Transcript FACIAL PLEXIFORM NEUROFIBROMA MIMING A VASCULAR …

FACIAL PLEXIFORM NEUROFIBROMA
MIMING A VASCULAR MALFORMATION:
I. BRAHIM, A. DARDIK, S. BOURKHIS,
F. BEN AMARA, H. RAJHI, N. MNIF
Department of Radiology
Charles Nicolle Hospital, Tunis, Tunisia
NR22
OBJECTIVES
PLEXIFORM NEVROMA
Describe the clinical and imaging features of
facial plexiform nevroma
 Distinguish them from vascular malformation
and lymphangioma
 Precise their management .
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OBSERVATION
OBSERVATION
CLINICAL HISTORY
A 37-year-old man
 Neurofibromatosis type 1 (von Recklinghausen’s
disease)
 A swelling on the left side of the face
-since 10 years
-had an insidious onset
-it had grown slowly to attain the present size.
 Mild, intermittent dull aching pain in the swelling
since 1 year.
 No history of any regression or any discharge from
the swelling.
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OBSERVATION
CLINICAL EXAM
Extra oral examination : a swelling
-Diffuse on the left side of the face over the jugal
region.
-Measured approximatively 5x5 cm in size
- Indistinct borders.
-Mild tenderness
-Peculiar consistency, soft in most of the areas with
few firm nodular areas, as a 'bag of worms'.
-No pitting
-On auscultation : no bruit
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MAGNETIC
RESONANCE
IMAGING
(MRI) :
AX T1
AX T2 FATSAT
CORO T2
AX T2
MRI IMAGES show :
-hemifacial infiltrating,
ill-defined mass ( pink arrow).
- With homogeneous signal
intensity lesion
- The lesion appeared
isointense in T1W images and
hyperintense in T2W images
with few flow voids (red arrow)
within the lesion
MRI
AX T1 FATSAT
AX T1 FAT SAT GADO
CORO T1 FAT SAT GADO
MRI IMAGES show :
The lesion (pink arrow) extends to the parotid lodge, the infratemporal
fossa, parapharyngeal , masticator, carotid, posterior cervical spaces and
enhanced homogeneously and intensively after Gadolinium injection
DISCUSSION
GENERALITY
PLEXIFORM NEVROMA
Typically
occurs
in
the
setting
of
neurofibromatosis type 1 (NF1) and is included in
the criteria for its diagnosis.
 Considered pathognomanic of NF1.
 May be associated with other stigmata of NF1, or
it may appear as an isolated lesion.
 Is a non metastasizing and locally invasive tumor
 Causes
diffuse
enlargement
of
skin,
subcutaneous tissue and nerve segments of the
affected areas.

GENERALITY
PLEXIFORM NEVROMA
Is a benign nerve tumor resulting from aberrant
growth of the cells of the nerve sheath.
 Originates from the central aspect of the nerve
and involves multiple fascicles.
 Composed of schwann cells, perineurial-like
cells, and fibroblasts .
 Although the fascicles are usually preserved, a
diffusely enlarged, thickened, irregular, and
tortuous nerve is produced.
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MORPHOLOGIC APPERANCE
PLEXIFORM NEVROMA
Is classically compared to a "bag of worms" or
"rosary beads".
 Is a type of multinodular growth of tumor that
forms along nerves plexus or a single large
peripheral nerve.
 Presents a tangle of irregularly sized and
smooth nodules.
 Sausage like enlargement or rope-like alteration
of the affected nerve is seen in single nerve
involvement .

LOCATION
PLEXIFORM NEVROMA
Any cranial or peripheral nerve is susceptible to
PNF formation.
 There is a predilection for larger peripheral
nerves of the face, neck and extremities.
 Motor and sensory nerves from the oculomotor
to the hypoglossal , as well as sympathetic and
brachial plexus involvement in the neck leading
to Horner’s syndrome and motor palsy.
