eMedicine Specialties > Dermatology > Diseases of the Vessels

Capillary Malformation

Author: Richard J Antaya, MD, Director of Pediatric Dermatology, Associate Professor, Departments of Dermatology and Pediatrics, Yale University
Contributor Information and Disclosures

Updated: Mar 19, 2007

Introduction

Background

Capillary malformation (CM), usually referred to as a port-wine stain or nevus flammeus, is the most common type of vascular malformation. As a congenital malformation of the superficial dermal blood vessels, CM is present at birth and grows in size commensurate with the child; it remains present for life and has no tendency toward involution.

Past nosology of this lesion has resulted in much confusion, and an excessive number of descriptive terms have been applied to it. Confusion originated from difficulty in differentiating vascular malformations from vascular proliferative lesions, such as hemangiomas, and from the use of wholly clinical descriptions in categorizing these lesions. Vascular malformations are categorized by predominate vessel type, such as arterial, venous, lymphatic, capillary, or complex (a combination of different vessels). Although some CMs may be associated with other vessel malformations, most occur alone as venulocapillary malformations.

Pathophysiology

CM and other vascular malformations are the result of abnormal morphogenesis. CMs are characterized by ectatic papillary dermal capillaries and postcapillary venules in the upper reticular dermis, with some evidence of increased vessel density and no apparent proliferation of vessels. These ectatic vessels are lined by flat, benign-appearing endothelial cells, similar to the vessels of normal skin, with similar staining characteristics for endothelial antigens, including fibronectin, von Willebrand factor, and collagenous basement membrane proteins. The endothelial cells also exhibit cell turnover similar to normal vessels, supported by a paucity of mitoses or an uptake of tritiated thymidine. One study demonstrated a mean vessel depth of 0.46 mm in CMs, suggesting that most of the vessels are superficial.

Mounting evidence supports a neural role in both the development and progression of CMs. Animal studies show that the sympathetic nervous system influences the composition and functional properties of the vessel wall during development. Immunohistochemical studies of CMs reveal a significantly decreased density of perivascular nervous tissue in lesional skin, suggesting that inadequate innervation may be responsible for decreased vascular tone and progressive vascular dilatation.

Transcutaneous videomicroscopy reveals 2 distinct patterns of vascular ectasia in CMs. The type 1 abnormality is composed of superficial, tortuous, dilated end capillary loops in the superficial papillary dermis. The type 2 abnormality consists of dilated, ectatic vessels in the superficial horizontal vascular plexus. Some patients exhibit a combination of both abnormal patterns. Evidence suggests that the type 1 abnormality has a better response to 585-nm flashlamp-pumped pulsed dye laser (PDL) therapy than the type 2 abnormality. Moreover, one study found a correlation between the depth and pattern of the CMs and the location of the lesions, demonstrating improved responses to laser therapy with locations demonstrating a type 1 pattern (V3 region of the face, neck, and trunk).

An inactivating mutation of RASA1 on 5q has been detected in some kindreds with multiple, small, round-to-oval, pink CMs (Boon, 2005). These kindreds all had members who also had arteriovenous (AV) malformations or AV fistulae.

Frequency

United States

CM occurs in 0.3-0.5% of newborns.

International

Worldwide, CM occurs in 0.1-2% of newborns.

Mortality/Morbidity

• Isolated CMs do not appear to cause an increase in mortality; however, psychosocial disability secondary to facial disfigurement can be overwhelming. Several studies demonstrate that patients with facial CMs exhibit greater self-concern, ruminative self-doubt in interpersonal interactions, social inhibition, isolated and passive orientation in interpersonal relationships, stigmatization from society, and limitations of privileges and opportunities otherwise afforded to those without facial disfigurement.
• Any morbidity involved with CMs is associated with more extensive vascular malformations.

Race

According to Pratt's study, CM is more common in whites than in African Americans.

Sex

The sex distribution is equal.

Age

CMs are present at birth. Some lesions may not be readily observed at birth because of anemia or plethora. In certain lesions, some lightening of the lesions may occur during the first year of life; however, beyond that time, further lightening is generally not observed.

Clinical

History

Nearly all cases of CM can be diagnosed by taking a careful history and performing a physical examination.

