Facial nerve venous malformation: A radiologic and histopathologic review of 11 cases

Abstract

Objective The purpose of this article was to provide a combined pathologic and radiologic review of previous pathologically diagnosed facial nerve “hemangiomas” to confirm that these lesions are most characteristic of venous malformations rather than neoplasms. Study Design Retrospective radiologic, clinical, and histopathologic review of all patients with a previous pathologically diagnosed facial nerve hemangioma of the temporal bone who underwent computed tomography or magnetic resonance imaging (MRI) were included. A consensus radiologic review for characteristic features and pathologic analysis was performed. Materials and Methods A panel of 4 neuroradiologists retrospectively analyzed CT and MRI exams for 11 facial nerve hemangiomas and provided a consensus agreement on the characteristic imaging features. Concurrently, two neuropathologists reevaluated archived tissue specimens from these lesions and applied additional immunohistochemical and histochemical stains including D240, CD31, smooth muscle actin (SMA), Verhoeff Van Gieson (VVG) and glucose transporter 1 (GLUT1). Results Lesions were composed of dilated vascular spaces with a simple, CD31‐positive endothelial lining and a smooth muscle component. All lesions were negative for markers found in arterial and lymphatic malformations and infantile hemangiomas. They had characteristic radiologic features previously ascribed to facial nerve hemangiomas. Namely, these lesions are typically T1 isointense or hypointense and T2 hyperintense relative to cerebral cortex and heterogeneously enhance on MRI. Bony canal expansion and erosion, intralesional calcification, and intracranial extension are common. Conclusions On the basis of this radiologic and pathologic review, these lesions are best characterized as venous malformations. Level of Evidence 4

Fibrovascular Tumor-Like Lesions of the Facial Nerve

“…However, the traditional nomenclature that refers to the lesions as "hemangiomas" persists. Venous malformations consist of enlarged venous channels with a single flattened layer of endothelial cells, no appreciable mitotic figures, absent internal elastic lamina, and a smooth muscle component [Benoit et al, 2010;Guerin et al, 2019]. These features were not present in our samples, and neither did they present an organized morphology corresponding to a vascular tumor, in accordance with the current classification of the International Society for the Study of Vascular Anomalies [Wassef et al, 2015;Merrow et al, 2016].…”

A case of a facial nerve venous malformation presenting with crocodile tear syndrome

“…[9] e peak incidence of FNMVs occurs between 30 and 60 years of age slightly more common in females. [6] Most commonly, lesions are reported to be centered on the GG with patients presenting with both progressive and sudden facial paralysis and spasm. [16] Other symptoms include conductive hearing loss, otalgia, pulsatile tinnitus, aural bleeding, and vertigo.…”

“…[8] It has been suggested that the presence of calcification effectively excludes schwannoma from the diagnosis. [6]…”

Intraosseous Venous Malformations of the Head and Neck

“…The more common FN schwannoma may compress the nerve and cause dysfunction, whereas a venous malformation may directly infiltrate the nerve and/or cause a vascular steal phenomenon. 39 Therefore, symptoms such as facial paresis or hemifacial spasm or both are much more common with FN IOVMs than the more prevalent schwannoma. When compared with facial neuritis such as Bell palsy, FN dysfunction in IOVMs is more insidious and progressive and will not spontaneously resolve.…”

“…There is a rarer occurrence elsewhere along the FN, namely at the internal auditory canal or second genu. 39 FN IOVMs often infiltrate beyond the margins of the FN canal and geniculate ganglion, aiding in discrimination from facial nerve schwannoma.…”