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LOCATION
PLEXIFORM NEVROMA
Can be deep, superficial or a combination of
both.
 Superficial PNF are :
- more common than the deep lesions,
- more likely to be asymmetric in distribution,
with a diffuse or infiltrating morphology, extend
to the skin surface in a reticular and branching
pattern, with smaller fascicles or nodules.
- can be mistaken for venous malformations.
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IN THE HEAD AND
NECK
PLEXIFORM NEVROMA
Can assume rather large proportions and
involve multiple nerves.
 As a result of tumor growth, adjacent bone
resorption and soft tissues hyperplasia can
occur.
 The involved nerves may be very distorted, and
often totally replaced and unrecognizable.
 The destruction of bony landmarks can make
the identification of the facial trunk a delicate
and dangerous task.
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ONSET AND EVOLUTION PLEXIFORM
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NEVROMA
Usually present since birth and may develop throughout
life.
Is typically painless and may go unnoticed until it
become palpable or cause dysfunction of surrounding
structures.
Usually becomes symptomatic at an early age and
exhibits progressive growth.
Increased growth rates occur during childhood or
hormonal changes, such as puberty or pregnancy .
Trauma is thought to be an inciting factor, but no clear
association has been made.
SYMPTOMS
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PLEXIFORM NEVROMA
Is easy to identify on clinical examination because it
feels like a “bag of worms” or “peas in a pod” along
involved nerves
Overlying skin and soft tissue may undergo hypertrophy
as well as pigmentary changes (orange discoloration)
May have dramatic effects on surrounding skin, soft
tissues, and osseous architecture.
The presence of PNF of the head and neck may
interfere with the nasal airway, the eyelids, vision,
mastication, and lip competence, in addition to
producing a cosmetic deformity.
IMAGING
PLEXIFORM NEVROMA
The
most
distinctive
lesion
in
neurofibromatosis is plexiform neurofibroma.
 These lesions may obtain a massive size.
 Appear either well defined (surrounded by a
thick perineurium) or loosely arranged
with limits impossible to define.
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IMAGING: CT SCAN
PLEXIFORM NEVROMA
Nonenhanced CT scans typically reveal low
attenuation masses (3O HU) with ill-defined
margins.
 Low attenuation of the lesions may due to:
-the high water content of the mucinous matrix
-the lipid nature of Schwann cells
-the cystic degeneration and incorporation of
surrounding adipose tissue into the masses.
 Peripheral
enhancement
after
intravenous
administration
of
contrast
material
and
calcifications are nonspecific findings .
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IMAGING: MRI
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PLEXIFORM NEVROMA
On T1-weighted images :
- signal intensity slightly greater than that of muscle.
- hyperintense septations due to myelinated axons
On T2-weighted images :
- markedly increased signal intensity is seen (high water
content )
- hypointense septations corresponding to collagen fibers
- a central zone of lower signal intensity, coined the "target
sign"
-This central inhomogeneity is due to hemorrhage,
fibrosis, necrosis, and/or variations in cellularity
This may prove to be a useful feature in distinguishing
neurofibromas from other soft-tissue tumors .
IMAGING: MRI
PLEXIFORM NEVROMA
Is the modality of choice for the evaluation of
soft-tissue tumors.
 Has demonstrated superiority over CT in the
evaluation of soft tissue tumors.’
 PNF
typically reveals a noncharacteristic
appearance and is often misdiagnosed when a
history of NF1 is unclear.
 When the MRI appearance is typical, it
suggests the diagnosis.
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IMAGING: MRI
PLEXIFORM NEVROMA
Is able to distinguish thickened perineurium
(fibrous tissue) surrounding the plexiform
neurofibroma.
 Its multiplanar capabilities precise volumetric
evaluation of the PNF which is helpful in
delineating the extent of the tumor.
 Its ability to distinguish benign from malignant
neuronal tumors remains poor.
 May not detect osseous invasion .
