Keywords
venous malformation - head and neck - parapharyngeal space
Introduction
Historically, vascular anomalies have been labeled with descriptive terms, according
to the food they resembled (port wine, strawberry, cherry, salmon patch). This imprecise
terminology has caused diagnostic confusion, blocked communication, and even caused
incorrect treatment, as it does not differentiate between various vascular anomalies.[1]
In 1982, a classification was established by the International Society for the Study
of Vascular Anomalies (ISSVA).[2] This classification divides vascular anomalies into vascular tumors and vascular
malformations. Hemangioma is the most common vascular tumor, which usually appears
postnatally, exhibiting rapid growth due to cellular proliferation, followed by inevitable
involution. In contrast, vascular malformations are present at birth and grow proportionally
with the patient. They are subdivided depending on the affected vessel type into capillary,
venous, lymphatic, and arterial malformations.[3]
[4]
Although vascular malformations are one of the most common soft-tissue malformations
of the head and neck, they are relatively rare in the parapharyngeal space.[1] Herein, we describe a case report of barky venous malformation in the parapharyngeal
space with a review of literatures.
Case Report
A 21-year-old man who had no particular self or family medical history experienced
pain in the left mandibular space and referred to a nearby hospital. Physical examination
revealed an elastic, hard, unmovable tumor existing in left mandibular space without
tenderness, which is an abnormal neurological finding. There was no obvious change
of the tumor findings upon increasing venous pressure via Valsalva maneuver.
Magnetic resonance imaging (MRI) was performed and detected a huge tumor located in
the left parapharyngeal space. For additional precise examination and treatment, the
patient was referred to our hospital. Flexible laryngoscopy findings showed nasopharyngeal
submucosal swelling beneath the tumor and no mucosal lesion. Blood chemistry study
showed acceptable limits. Neck ultrasonography revealed a hypoechoic, hypervascular,
and clear marginal tumor located in the submandibular space with partial calcifications.
There were no remarkable inflow or outflow vessels. Contrast-enhanced computed tomography
(CT) scan revealed a bulky tumor with some calcified lesion located in the parapharyngeal
space. The tumor had some enhanced effects in both arterial- and venous-enhanced phases
([Fig. 1]). Additional enhanced MRI showed low signal intensity on T1 and high signal intensity
on T2 and some effects of enhancement ([Fig. 2]). Although fine needle aspiration was performed, bloody drainage was obtained and
it had no epithelial component. Based on these findings, we suspected the tumor to
be a venous malformation. We informed details of the examination findings and suggested
the choice of treatments to the patient and his family: partial resection to obtain
pathological diagnosis, complete resection to obtain total cure, sclerotherapy, laser
therapy, and conservative therapy. Additionally, we communicated surgical complications,
especially massive bleeding, nerve palsy, and postoperative airway obstruction. They
decided on the course of complete resection.
Fig. 1 Dynamic enhanced computed tomography. (A) In arterial enhanced phase, the tumor had no enhanced effect and calcification spot
inside (arrowhead). A branch of facial artery was detected running through the tumor (arrow). (B) In venous enhanced phase, the tumor had some enhanced effects and calcification
spot inside (arrowhead).
Fig. 2 Magnetic resonance imaging (MRI). The tumor was isointense overall on the axial (A) and coronal (B) T1-weighted images. The tumor signal ranged from iso- to hyperintense on the axial
(C) and coronal (D) T2-weighted images. A clear margin from the surrounding tissues is seen (arrowheads), and calcifications were detected as areas of very low signal on both T1- and T2-weighted
images (arrows).
Operation Findings
Although we had configured an S-shaped incision extending the line to midline jaw dissection as occasion arises,
we could obtain a wide surgical view with a simple arcuate skin incision under the
mandible followed by removal of the submandibular gland and cut off the digastric
and stylohyoid muscle. At the back side of the submandibular bone, we found the caudal
side of the tumor. As it had no adhesion, we peeled the tumor from the surroundings
with blind-finger dissection and exposed internal and external carotid arteries in
the deep portion. After recognition of arterial branches and hypoglossal nerve, we
cut off the occipital and maxillary arteries excluded to the caudal side of the medial
pterygoid muscle. As the tumor had shrunk after ligations of the maxillary artery,
we could complete the resection without any complications ([Fig. 3]). After resection, we repaired the disconnected digastric muscle and recognized
the internal and external carotid arteries, jugular vein, and hypoglossal nerve and
then preserved. The sympathetic chain, vagus nerve, accessary nerve, and glossopharyngeal
nerve did not appear in the surgical view. The operation time was 249 minutes, and
intraoperative blood loss was approximately 100 mL.
Fig. 3 Photograph of the operative field after removal of submandibular gland during tumor
resection. Caudal side of the tumor (arrowhead) was located in the parapharyngeal space adjacent to the digastric tendon (arrow).
Pathological Findings
Hematoxylin and eosin staining showed that the tumor contained hyperplasia of vessels,
organizing blood clot, ossification, and hemosiderin deposit. Pathological diagnosis
was venous malformation: cavernous angioma ([Fig. 4]).
Fig. 4 Macroscopic and microscopic images of the tumor. (A) The excised specimen was dark brown in color with sponge-like appearance, and contracted
in size after resection. (B) Hematoxylin and eosin staining of the tumor specimen showed hyperplasia of vessels,
organized blood clots, calcifications, and hemosiderin deposits (arrowheads).
After surgery, the patient was on a good clinical course without trismus and discharged
from the hospital on postoperative day 8. The patient showed no recurrence after 2
years of treatment.
