TITLE: Congenital Vascular Malformations
SOURCE: Grand Rounds Presentation, UTMB, Dept. of Otolaryngology
DATE: December 21, 2006
RESIDENT PHYSICIAN:
FACULTY PHYSICIAN:
SERIES EDITORS: Francis B. Quinn, Jr., MD and Matthew W. Ryan, MD
"This
material was prepared by resident physicians in partial fulfillment of
educational requirements established for the Postgraduate Training Program =
of
the UTMB Department of Otolaryngology/Head and Neck Surgery and was not
intended for clinical use in its present form. It was prepared for the purp=
ose
of stimulating group discussion in a conference setting. No warranties,
either express or implied, are made with respect to its accuracy, completen=
ess,
or timeliness. The material does not necessarily reflect the current or past
opinions of members of the UTMB faculty and should not be used for purposes=
of
diagnosis or treatment without consulting appropriate literature sources and
informed professional opinion."
Vascular Malformations
“Vascular malformation” is a generalized t=
erm
used to describe a group of lesions, present at birth, formed by an anomaly=
of angiovascular or lymphovascular<=
/span>
structures. There has been historical confusion over which lesions should be
included, or excluded, from the category of vascular malformation, as well =
as
over a suitable classification scheme within the category. Virchow, and his
student, Wegener, in 1880, first separated vascular lesions into angiomas and lymphangiomas. They
classified these as simplex, cavernosum, or
Hemangiomas
Hemangiomas are usually not
present at birth, but become apparent during the first few weeks of life. T=
his
appearance is usually followed by rapid progression during the first two ye=
ars
of life, followed by slow involution. Vascular malformations, on the other
hand, usually are present at birth. They then grow proportionately with the
child, showing no signs of spontaneous resolution. On a cellular level,
Vascular malformations, now clearly differentiated fro= m hemangiomas, are described and classified according to their major vascular component. The major categories are lymphatic malforma= tion, capillary malformation, venous malformation, and arter= iovenous malformation. Although these categories are helpful for description, many malformations contain elements from more than one type, thus being describe= d as mixed lesions. Burrows, in conjunction with Mulliken, in 1983, further described malformations as either high flow , having a connection to the arterial or capillary system or low flow, having a connec= tion to the venous or lymphatic system.
Whereas high-flow vascular anomalies, such as arteriovenous fistulas and arteriovenous
malformations, are adequately addressed by means of transarterial embolization,
low-flow malformations found to be solitary or combined in
capillary, venous, or lymphatic vessels are successfully treated
with sclerotherapy. In 1988, the
Lymphangiomas
Diagnosis of lymphatic malformations is made using phy= sical examination, aided by radiographs. Numerous non-invasive and invasive radiologic studies aid in diagnosis. Noninvasive stud= ies include MRI, duplex ultrasound, whole body blood pool scintigr= aphy, transarterial lung perfusion scintigraphy, lymphoscintigraphy, and CT scan. 3 non-invasive tests are sufficiently accurate and obviate the need for invas= ive studies.
Invasive procedures, such as traditional arteriography a= re usually reserved for treatment planning. Ultrasound is generally the initial test performed. It is readily available, inexpensive, and can give the physician an idea on the extent of the lesion.
More detailed information is gleaned from MRI studies.= Studies should include T1- and T2-weighted spin-echo imaging in multiple planes, fat-saturated T1-weighted imaging with the intravenous administration of a gadolinium-based contrast agent, and gradient-recalled echo (GRE) imaging. T2-weighted images are used mainly to evaluate the extent of the abnormality.GRE images are used to identify the hemodynamic nature of the condition (high- vs low-flow lesions); and contrast-enhanced images ar= e used to determine the extent of the malformation and to distinguish low-flow vascular anomalies (venous malformation versus lymphatic malformation). For= any vascular anomaly, the basic approach is first, to evaluate fat-suppressed T2-weighted images to determine the extent of the anomaly, and second, to evaluate the GRE images to decide whether the anomaly is a high-flow lesion= .
