneously hypointense on the T1-weighted and hyperintense on the T2-weighted images, but this can vary depending on the component of the mucocele (Sessums and Lane 2008;Vandenberghe et al 2020). In addition to the above imaging findings, in the case of an intracranial extension, a well-demarcated heterogeneous lesion involving all frontal sinuses extends into the intracranial space via the focally-thinned frontal bone (Adamo 2005;Sessums and Lane 2008;Vandenberghe et al 2020). In a trauma-induced paranasal sinus mucocele, destruction of the cranium with multiple irregular osteolysis may be found (Raul et al 2018).…”

“…A paranasal sinus mucocele is thought to result from occlusion of the sinus ostium by inflammation, fibrosis, trauma, abnormal conformation, or a mass; however, the definitive cause remains undetermined (Kawaguchi et al 2002;Eggesbo 2006). Despite its benign histological nature, it erodes adjacent bony walls and/or expands intracranially (Adamo 2005;Capra et al 2012;Vandenberghe et al 2020). Few reports about mucoceles located in paranasal sinuses in dogs and cats have been documented in literature.…”

Computed tomographic imaging of a maxillary sinus mucocele in an 8‐year‐old French Bulldog

“…6 Recent veterinary publications have added to our knowledge of this condition in small animals; however, to date, only eight cases have been reported in dogs and two cases in E76 cats. [7][8][9][10][11][12][13][14][15][16] Nearly all of these mucoceles have arisen from the frontal sinus cavity, some extending into the cranial cavity and orbit (referred to as giant mucoceles). [14][15] One recently published case is thought to have arisen from the ethmoid sinus of a Yorkshire Terrier dog, creating a lesion almost entirely peripheral to the nasal cavity and centered in the lacrimal fossa.…”