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Kaposiform
Hemangioendothelioma (KHE):
This is a vascular tumor associated
with the Kasabach-Merritt phenomenon
(severe coagulopathy due to platelet
trapping and spontaneous bleeding).
These tumors are histopathologically
distinct from the common hemangiomas
of infancy.
KHE
may be present at birth in neonates, or they
can develop in infants within the first few
months after birth.
An ill-defined purpuric mass is a common
presentation. A truncal location is the most
common site. Destructive bone changes in
adjacent bones are common.
Diagnosis:
The MRI findings of Kaposiform
hemangioendothelioma also clearly
differ from those of common infantile
hemangioma. In contrast to common
hemangioma, this neoplastic birthmark
characteristically involves multiple
tissue planes, with cutaneous
thickening, subcutaneous stranding,
and edema. Gradient-echo images may
demonstrate hemosiderin. Superficial
feeding and draining vessels are less
frequent and less prominent than with
common hemangioma. Destructive osseous
changes in the adjacent bones are
common in Kaposiform
hemangioendothelioma, whereas only
some remodeling occasionally occurs in
infantile hemangiomas.
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| Photo#1
shows a relatively small
kaposiform hemangioendothelioma
near the ear. Figure#2
is a catheter arteriogram in
apatient with a large kaposiform
hemangioendothelioma in the
thigh. Figure#3 is a T2
weighted axial MRI image shows
an ill defined infiltrative
appearing kaposiform
hemangioendothelioma lesion in
the upper thigh and buttock
area. |
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1st image is histopathology
of Kaposiform
hemangioendothelioma (Source: PathoPic).
2nd image is a T2 weighted MR image
demonstrating a large inhomogeneous
soft tissue abnormality (tumor) in the
facial area (kaposiform
hemangioendothelioma). This patient
developed Kasabach-Merritt syndrome,
required multiple embolization
procedures.
Treatment: Kaposiform hemangioendothelioma
has a mortality rate of 24%, which is
related to coagulopathy or
complications of local tumor
infiltration. The tumor is associated
with extremely low platelet counts and
markedly decreased fibrinogen levels.
Patients with Kaposiform
hemangioendothelioma need to be
closely monitored for severe
coagulopathy. Pharmacological
treatment regimen is similar to that
of infantile hemangioma depending on
the severity of the condition. Other
treatment alternatives for patients
with kaposiform hemangioendothelioma
are transcatheter
embolization and surgical
excision.
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