If the anomaly is a low-flow lesion, arteriovenous malformation, arteriovenous fistula, and hemangioma can be excluded from the differential diag= nosis. Low-flow vascular anomalies (venous malformation, lymphatic malformation, capillary-lymphatic-venous malformation) can be further differentiated on t= he basis of their morphologic appearances and contrast-enhancement patterns. If the anomaly has no contrast enhancement or a minimal degree of peripheral contrast enhancement (rings and arcs), lymphatic malformation should be considered foremost in the differential diagnosis. If the anomaly has easily noticeable patchy areas of contrast enhancement, venous malformation should= be suspected. If the lesion is a high-flow anomaly,
In hemangiomas, fast-flow = vessels are usually at the periphery of the mass, and the mass usually enhances homogeneously. A mass lesion is not expected in an art= eriovenous malformation. If there are any remaining questions, the high-flow nature of= an arteriovenous malformation can be easily confirmed wi= th Doppler examination, which reveals high-flow, low-resistance arteries and an arterialized waveform in the draining veins.
Lymphatic malformations generally are documented at bi= rth. The microcystic variant, or lymphangioma, presents as clusters of vesicles on the buccal mucosa, tongue, and conjunctiva. The vesicles can be clear, red or black as= a result of microscopic bleeding. Macrocystic les= ions, or cystic hygromas, are often located below the= level of the mylohyoid muscle and present as cervical cystic swelling, often with the overlying skin having a bluish hue. Microcystic forms tend to be associated with adjacent= bone and soft tissue hypertrophy. CT Imaging reveals an iso= dense mass that obscures tissue planes. Macrocystic f= orms are less invasive and appear as cystic structures with sharp demarcations o= f loculations and ring enhancement. Diagnosis of these malformations can be aided by staining for vascular endothelial growth fact= or receptor 3, which is found within the endothelial cells.
Treatm= ent
Lymphatic malformations are treated with either sclerotherapy or surgical resection. Drainage of these lesions results only in temporary shrinkage. Sclerothe= rapy is accomplished with ethanol, sodium tetradecyl sulfate, doxycycline, or OK-432 (a killed strai= n of group A Streptococcus pyogenes) Macrocystic lesions are ideally removed in one proced= ure, because repeated excisions are complicated by fibrosis and anatomic distort= ion Microcystic lesions are often difficult to resect, because there are no distinct tissue planes b= etween the malformed and normal structures. Repeated procedures are necessary, and= complete removal is almost impossible. In planning such a procedure, restrictions should be set for the extent of dissection. The most common complication of resection in the neck= is nerve palsies.
Venous Malformations
Venous malformations (VM) account for 2/3 of all vascu= lar malformations. There are designated as low-flow lesions. Venous malformations are present at birth, grow proportionately with the child, and often enlarge du= ring puberty. VMs present in a spectrum, ranging fro= m an isolated skin varicosity or localized spongy mass to complex lesions infilt= rating various tissue planes&= nbsp; They are common in the skin and subcutaneous tissue of the he= ad and neck region. They may present in skeletal muscle, most commonly in the = intramasseteric area. VMs= may also occur in the craniofacial skeleton, and are most commonly in the mandi= ble, less frequently in the maxilla, and rarely in the nasal and cranial bones. =
Diagnosis
Mandibular venous anomalie=
s can
present with increased mobility of the teeth, expansion of the buccal cortex, or spontaneous bleeding. The overlying=
skin
may be normal, or it may exhibit a bluish tinge caused by involvement of the
dermis. Intraorbital VMs
cause expansion of the orbital cavity and can cause exophthalmia when the h=
ead
is dependent and enophthalmia when the patient =
is
upright. The VM is a s=
oft,
compressible nonpulsatile mass with rapid refil=
ling.
Expansion will occur on compression of the jugular vein or Valsalva's
maneuver or with the head in a dependent position. Sluggish flow and stasis
lead to phlebothrombosis, which presents clinic=
ally
as recurrent pain and tenderness. Phleboliths c=
an
appear in patients as young as 2 years of age. Characteristic
The plain radiographic appearance of an intraosseous
VM demonstrates a localized hypolucency with a
honeycombed or soap bubble appearance. Profile or tangential films s=
how spicules of bone radiating in a sunburst pattern. MRI=
is
the most useful radiographic study soft tissue VM. They are T2-h=
yperintense
lesions and differ from LMs by the presence of
contrast enhancement of the contents of the vascular spaces. Phleboliths or thrombi can be seen as signal voids.
