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Lymphatic malformations (cystic hygroma
or lymphangioma) are usually apparent in
young children. These lymphatic
birthmarks appear in various forms, including as
localized small lesions, or in the
diffuse involvement of an extremity or
particular body part or organ system.
lymphatic malformations (cystic hygroma
or lymphangioma) are usually classified
as microcystic, macrocystic, or mixed.
The medical term cystic hygroma, which
was commonly used for macrocystic
lymphatic malformatins located in the neck, is no longer used
in modern medical terminology. Most
lymphatic malformations (approximately
75%) occur in the cervicofacial region.
The overlying skin can be healthy, or it
may have tiny characteristic vesicles.
| Cervicofacial
lymphatic malformations (lymphatic
birthmarks) may be associated with the
overgrowth of the mandibular body.
Lymphatic malformations of the floor of the mouth and tongue are
usually characterized by vesicles,
swelling, and bleeding. In most cases,
the airway is involved to some degree.
Lymphatic malformations of the orbit typically cause
proptosis (sudden proptosis is usually
due to intralesional bleeding), which
may require surgical or interventional
decompression to save the optic nerve.
Mediastinal lymphatic malformations often accompany cervical
lymphatic malformations (cystic hygromas)
and/or axillary lymphatic malformations
(lymphatic birthmarks).
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Lymphatic
malformations in an
extremity can cause diffuse or localized
swelling with soft-tissue and skeletal
overgrowth. When located in the pelvis,
lymphatic malformations or lymphatic
birthmarks are usually associated with bladder
outlet obstruction, constipation, or
recurrent infection. Disappearing bone
disease (Gorham-Stout syndrome) is a
rare disease entity that is considered
an lymphatic malformation (birthmark) with progressive
osteolysis. Please click here
to see a detailed article on
lymphangiomatosis (PDF format).
Diagnosis:
Most cases are clinically obvious and
require no imaging studies for
diagnosis. However, MRI is particularly
useful to fully evaluate this
abnormality. Interestingly, cysts in
microcystic lymphatic malformation or a
lymphatic birthmark are usually too small to
identify on images; therefore,
microcystic lymphatic malformations may easily be confused
with other solitary masses or
soft-tissue abnormalities. The MRI
findings of lymphatic malformation
(cystic hygroma or lymphatic birthmark) are characteristic. The
cysts have low signal intensity on
T1-weighted MRI and marked
hyperintensity on T2-weighted MRI.
Fluid-fluid levels within the cysts are
common. Similar to venous malformations
(cavernous hemangioma), high-flow
vascular signal voids and flow-related
enhancement are not expected in
lymphatic malformations.
After the intravenous administration of
contrast material, the lesion or
lymphaticbirthmark may show
mild enhancement of the septae and
walls, which creates a characteristic
enhancement pattern (rings and arcs).
Most LMs, however, are not enhancing;
this is the most apparent difference
between lymphatic malformation
(lymphatic birthmark) and venous
malformation (cavernous hemangioma) on
MRI. Click here
to go to a related article (Appropriate
Diagnostic Workup for Birthmarks).
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| MR
images of LM lesions. 1st
lesion is in the tongue and
tongue base. 2nd lesion is
simply a large cystic lesion
with a fluid-fluid level,
which is due to bleeding
into the lymphatic cystic
lesion. The 3rd
image is a radiograph after contrast
injection into the lymphatic
malformation (cystic hygroma). This
is commonly performed before any
sclerosant substance injection. |
With
microcystic lesions, the enhancement
pattern may appear to be more solid
compared with that of macrocystic LMs,
and it may be confused with other
soft-tissue abnormalities. Occasionally,
enhancement of the cysts may be seen
after LMs are treated (with either
surgical or intralesional injection) or
in mixed lymphaticovenous malformations.
Large and/or anomalous venous channels
are often seen. In Gorham-Stout syndrome
(disappearing bone disease), bone
lesions are best demonstrated with
T2-weighted spin-echo images. MRL shows
the dilated or interrupted lymphatic
channels, especially those in the limbs.
The characteristic imaging feature of
macrocystic LM of the neck (cystic
hygroma) is a single large cyst just
posterior to the parotid gland, with or
without septae. These macrocystic LMs
usually demonstrate fluid-fluid levels.
Pharyngeal cleft cysts should be
carefully excluded. LMs of the floor of
the mouth and tongue are usually
microcystic and diffuse, and they
usually have minimal or no contrast
enhancement. In the extremities, LMs may
be similar to VMs, particularly on
T2-weighted images, although no contrast
enhancement is expected in LMs. Contrast
enhancement is typical of VMs.
Angiographically, LMs are usually
avascular lesions, although a prominent
capillary blush can be seen in lesions
associated with bleeding. Anomalous and
prominent veins, however, are frequently
present. Although conventional contrast
lymphangiography is rarely performed
today, it is useful in determining the
precise location of lymphatic leaks.
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First
2 images demonstrating bone changes that
may be seen with lymphatic malformation
involvement.1st image is an axial CT
image showing multiple bone defects in
the right hip bones. 2nd image is a T2
weighted MR image showing deformed
pelvic bones with diffuse lymphatic
involvement. 3rd image is a subtraction
radiograph obtained during an iodinated
contrast material injection into a
lymphatic malformation that is located
in the orbit.
Treatment:
Most macrocystic cystic hygroma or
lymphatic malformations can be easily
treated with sclerotherapy.
Some cystic hygroma lesions or microcystic or
mixed lymphatic malformation lesions can
be treated
surgery.
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