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IMAGING FINDINGS OF PERINEURAL
TUMOR SPREAD ALONG PERIPHERAL
BRANCHES OF THE FACIAL NERVE
(CN7)
Submission #: 682
Authors: N Patel , R Beegle , I Schmalfuss
University of Florida College of Medicine, Gainesville, FL
& North Florida/South Georgia Veterans Administration
Purpose
 Imaging findings of perineural tumor spread
(PNTS) along the facial nerve (CN7) main trunk
are well established.
 However, many cancer patients suffer from PNTS
along peripheral branch(es) of CN7.
 Recognition of early PNTS is critical as it is often
resectable, allowing for more favorable patient
outcome.
Objective
 Familiarize the radiologist with the imaging
spectrum of PNTS along the peripheral
branches of CN7 to facilitate early detection.
Approach/Methods:
 Review of the anatomy of the peripheral branches
of CN7 and their relation to the superficial muscular
aponeurotic system (SMAS) of the face.
 Presentation of PNTS along the different peripheral
branches of CN7 illustrating the spectrum of
imaging findings on
 CT
 MRI
Development
 CN7 originates from the hyoid arch (2nd branchial arch)
 Course, branching pattern, and anatomical relationships
of CN7 are established in the first 3 months of prenatal
life with full development reached at age 4.
 During the 8th week of gestation, the temporofacial and
cervicofacial divisions form followed by subdivision into
the 5 major terminal branches.
Five terminal branches of CN7
 Temporal (frontal)
 Zygomatic
 Buccal
 Marginal mandibular
 Cervical
Five terminal branches of CN7
Modification of
Temporal (frontal) branches
 Cross the zygomatic arch to the temporal region:
Modification of
Temporal (frontal) branches
 Supply muscles that wrinkle the forehead, close
the eyelids and wiggle the ear
 Auricularis anterior and superior muscles
 Frontalis, orbicularis oculi, procerus & currugator
supercilii muscles via the anterior branches
Zygomatic branches
 Run along anterior aspect of the zygomatic bone to
lateral and inferior orbit:
Modification of
Zygomatic branches
 Supply the muscles that close the eye, move
the nose, and raise the corners of the mouth:
 Zygomaticus major and minor muscles
 Orbicularis oculi muscle
 Levator labi superioris muscle
 Levator labii superioris muscle
 Depressor and compressor nasi muscles
 Dilator naris muscles
Buccal branches
 Extend horizontally along the cheek to face midline:
Modification of
Buccal branches
 Buccal branches of CN7 are larger in size than the
other CN7 terminal branches.
 Supply the muscles below the orbit and around
the mouth:
 Superior part of the orbicularis oris muscle
 Buccinator muscle
Marginal mandibular branch
 Courses anteriorly along the mandibular ramus and
body:
Modification of
Marginal mandibular branch
 Supplies the muscles of the lower lip and chin:
 Quadratus labii inferioris muscle
 Lower part of the orbicularis oris muscle
 Triangularis muscle
 Mentalis muscle
Cervical branch
 Extend anteriorly to form a series of arches along
the lateral suprahyoid neck:
Modification of
Cervical branch
 Supplies
 Platysma musculatur
 Depressor anguli oris muscle
 One branch descends to join the cervical
cutaneous nerve from the cervical plexus.
Pathology:
 PNTS along CN7 is most commonly related to
cutaneous squamous cell carcinoma or primary
parotid gland malignancies.
 PNTS often extends in retrograde direction;
however, antegrade growth can also be present
but is often overlooked.
Clinical presentation:
 Depends upon involved peripheral branch of CN7

Prabhu RK et al. Evaluation of facial nerve function following surgical approaches
for maxillofacial trauma. Ann Maxillofac Surg 2012;2:36-40.
Clinical presentation:
Inability to wrinkle
forehead & eyebrow
Drooping eye &
inability to close eye
No muscle tone &
inability puff cheeks
Drooping mouth &
inability to smile
Imaging findings of PNTS along
peripheral branches of CN7
 Thickening along the SMAS of the face, platysma of
the upper neck, or within the superficial parotid
gland
 Enhancement along the SMAS of the face,
platysma of the upper neck, or within the
superficial parotid gland
Case 1:PNTS along temporal
branch of CN7
76 year old male with skin lesion in the lateral
upper cheek region on the right presents with
inability to wrinkle the forehead.
Biopsy reveals squamous cell carcinoma.
Imaging is performed for staging purposes.
Case 1:PNTS along temporal
branch of CN7
Post contrast CT image shows thickening of SMAS superior to
the right zygomatic arch (arrow) when compared to its normal
appearance on the left (arrow).
T1
GdT1FS
T1 images confirm the thickening of the right SMAS (arrow) when
compared to its normal appearance on the left (arrow) . There is
associated with marked enhancement on the Gadolinium T1 fat
suppressed (GdT1FS) image (arrow).
The CT & MRI findings are consistent with PNTS along
the temporal branch of CN7 and explain the patient’s
inability to wrinkle the forehead.
Case 2:PNTS along zygomatic
branch of CN7
65 year old male with right preauricular skin
lesion presents with inability to completely
close his right eye.
Biopsy reveals squamous cell carcinoma.
Imaging is performed for staging purposes.