Treatment
Treatment of VM is based on the location, appearance, = and complications such as pain, bleeding, and associated functional problems. T= he treatment options are sclerotherapy and resecti= on. Sclerotherapy is potentially dangerous and requires t= he skills of an experienced interventional radiologist. A small cutaneous or oral mucosal VM can be injected with an = agent such as sodium tetradecyl sulfate; for larger <= span class=3DSpellE>VMs, ethanol (100%) is used. Often, multiple sclerotherapy sessions are needed because of the prop= ensity for recanalization and recurrence. Local complications include blistering, full-thickness cutan= eous necrosis, and nerve damage. More severe and systemic complications include = hemolysis, renal toxicity, and cardiac arrest. Numerous papers have been published concerning sclerotherapy for venous malformations In 2005 Boll published a study in Radiology, describing MR-guided sclerotherapy of low flow vascular malformations with ethanolamine. In this study, patients with lesions of the head and neck presented with chief complaint of either bleeding into oral cavity or cosmetic deformity.
After therapy, all patients reported resolution of ble=
eding
and an improvement in cosmetic appearance. In this study of 15 patients, no
severe complications—such as skin necrosis, neuropathy, mu=
scle
atrophy and contracture, deep venous thrombosis, pulmonary embol=
us,
disseminated intravascular coagulation, or cardiopulmonary colla=
pse—were
observed. Surgical resection is indicated, usually after completion of sclerotherapy for large or symptomatic VMs.
Under most circumstances, total extirpation is impossible, and a subtotal
resection is indicated to reduce bulk and improve contour, function, or rel=
ieve
pain. VMs of the jaw, nasal bones, and zygoma are managed by curettage and packing with a
Capillary Malformations
Capillary malformations are present at birth and change
slowly with time to a purple color in adulthood. CMs
are often associated with hypertrophy of the soft tissue and underlying
skeleton and when in the cervicofacial area may=
be
associated with enlargement of the affected lip, gingi=
va,
maxilla, and mandible. Skeletal overgrowth may not be obvious at birth, but
progress in childhood. Patients with capillary staining of the ophthalmic (V1) and
maxillary (V2) dermatome. may have Stur=
ge-Weber
syndrome, with capillary, venous, and arteriovenous
anomalies of the leptomeninges.[46] This anomalous circulation is
responsible for the progressive degeneration and atrophy of the cerebral
hemispheres causing seizures, contralateral
Treatment
Tunable flashlamp pulsed-d= ye laser (585-nm wavelength) pulsed dye laser is widely regarded as the optimum trea= tment for these disfiguring lesions. An overall improvement with lightening of the stain and flattening of the area is expected in approximately 70% of patien= ts Theories exist on reasons for persistence of lesions after laser thermolysis. In 2005, Sivarajan et al. published a study investigating changes in capillary depth and diameter, within lesionsI, that occur with laser therapy. Their findings show that persistent vessels in capillary malformations are after treatment are = deeper and narrower than those in untreated lesions. The authors of this study sug= gest that since depth and diameter are crucial to the most effective wavelength = and pulse duration, respectively, of a therapeutic laser, adjusting these laser parameters for treating resistant lesions may be effective. In selected cas= es, older patients, there may be a consideration for excision in the esthetic facial units. The potential problems after excision and grafting include scarred hypertrophy at the junction of the graft and normal skin and unpred= ictable pigmentation within the skin graft itself. Soft tissue and skeletal hypertr= ophy often require surgical correction. Orthognathic= and orthodontic procedures are required for maxillary and = mandibular overgrowth.
Arteriovenous Malformati= on
Arteriovenous malformation=
(AVM)
is usually noted in birth, but is rarely symptomatic during infancy. Many
lesions have a warm erythematous blush and can =
be
mistaken for "hemangioma" or mislabel=
ed as
a "port-wine stain." Local infection, trauma, hormonal changes, a=
nd
puberty may trigger expansion and often manifest during childhood, adolesce=
nce,
or even adulthood. Local warmth, thrill, and a bruit confirm the diagnosis.
