Pediatric Clinics of North America - CIPERJ

CARE OF PATIENTS WITH VASCULAR ANOMALIES
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histologically as KHE or TA [23,24]. KHEs and TAs have a different
clinical profile from hemangiomas with a predilection for the upper trunk,
extremities, thigh, sacrum, or retroperitoneum. They are warm, firm, indurated
purpuric lesions. MRI scans show that these lesions invade the
skin and subcutaneous fat and muscle. They usually are focal but some
reports describe lymph node spread. These tumors can be associated
with what now is called Kasabach-Merritt phenomenon (KMP), which includes
an enlarging vascular lesion, profound thrombocytopenia, microangiopathic
hemolytic anemia, and a mild consumptive coagulopathy. The
phenomenon is associated with a mortality rate as high as 20% to
30%. KHE and TA not always are associated with KMP [25], but it is
exactly the coagulopathy seen in KMP that causes morbidity and mortality
in patients who have these lesions. The resulting profound thrombocytopenia
and hypofibrinogenemia cause the most serious hemorrhagic
complications.
Several therapies are reported for the treatment of these lesions but
none is uniformly effective. Therapies include the systemic use of corticosteroids,
interferon, antifibrinolytic agents, and chemotherapy, including
vincristine (VCR), cyclophosphamide, and actinomycin [26–28]. These lesions
are challenging to manage as their clinical presentation and response
to therapy vary greatly. Clinical response can be subtle and take months
to occur. Some lesions remain present for years after resolution of the
KMP, leading to other morbidities, such as orthopedic anomalies and
chronic pain [29]. Cincinnati Children’s Hospital Medical Center has a clinical
registry open to prospectively investigate the clinical course of these
lesions [30]. As discussed previously, KHEs and TAs should not be confused
with hemangiomas and always require supervision by a multidisciplinary
team.
Medical management of hemangiomas
The proper management of hemangiomas is based on size, location, presence
of complications at the time of diagnosis, patient age, and estimated
growth rate [31].
Indications for immediate treatment include interference with vital structures,
the possibility of permanent scarring, large facial hemangiomas, and
ulcerative hemangiomas. Corticosteroids continue to be first-line therapy for
hemangiomas, with response rates varying between 70% and 90% [32,33].
The mechanism of action of corticosteroids remains poorly understood
but is believed to include an antiangiogenic effect that decreases endothelial
cell proliferation and causes endothelial cell apoptosis. Hasan and colleagues
[34] studied the histologic and molecular changes in proliferating
hemangioma after steroid therapy and found increased numbers of mast
cells, decreased transcriptional expression of cytokines, and enhanced transcription
of mitochondrial cytochrome B gene.