Case 2:PNTS along zygomatic
branch of CN7
Post contrast CT image demonstrates preauricular thickening of the
SMAS at the level of the zygomatic arch (arrow) that extends in
antegrade fashion from the infiltrating skin lesion (arrow). Normal
SMAS is seen on the left (arrow).
FST2
GdT1FS
MRI images confirm thickening of the right SMAS (arrow) with marked
edema on fat suppressed T2 (FST2) and enhancement on the GdT1FS
images that extends in antegrade fashion from the deeply infiltrating
skin lesion (arrow). Normal appearing SMAS is seen on the left (arrow).
The CT & MRI findings are consistent with PNTS along the
zygomatic branch of CN7 and explain the patient’s inability
to close the eye.
Case 3:PNTS along zygomatic and
buccal branches of CN7
69 year old male with right cheek skin lesion
presents without symptoms of facial paralysis.
Biopsy reveals squamous cell carcinoma.
Imaging is performed for staging purposes.
Case 3:PNTS along zygomatic and
buccal branches of CN7
T1
GdT1FS
*
*
T1 & GdT1FS images at the level of mid maxillary sinus show the right cheek
cancer (*) with thickening of the SMAS posterior to the lesion (arrow) and
enhancement along the SMAS anterior to the mass (arrow) when compared
to the normal side (arrow).
These findings are consistent with antegrade & retrograde
PNTS along the buccal branch of CN7.
Case 3:PNTS along zygomatic and
buccal branches of CN7
T1
GdT1FS
T1 & GdT1FS images at the level of zygomatic arch show subtle thickening
and more apparent enhancement of the SMAS (arrows) superior to the
cheek mass (not shown) when compared to the normal side (arrow).
These findings are consistent with antegrade & retrograde
PNTS along the zygomatic branch of CN7.
Case 4:PNTS along buccal
branches of CN7
70 year old female with biopsy proven facial
squamous cell carcinoma presents with recent
inability to play her trumpet.
Imaging is performed for staging purposes.
Case 4:PNTS along buccal & marginal
mandibular branches of CN7
Post contrast CT image shows marked thickening of the right
SMAS at the level of the lower maxilla (arrows) when compared to
the normal other side (arrows).
These findings are consistent with PNTS along the
buccal branch of CN7.
Case 4:PNTS along buccal & marginal
mandibular branches of CN7
m
*
m
*
Post contrast CT images reveal a mass (*) infiltrating the right
mandibular body (m) and subtle thickening of the SMAS posterior
to it (arrows) when compared to the normal side (arrows).
These findings are consistent with PNTS along the
marginal mandibular branch of CN7.
Take Home Points:
 Look for thickening /enhancement of SMAS around a mass to
suggest the diagnosis of PNTS
 Changes might be subtle.
 Comparison with the normal side may be helpful.
 PNTS can occur in antegrade and/or retrograde fashion.
 Buccal & zygomatic branches are most often affected by PNTS
 No cases of PNTS along the cervical branch of CN7 have been
published or seen in our practice .
 30% of patients with PNTS are asymptomatic  Always look
for it!
Summary/Conclusion:
 After reviewing this educational exhibit, the radiologist
should be familiar with the spectrum of imaging findings of
PNTS along peripheral branches of CN7 and be able to
suggest such a diagnosis with a higher level of confidence.
 Early detection of this type of PNTS is critical to allow for
early surgical intervention and more favorable outcome.
References:
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Caldemeyer KS, Mathews VP, Righi PD, Smith RR. Imaging features and clinical
significance of perineural spread or extension of head and neck tumors.
Radiographics 1998;18:97–110.
Galloway TJ, Morris CG, Mancuso AA, Amdur RJ and Mendenhall WM. Impact of
radiographic findings on prognosis for skin carcinoma with clinical perineural
invasion. Cancer (2005), 103: 1254–1257.
Gupta S, Mends F, Hagiwara M, Fatterpekar G, Roehm PC, Imaging the Facial
Nerve: A Contemporary Review. Radiology Research and Practice, vol. 2013, Article
ID 248039, 14 pages.
Marieb E, Koehn K. Human Anatomy & Physiology. Pearson; 9 edition (6 Jan. 2012).
Nemec SF, Hemeth AM, Czerny C. Perineural tumor spread in malignant head and
neck tumors. Top Magn Reson Imaging. 2007;18(6):467–71.
Prabhu RK, Sinha R, Chowdhury SR, Chattopadhyay PK. Evaluation of facial nerve
function following surgical approaches for maxillofacial trauma. Ann Maxillofac
Surg 2012;2:36-40. [image for branch clinical testing]
Raghavan P, Mukherjee S, Phillips CD. Imaging of the facial nerve. Neuroimaging
Clin N Am. 2009 Aug;19(3):407-25.
Schmalfuss IM, Tart RP, Mukherji S, Mancuso AA. Perineural tumor spread along the
auriculotemporal nerve. AJNR Am J Neuroradiol 2002;23:303–311.
Williams LS, Mancuso AA, Mendehall WM. Perineural spread of cutaneous
squamous and basal cell carcinoma: CT and MR detection and its impact on
patient management and prognosis. Int J Radiation Oncol Biol Physics
2001;49:1061–1069.