Shunting of blood diminishes nutritive flow, which may result in skin necro=
sis,
ulceration, bone destruction, and bleeding. The patient often seeks managem=
ent
for swelling, pain, or sudden hemorrhage. The diagnosis is confirmed by
Treatment
Rarely is treatment indicated for an asymptomatic AVM.= Once the diagnosis is made, the child should be closely followed every 6 months = or yearly. However, in rare instances and after careful consideration, resecti= on may be performed for a well-localized, Stage I AVM. Often intervention shou= ld be delayed until there are signs and symptoms of pain, bleeding, ulceration, infection, or concern for endangering vital structures (Schobinger stage II–III). There is no place for ligation or proximal embolization of feeding vessels. Th= is will lead to rapid recruitment of flow from nearby arteries and denies acce= ss for embolization. Supersel= ective arterial or retrograde venous embolization may = have a role in palliation, or it may be used as primary therapy for surgically inaccessible AVM. The = only therapy that carries may hope for long-term success is total resection of t= he tissue involved with the AVM. Leaving behind residual and dormant anomalous channels only invites further collateral formation, shunting, and expansion= .
Preoperative superselective embolization will not diminish the extent of the rese= ction. However, it will minimize intraoperative bleedi= ng. Embolization must be in the nidu= s, or epicenter, of the AVM and is carried out 24 to 72 hours before the resec= tion. Often a two-team approach (for resection and reconstruction) is useful for these lesions. The critical decision is how extensive the resection must be= to include all of the involved tissue. Reconstruction often necessitates closu= re and soft-tissue replacement with microvascular = tissue transfer. Given proper indications and with careful planning, extensive resection may be justified.
Conclusion
Much knowledge is now known about the radiographic appearance, natural history, and response to treatment of vascular malformations. This knowledge now allows clinicians, using a team approach = to form appropriate treatment plans. Clinicians in private practice who suspect their patient has a vascular malformation should refer them to a tertiary center where a multidisciplinary team can treat the malformation successful= ly, while minimizing complications.
Bibliography
Boll DT.
Jian XC. Surgical management of <= span class=3DSpellE>lymphangiomatous or lymphangiohe= mangiomatous macroglossia. [Journal Article] Journal of Oral & Maxillofacial Surgery. 63(1):15-= 9, 2005 Jan.
Kakimoto N. Tanimoto K. <=
span
class=3DSpellE>Nishiyama H. Murakami S. Furukawa S. Kreiborg
S. CT and MR imaging features of oral and maxillofacial hemangioma
and vascular malformation. [Journal Article] European J=
ournal
of Radiology. 55(1):108-12, 2005 Jul.
Lee BB. Kim= YW. Seo JM. Hwang JH. Do YS. Kim DI. Byun HS. Lee SK. Huh SH. Hyun WS. Current concepts in lymphat= ic malformation. [Review] [44 refs] [Journal Articl= e. Review] Vascular & Endovascular Surgery. 39(1):67-81, 2005 Jan-Feb.
Lee BB.
Critical issues in management of congenital vascular malformation. [Review]=
[40
refs] [Journal Article. Review] Annals of Vascul=
ar
Surgery. 18(3):380-92, 2004 May.
Puig S. Casati B. Staudenherz A. Paya K. Va=
scular
low-flow malformations in children: current concepts for classification,
diagnosis and therapy. [Review] [92 refs] [Journal Arti=
cle.
Review] European Journal of Radiology. 53(1):35-45, 2005 Jan.
Reza Rahbar= Trevor J. McGill John B. Mulliken. Vascular Tumors and Malformations of the Head and Neck [Book Chapter] Cummi= ngs: Otolaryngology: Head & Neck Surgery, 4th ed., 2005
Sivarajan V. Mackay IR. Noninvasive in vivo assessmen=
t of
vessel characteristics in capillary vascular malformations exposed to five
pulsed dye laser treatments. [Journal Article] Plastic =
&
Reconstructive Surgery. 115(5):1245-52, 2005 Apr 15.