Spheric mass beneath the alar base: MR images of nasolabial cyst and schwannoma

Abstract

We report 2 cases of nasolabial cyst and a case of schwannoma beneath the alar base that required a differential diagnosis because of clinical features and MR images that resembled the nasolabial cyst. The morphologic analysis on MR images revealed the characteristic appearance of the nasolabial cyst, and the sagittal MR image may be most helpful for diagnosing this rare disease.

Fig 1.

Nasolabial cyst (case 1). A, The axial T1-weighted image shows the lesion beneath the left alar base with a well-circumscribed homogeneous isointensity containing a sedimentation level. B, The axial T2-weighted image shows the homogeneous hyperintensive lesion, in which the sedimentation level is also observed. C, The coronal T2-weighted image shows a bean-shaped homogeneous hyperintensive lesion, which does not expand toward the nasal side but instead expands toward the lateral side.

Fig 2.

Nasolabial cyst (case 2). A, The axial T1-weighted image shows the well-circumscribed lesion with a homogeneous isointensity in the anterior nasal fold. B, The axial T2-weighted image shows the well-circumscribed lesion with a homogeneous hyperintensity. C, The coronal T2-weighted MR image shows the lesion extending toward the nasal cavity along the lateral nasal wall. D, The sagittal T2-weighted MR image shows the expansion of the lesion toward the posterior of the nasal cavity, and the lesion appears as a bean shape because of the anterior edge of the nasal base of the maxillary bone.

Fig 3.

Schwannoma (case 3). A, The axial T1-weighted image shows the rounded well-circumscribed lesion beneath the right alar base. B, The axial T2-weighted images reveals the presence of a homogeneous well-circumscribed rounded lesion beneath the right alar base. The lesion is not attached to the nasal structures. C, The excised specimen shows that the tumor consists of a yellowish jellylike mass encapsulated by thin fibrous tissue. D, Histopathologically, the tumor is composed of proliferating spindle-shaped cells showing a palisaded arrangement and diagnosed as schwannoma Antoni A type (hematoxylin-eosin, original magnification ×20).