Geniculate ganglion meningioma

Abstract

The geniculate ganglion is an unusual location for an intratemporal/intracranial meningioma. We present a case of meningioma intrinsic to the geniculate ganglion that presented peculiar features on high-resolution computed tomography (HRCT) and magnetic resonance imaging. On HRCT, we found erosion of the geniculate ganglion with enlargement of the facial canal associated with the appearance of some calcifications within the lesion. These latter findings were confirmed at histological examination. In our patient, the T1- and T2-weighted magnetic resonance images had an intermediate signal and a mild hyperintensity, respectively. Although intracranial meningiomas can have calcifications within the mass, none of the cases of geniculate ganglion meningiomas described in the literature presented with calcifications. To our knowledge, our case is the first with this combination. The presence of calcifications led us to suspect a meningioma of the geniculate segment, which was confirmed at histological examination.

Keywords: Geniculate ganglion; facial graft; meningioma; skull base surgery.

Figure 1

(A) Axial HRCT images. The image shows temporal bone erosion at the site of the geniculate ganglion with a subtle high density in the middle with very thin bony spicula in peripheral medial position (arrows). In addition, the facial canal is enlarged. (B) Coronal HRCT images. Enlargement of the fallopian canal.

Figure 2

(A) Axial T1-weighted 3-D magnetic resonance imaging. The mass located in the geniculate ganglion region shows homogeneous isointense signal. The tumor appears to be in a more anterior-medial position with respect to the geniculate ganglion, along the course of the greater superficial petrosal nerve. (B) Axial T1-weighted 3-D magnetic resonance imaging. Intense enhancement postgadolinium. There is also facial nerve enhancement in the geniculate and proximal tympanic segment of the fallopian canal. (C) Parasagittal T1-weighted magnetic resonance imaging postgadolinium. This image obtained in parasagittal plane perpendicular to the tympanic segment of the facial nerve shows completely the nerve. The mass is located in the geniculate ganglion. There is enhancement of the vertical segment of the nerve probably secondary to ischemia and edema. On the right inferior corner of the image, the representation of the parasagittal slices.

Figure 3

Axial T2-weighted 3-D magnetic resonance imaging, slice thickness of 750 μm. In the region of the anterior geniculate ganglion, there is a mass showing mild hyperintensity (arrows).

Figure 4

Numerous vessels and fibrosis, calcified psammoma body (hematoxylin and eosin stain).