Discussion
Venous malformations are the most common subtype of vascular malformation and represent
44 to 64% of vascular malformations. They can be localized or diffuse and can occur
in more than one body site: extremity (40%), head and neck (40%), and trunk of the
body (20%).[5] Faruque et al reported in a systematic review of 1,143 parapharyngeal space tumors
that a majority (82%) were benign and hemangioma was present in only 11 cases (0.96%).[6] In Japan, Okamoto et al reported on the pathological diagnosis of 76 parapharyngeal
space tumors, and they found that majority were schwannomas (42%) or pleomorphic adenomas
(37%) and there were no venous malformations.[7] There were few reports of venous malformations in the parapharyngeal space. Meanwhile,
Maeda et al reported a case experience with information that they had difficulty in
preoperative diagnosis from image findings.[8]
Venous malformations are characterized by a soft, compressible, no pulsatile tissue
mass and have several forms: cystic, varix-like, dilated vessel-like, and sponge-like
forms.[9] Rapid enlargement may occur in certain situations such as surgery, trauma, infection,
or hormonal changes associated with puberty, pregnancy, or menopause. Departed from
vascular tumor, venous malformations can be confined to one specific area or spread
out, and it can be superficial or deep.[10] Deep cutaneous or intramuscular lesions usually cause discomfort, often in the early
morning on awakening or with exertion. Intraoral venous malformations can bleed, distort
dentition, cause speech problems, and obstruct the upper airway. Thrombosis, swelling,
and pain are common in venous malformations. Only symptomatic malformations or lesions
causing important aesthetic prejudice require treatment.[11]
History and physical examination remain the mainstay of diagnosis, which is made by
clinical assessment. Imaging is reserved to evaluate the depth and extent of the lesion.
Doppler ultrasound (US) is essential in differentiating venous malformations from
other vascular anomalies. They appear as hypoechoic or heterogenous lesions in 80%
of cases.[12]
[13] Anechoic channels can be visualized in less than 50% of cases. Sometimes, isoechoic
thickening of the subcutaneous tissues without a solid mass or discernible channel
is the only feature. Hyperechoic foci with posterior acoustic shadowing are seen in
less than 20% of cases.[12] Although US is traditionally and sill currently used for characterization of vascular
lesions, it is limited by a small field of view, restricted penetration, and operator
dependency. At CT, venous malformations are hypoattenuating or heterogeneous lesions
that enhance slowly and peripherally after bolus injection of contrast material. Phleboliths
are more clearly depicted and fatty components are sometimes demonstrated at CT.[14]
[15] MRI is excellent for defining the extension of vascular malformations and their
relationship to adjacent structures. High-flow arteriovenous malformations and fistulas
contain a signal void, whereas slow-flow venous malformations are usually hypo- or
isointense at T1-weighted imaging and show high signal intensity on T2-weighted images.
Areas of hypointensity related to thrombosis, septation inside, or phleboliths also
can be observed.[16]
[17] Gadolinium-enhanced T1-weighted imaging is useful in evaluating the circulatory
portion of the malformation. As venous malformations with a connection to deep veins
can be a high risk factor of venous clot, delayed phase-enhanced MRI is essential
for establishing a treatment strategy.[18]
Venous malformations that are not causing symptoms do not require treatment. Basic
treatment consists of the use of graded elastic compression stockings or sleeves to
prevent swelling and formation of clot or phlebolith.[12] However, especially in head and neck regions, compression can be adapted for few
cases because of anatomical location. Conservative treatment options are sclerotherapy,
laser therapy, venous embolization, and surgical excision.[19]
[20]
Although sclerotherapy is effective for small marginal lesions that have less complications
than radical surgery for cosmetic aspect, deep and large lesions require performing
the procedure several times to achieve complete and permanent shrinkage.[19]
[20] For patients with extensive venous malformation in the parapharyngeal space, it
is necessary to consider the possibility of airway compromised and systemic complications
depending on the sclerosing agent after the procedure. Laser therapy is similar to
sclerotherapy and it is useful for treating very superficial lesions, such as oral,
tongue, and pharyngeal lesions.[21]
Surgical excision is generally contemplated after sclerotherapy when treatment is
incomplete or when an aesthetic prejudice requires correction. A superior aspect of
surgery is removing all of the abnormal veins and phleboliths. However, surgery also
has complications of massive bleeding, nerve palsy, and cosmetic aspect.[10]
[22] We have to select an adequate treatment strategy for head and neck lesions.
In this case, we suspected the diagnosis of venous malformation based on the examinations.
As it was expected that multiple sclerotherapy would be needed to obtain complete
shrinkage and could be a cause of airway edema, we eliminated sclerotherapy for initial
treatment for this case. As a relatively bulky venous malformation was located under
mucosa in the pharyngeal lesion, we considered laser therapy was inadequate. Fortunately,
we could perform radical resection without complications. As three-dimensional angiographic
CT scans were performed and there were some enhanced effects in the tumor, we did
not select a preoperative angiography to avoid invasiveness of the exam. However,
according to our operation findings, angiography would be useful for detecting feeding
vessel and intravascular embolus even for venous malformation. The vascular malformation
in the head and neck regions should be diagnosed before primary treatment with multimodality
as they are linked to selection of treatment strategy. Additionally, we have to choose
adequate treatment based on the location and conditions of vascular malformation with
certain considerations.
Conclusion
We experienced a unique case of huge venous malformation in the head and neck regions.
As venous malformation in the parapharyngeal space is uncommon and treatment strategies
have not been established, further investigations are required to obtain a definitive
treatment strategy.