• Onset: CMs are always present at birth, but they may not be apparent early in life because of neonatal anemia or plethora.
• Location
  • Of CMs, most involve the head and the neck.
  • Of facial CMs, 45% are more or less restricted to 1 of the 3 areas supplied by the divisions of the fifth cranial nerve.
  • Of facial CMs, 55% involve an area innervated by more than 1 division of the fifth cranial nerve, crossing the midline or occurring bilaterally.
• Growth
  • Growth in size is commensurate with that of the child.
  • CMs remain present for life.
  • They show no tendency toward involution.
• Evolution
  • CMs may change from pink in infancy to red in early adulthood to deep purple during middle age in some individuals.
  • The surface may become thickened with a cobblestonelike contour. Studies estimate that up to 65% of facial CMs develop these changes during adulthood.
  • Nodular vascular lesions may develop, usually in adulthood.
  • Pyogenic granulomas with bleeding may develop in CMs, even in childhood.
• CM may coexist with other vascular malformations. Geographic (ie, well-circumscribed, sharply bordered) cutaneous lesions carry a much higher probability of associated lymphatic malformations than blotchy stains, especially in patients with Klippel-Trenaunay syndrome.
  

Physical

Early in life, the lesions appear as flat (macular), mostly well-circumscribed patches. The color varies from pink to red to purple. The color of the CM does not correlate with the capillary depth or diameter. Blanching with external pressure is variable. In infancy and childhood, the color darkens with crying, fever, or overheating. CMs are usually unilateral with fairly sharp midline cutoffs. The face is the most frequently affected site, followed by the upper part of the trunk.

Later in life, as the vasculature dilates the CM may evolve into a raised, thickened plaque. The CM becomes deep-red to purple. Lesions may become studded with vascular papules, imparting a cobblestonelike appearance. Vascular papules often form and may be prone to bleeding. Skin and underlying soft tissue or bony hypertrophy may be present. Lobulated capillary hemangiomas (pyogenic granulomas) may form, especially with intraoral lesions.

Associated findings are as follows:

• Glaucoma occurs in approximately 10% of patients with facial CMs, and no leptomeningeal involvement is present. Glaucoma affects 27-45% of patients when CMs involve the skin supplied by both the ophthalmic (CN V1) and the maxillary (CN V2) divisions of the fifth cranial nerve, the trigeminal nerve. Glaucoma is less frequent when the face is involved in only 1 of these upper divisions of the trigeminal nerve or if it is affected solely below the eye; however, the prevalence of eyelid involvement is increased. The prevalence may not be correlated with increased vascularity of the choroid or the bulbar conjunctiva. Glaucoma may be due to increased episcleral venous pressure with resultant elevated intraocular pressure, and it can occur without leptomeningeal involvement (eg, in the absence of Sturge-Weber syndrome).
• Other types of vascular malformations (venous, lymphatic, arterial, or mixed) may be present.
  • Sturge-Weber syndrome
    • Sturge-Weber syndrome (encephalofacial or encephalotrigeminal angiomatosis) is characterized by the triad of CMs involving the upper facial dermis, the ipsilateral leptomeninges, and the ipsilateral cerebral cortex. Some authorities believe that only 2 features are necessary to make this diagnosis. The facial skin supplied by the ophthalmic branch (CN V1) of the trigeminal nerve must be involved with the CM for a patient to meet one of the criteria for Sturge-Weber syndrome.
    • Sturge-Weber syndrome occurs in less than 10% of patients with CMs on the upper eyelid or the forehead. Involvement of areas on the face supplied by only CN V2 or CN V3 does not carry an increased risk for Sturge-Weber syndrome.
    • Typically, CM associated with Sturge-Weber syndrome is more extensive than isolated CM, and it often has bilateral facial involvement. Complications include glaucoma, seizures, hemiplegia, mental retardation, cerebral calcifications, subdural hemorrhage, and an increased prevalence of underlying soft tissue hypertrophy. Large variability exists in the severity of associated symptoms.
  • Klippel-Trenaunay syndrome (angio-osteohypertrophy syndrome) manifests as a triad of CM, congenital varicose veins, and hypertrophy of underlying tissues, particularly skeletal overgrowth. The sex distribution is equal. The lower limbs are involved in 95% of patients, and involvement is unilateral in 85%. Most are asymptomatic at birth, but may experience problems later in childhood. Complications include varicose veins with venous thrombosis and pulmonary embolism; bleeding from varices, the rectum, or the bladder; skin ulceration; increased sweating overlying the CM; leg circumference or length discrepancy with resultant scoliosis; edema; and recurrent infections.
  • With Parkes-Weber syndrome, the diagnostic criteria include an AV malformation in addition to those listed above for Klippel-Trenaunay syndrome. AV fistulae are usually diffuse and difficult to ablate. Almost all patients present in childhood with an enlarged, warm extremity. The prognosis is worse than that associated with Klippel-Trenaunay syndrome. A positive bradycardic reaction (Nicoladoni-Branham sign) portends a poorer prognosis. This test is performed by occluding the arterial inflow by compression with a blood pressure cuff. In a limb with a hemodynamically significant AV malformation, this maneuver leads to reflex bradycardia secondary to a sharp rise in blood pressure. Complications include ulceration and severe lymphedema.
  • In Cobb syndrome (cutaneomeningospinal angiomatosis), a cutaneous vascular lesion in the skin overlying the spine is associated with vascular malformations (venous or AV) in the subjacent spinal meninges. Possible complications result from neurologic damage caused by mass effect on the spinal cord or nerves, bone erosion, and subarachnoid hemorrhage.
  • Wyburn-Mason syndrome (unilateral retinocephalic syndrome), also known as Bonnet-Dechaume-Blanc syndrome, manifests as facial CMs associated with unilateral AV malformation of the retina and the intracranial optic pathway. Physical findings include monocular amblyopia, mild proptosis, and dilatation of conjunctival vessels. CMs may occur anywhere on the ipsilateral face (not just the eyelids or periorbitally), and they may have associated facial hypertrophy or occasional involvement of the optic chiasm, the hypothalamus, the midbrain, and the basal ganglia, with associated mental retardation or neurologic signs and symptoms.
  • Nevus vascularis mixtus is the name given when a CM is paired with nevus anemicus, an example of didymosis or twin spotting.
• CM overlying the lumbar spine may be a marker for an underlying primary skeletal or neurologic anomaly, such as spinal dysraphism, tethered spinal cord, lipomeningocele, or diastematomyelia. The prevalence of underlying defects is increased when multiple abnormalities are present in the lumbar skin. Skin markers include acrochordons (skin tags), an abnormal tuft of hair (fawn's tail), lipomas, an irregular (usually deviated) gluteal cleft, or a dermal sinus tract or sacral dimple that is large or superior to the gluteal fold. Guggisberg et al found that none of 16 patients with an isolated CM showed occult spinal dysraphism (OSD), whereas 7 of 10 patients with CMs in combination with other lumbar congenital anomalies did have an OSD. Conversely, Tubbs et al found that 21 (17.5%) of 120 patients with an isolated CM harbored an OSD, and they recommended MRI for all patients who present with an isolated lumbar CM.
• Phakomatosis pigmentovascularis refers to the presence of a CM with a melanocytic or other type of nevus.
  • This phenotype is another example of twin spotting, with the pathogenesis hypothesized to include developmental abnormalities, perhaps paired mutations of varied neural crest–derived elements, such as vasomotor nerves and melanocytes.
  • The histopathologic findings of a CM in phakomatosis pigmentovascularis are the same as those for isolated CMs.
  • Four classification types are described. Type I is composed of CM and nevus pigmentosus et verrucosus or epidermal nevus. Type II is a CM and dermal melanocytosis with or without nevus anemicus; this is the most common type. It also includes nevus of Ota (oculocutaneous melanosis) and can be associated with Sturge-Weber syndrome and Klippel-Trenaunay syndrome. Type III is a CM and nevus spilus with or without nevus anemicus. Type IV is a CM, nevus spilus, and dermal melanocytosis with or without nevus anemicus. Subdivisions of each type include subtype a for cutaneous involvement only and subtype b for cutaneous and systemic involvement. No systemic involvement is reported for type I.
  • Recently, another classification scheme has been proposed by Happle. This includes 3 different distinct categories based on the type of associated lesion: phacomatosis cesioflammea (CM with bluish gray spots as observed with various lesions of dermal melanocytosis), phacomatosis spilorosea (pale pink telangiectatic CM associated with a nevus spilus), and phacomatosis cesiomarmorata (cutis marmorata telangiectatica congenita with blue spots). A final category includes others that cannot be included in one of the other 3 variants.

Causes

The exact mechanism remains unknown.

• Evidence for genetic influence is lacking. Postzygotic somatic mutations may account for the mosaic and twin-spotting phenotypes.
• CMs may result from a neural deficiency of sympathetic innervation of the superficial dermal blood vessels.

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