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DIFFERENTIAL
DIAGNOSIS
PLEXIFORM NEVROMA
•Lymphoma
•Schwannomas
•Neurofibromas
•Malignant peripheral nerve sheath tumors
PNF differ from schwannoma and neurofibroma,
in that the former are unencapsulated and
involve several fascicles rendering their internal
margins almost indistinguishable
 Unfortunately, there is no radiographic study able
to definitively distinguish between them.
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PATHOLOGIC FEATURES PLEXIFORM
NEVROMA
Macroscopic appearance :
-Ropelike : non branching nerves
-Bag of worms : highly branching nerves
 Classified into 2 types:
Nodular (common) / Diffuse (rare)
A
benign nerve sheath tumor,
non
encapsulated, poorly circumscribed that often
extends tortuously along nerves.
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PATHOLOGIC FEATURES PLEXIFORM
NEVROMA
Proliferation of spindle cells from either the
neuroectodermal Schwann cell sheath or
mesodermal fibrous connective tissue.
 A myxoid matrix is typical of PNF however, as
these tumors enlarge, they become more
cellular and collagenous
 PNF cells are usually S-100 positive
(immunohistochemical marker )
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EVOLUTION
PLEXIFORM NEVROMA
Sarcomatous transformation is suggested
when a soft tissue mass becomes symptomatic
: rapid growth and pain.
 Between 5 and 6% of PNF undergo malignant
transformation, known as malignant peripheral
nerve sheath tumour (MPNST).
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COMPLICATION
PLEXIFORM NEVROMA
The immediate clinical problem depends on
location.
 When the lesion involves the upper airway, there
is strider and obstruction early in infancy.
Tracheotomy and removal of all tumor possible
offer the only hope for survival in this group of
patients.
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FOLLOW UP
PLEXIFORM NEVROMA
MRI is ideal for routine follow-up in : no ionizing
radiation and noninvasive,
 Indications for long-term follow-up :
- malignant transformation,
- rapid recurrence after excision
- rapid growth.
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TREATMENT
PLEXIFORM NEVROMA
Indications for surgical intervention (definitive
treatment ):
pain, dysfunction, diagnostic biopsy, and/or suspected
malignancy.
 Radical surgery is unnecessary and usually impossible
to perform because of the extent of the tumor.
 We recommend selective conservative surgical
resection of functionally impairing or cosmetically
deforming masses without the removal of nerves that
control important functions.
 Surgical resection of PNF is complicated by a high rate
of recurrence.
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CONCLUSION
PLEXIFORM NEVROMA
Considered pathognomanic of NF1.
 A benign nerve and locally invasive tumor.
 Classically compared to a "bag of worms" .
 Has predilection for nerves of the neck, face
and extremities.
 MRI is the modality of choice for suggesting the
diagnosis when the apperance is typical and for
the follow-up.
 Selective conservative surgical resection is
recommended.
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BIBLIOGRAPHY
BIBLIOGRAPHY
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Krueger.W, Weisberger.E, Ballaantyme.AJ : Plexiform
Neurofibroma of the head and neck. The American Journal of
Surgery; volume 138, october 1979.
Pablo.R, Esaghi. Nahid : Plexiform Neurofibroma of the pelvis :
CT and MRI findings; Magnetic Resonance Imaging, vol9,
pp463-5,91.
Eoghan E.L, MD,PHD, Navarro : Pediatric Soft Tissue tumors
and Pseudotumors: MR Imaging Features with Pathologic
Correlation, Radiographics2009,10.
Fortman.B, Brian.MD, Urban B : Neurofibromatosis Type 1 : a
Diagnostic Mimicker at CT, Radiographics 2001; 21 :601-12.
Abouachadi .A, Nassih.M, Rzin.A :Le névrome plexiforme orbitotemporal : à propos de 6 cas ,Rev.Stomatol,chir.Maxillofac,
2005,272-5.