Venous vascular malformation of the facial nerve
Venous vascular malformations of the facial nerve, previously known as facial nerve hemangiomas, are rare benign vascular malformations of the facial nerve usually presenting as a facial nerve palsy, which can be rapid onset mimicking a Bell palsy.
As they do not appear to have clinical course, or histological features of hemangiomas, the nomenclature was changed 5.
These lesions typically affect middle aged patients and are very slow growing.
At presentation they are usually ~1 cm in size, and typically cause significant symptoms despite their small size. This is another distinguishing feature from schwannomas which despite larger size often have few symptoms. Typically they present with facial nerve palsy which can be rapid onset mimicking a Bell palsy. Sensory neural hearing loss (SNHL) and tinnitus can also be presentations.
The bony margins are indistinct, as although the malformation is localized it is unencapulated, enabling them to be distinguished from schwannomas, which like schwannomas elsewhere (think jugular foramen lesions) have well defined remodeled margins.
Both capillary and cavernous sub types are identified histologically and both types can be seen within the one tumor.
A variant is the ossifying hemangioma of the facial nerve, which has a distinctive appearance; radiating outwards from its center is a 'spoke wheel' or 'honeycomb' arrangement of ossification.
Reported signal characteristics of the region includes:
- T1: iso or slightly hypo intense
- T2: hyper intense
- T1 C+ (Gd): intense contrast enhancement
Treatment and prognosis
- content pending
Imaging differential considerations include
- 1. Balkany T, Fradis M, Jafek BW et-al. Hemangioma of the facial nerve: role of the geniculate capillary plexus. Skull Base Surg. 1991;1 (1): 59-63. - Free text at pubmed - Pubmed citation
- 2. Friedman O, Neff BA, Willcox TO et-al. Temporal bone hemangiomas involving the facial nerve. Otol. Neurotol. 2002;23 (5): 760-6. Otol. Neurotol. (link) - Pubmed citation
- 3. JD Swatrz, HR Harnsberger "Imaging of the Temporal Bone" Thieme
- 4. Chan EH, Tan HM, Tan TY. Facial palsy from temporal bone lesions. Ann. Acad. Med. Singap. 2005;34 (4): 322-9. Ann. Acad. Med. Singap. (link) - Pubmed citation
- 5. Benoit MM, North PE, McKenna MJ et-al. Facial nerve hemangiomas: vascular tumors or malformations?. Otolaryngol Head Neck Surg. 2010;142 (1): 108-14. doi:10.1016/j.otohns.2009.10.007 - Pubmed citation