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Management of Congenital Vascular Lesions of the Head and Neck

Management of Congenital Vascular Lesions of the Head and Neck

ABSTRACT: Congenital vascular lesions are often misdiagnosed and, for the most part, left untreated. The absence of a uniformly accepted classification of these lesions and confusion over their natural history are partly responsible. A new classification of these lesions recognizes two distinct groups of lesions, hemangiomas and vascular malformations. Hemangiomas are usually not present at birth, proliferate during the first year of life, and then involute. In contrast, vascular malformations are always present at birth, never proliferate, and never involute. Knowledge of this classification system will facilitate the diagnosis of these lesions and lead to appropriate, individualized treatment. [ONCOLOGY 9(10):989-1004, 1995]

Introduction

Until recently, the treatment of congenital vascular lesions lacked
a protocol. This stemmed, in part, from the absence of a uniformly
accepted classification and the lack of a clear understanding
of the natural history of these lesions. Further compounding the
problem was the widely held notion that, given time, most such
lesions would spontaneously resolve. Congenital vascular lesions
were therefore misdiagnosed and, for the most part, left untreated.
The plight of these unfortunate patients led them from physician
to physician in search of help.

The renaissance began with a (biologic) classification first proposed
by Mulliken and Glowacki [1]. They dispensed with the old, often
confusing terminology and replaced it with a clear, concise set
of terms and definitions. Mulliken and Glowacki recognized two
entirely distinct groups of congenital vascular lesions: hemangiomas
and vascular malformations (Table 1). They defined hemangiomas
as lesions that were usually not present at birth, proliferated
during the first year of life, and then involuted over the ensuing
years. The term "vascular malformations" was reserved
for lesions that were always present (although not necessarily
apparent) at birth, never proliferated, and never involuted.

Hemangiomas

Most hemangiomas first appear soon after birth, but as many as
30% may be apparent at birth [1]. They characteristically proliferate
during the first year of life and then involute sometime during
childhood.

Proliferative Phases

Although the rate and timing of proliferation within this period
is extremely variable, two periods of rapid growth are frequently
seen. The first and most common of these proliferative phases
takes place during the neonatal period and early infancy and the
second, between 4 and 6 months of age. Histologic features of
proliferation include tubules of plump, proliferating endothelial
cells with frequent mitoses and an abundance of mast cells. Little
or no intervascular stroma is apparent, and the lesion appears
cellular (Figure 1).

Hemangiomas may originate in the superficial papillary and/or
reticular dermis. These lesions were previously known as capillary
hemangiomas, but have been renamed cutaneous hemangiomas (Figure
2
). Lesions that arise from deeper subcutaneous tissues, previously
known as a cavernous hemangiomas, are now termed subcutaneous
hemangiomas (Figure 3). Hemangiomas that stem from either the
superficial or deeper tissues but extend across both planes are
referred to as compound hemangiomas [2].

Involution Phase

Proliferation invariably slows by the end of the first year of
life, and a long period of involution follows. During involution,
the once active proliferating endothelial cells become less active
and progressively flatten until late in involution, when they
are not dissimilar from cells seen in normal vascular channels
(Figure 4). The involution process is usually accompanied by an
increase in intervascular fibro-fatty tissue, which eventually
replaces most of the hemangioma. Thus, the lesion changes from
a predominantly cellular to a predominantly vascular tumor and
finally to a fibro-fatty mass of tissue with a few ectatic vascular
channels.

Rate and Patterns of Involution--The rate of involution
is extremely variable. To date, no known characteristics appear
to influence either the rate or completeness of involution.3 Waner
and Suen have identified two distinct patterns of involution (Figure
5
). In the first group, lesions involute rapidly, and the involution
process is complete by between 5 and 6 years of age. This group
is more likely to have a satisfactory outcome and are thus less
likely to require corrective surgery. Finn et al reported that
only 40% of such patients required corrective surgery [3].

In the second group, lesions involute at an extremely slow rate;
this may take up to 12 years and is less likely to be complete.
Approximately 80% of patients with this type of lesion ultimately
require corrective surgery.

Diagnosis

The diagnosis of a hemangioma is made, for the most part, on clinical
grounds. The classic feature, namely, proliferation during the
first year of life, sets this lesion apart from all other vascular
lesions. A superficial or cutaneous lesion is a red, bosselated
mass, whereas a deeper lesion presents as a bluish mass. The mass
is much firmer during proliferation and softer and more easily
compressible during involution. Parents often notice the mass
expanding when the child cries or the lesion is in a dependent
position.

Subcutaneous hemangiomas are often more difficult to diagnose.
When the diagnosis is in doubt, an MRI is useful in confirming
the presence of a hemangioma. Hemangiomas are high-flow,
solid-tissue lesions of intermediate intensity on T1-weighted
presaturation images.

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