Gastrointestinal Vascular Anomalies

Vascular (or vasoproliferative) neoplasms

Vascular malformations

Infantile hemangioma

Slow-flow vascular malformations

Congenital hemangiomas

(Rapidy involuting congenital hemangioma (RICH)

Non-involuting congenital hemangioma (NICH)

Capillary malformation

Venous malformation

Lymphatic malformation

Kaposiform hemangioendothelioma and tufted angiomas (with or without Kasabach–Merritt syndrome)

Fast-flow vascular malformations

Spindle cell hemangioendothelioma

Arterial malformation

Epithelioid hemangioendothelioma

Arteriovenous malformation

Other rare hemangioendotheliomas (i.e., composite, retiform, and others)

Arteriovenous fistula

Angiosarcoma

Combined vascular malformations (various combinations of the above)

Dermatologic acquired vascular tumors (i.e., pyogenic granuloma)

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Classification into either of these groups is determined by clinical appearance, by radiological and pathological features, and by biological behavior. In rare cases, vascular tumors and vascular malformations can coexist [6].

In order to understand different modalities of investigation and treatment, it is important to appreciate the different origin and behavior of vascular anomalies irrespective of their site. We describe the lesions with special emphasis on gastrointestinal (GI) lesions.

Group I: Vascular Tumors

Congenital vascular tumors can be divided into the following major groups:

Infantile hemangiomas
Congenital hemangiomas
Kaposiform hemagioendotheliomas
Other rare tumors (tufted angiomas, angiosarcomas)

Hemangioma is the most common tumor of infancy and childhood with recorded 1.0–2.6 % incidence among Caucasian neonates. By the age of 1 year, some 4–12 % of Caucasian children have a hemangioma. The female-to-male ratio is 3:1. Hemangiomas are more common in premature babies [7].

Infantile Hemangiomas

Infantile hemangiomas are proliferating endothelial tumors. They are strongly characterized by endothelial expression of glucose transporter protein-1 (GLU-1). GLU-1 is not observed in other vascular malformations and vascular tumors, except for some focal areas in cases of RICH [7]. Infantile hemangiomas, usually apparent in the early neonatal period, proliferate until 1 year of age then slowly regress until the age of 7, when they end in the involution phase .

Congenital Hemangiomas

Congenital hemangiomas are fully formed at birth and can follow two patterns of biological behavior: either rapidly involuting congenital hemangiomas (RICH) or non-involuting congenital hemangiomas (NICH). They often have a large feeding vessel and sometimes can cause shunting and cardiac overload .

Kaposiform Endotheliomas

Kaposiform endotheliomas and tufted angiomas can result in Kasabach–Merritt-type coagulopathy, characteristic of which is platelet trapping by abnormal endothelium and the consumption of fibrinogen. Thrombocytopenia can be life-threatening, especially when resulting in disseminated intravascular coagulation. The Kasabach–Merritt phenomenon is associated with a mortality rate of 14–24 % [8, 9].

If patients present with five or more cutaneous hemangiomas, the abdominal ultrasound scan is indicated looking for visceral lesions, more commonly situated in the liver.

The hemangiomas of the GI tract are rare and only account for approximately 0.3 % of all GI tumors. They have a tendency towards multiplicity (intestinal hemangiomatosis) and solitary tumors are uncommon. Patients may present with GI hemorrhage, anemia, or symptoms of obstruction. Interestingly, 11–30 % of GI hemangiomas may remain asymptomatic [10, 11].

Group II: Vascular Malformations

Vascular malformations are localized defects of vascular development, which occur in the process of vascular morphogenesis.

Although most vascular lesions are sporadic, inheritance has been observed and has thus provided a route to genetic analysis. Sporadic forms usually present as single lesions, but multiple lesions have been observed in familial cases.

Ninety percent of vascular malformations are present at birth. Estimated incidence of vascular anomalies in the general population is approximately 1.5 % [12].

Female-to-male ratio is 1:1. These malformations infiltrate the surrounding tissue, never regress and can worsen over time if not treated. Changes in hemodynamic factors such as arteriovenous shunting or venous stasis can accelerate growth and morbidity.

The “vascular malformations” group can also be subdivided into fast flow (arterial or arteriovenous) and slow flow (capillary, lymphatic, or venous). If fast-flow lesions are localized subcutaneously, they may become more erythematous, and may develop a palpable thrill and a bruit.

Vascular malformations of the GI tract are rare in children but they can be diagnosed at any age, including newborns [13]. They may appear anywhere in the GI tract from mouth to anus and may coexist with similar lesions on the skin.

Patients may present with recurrent abdominal pain , GI bleeding, acute or, more often, chronic anemia, intestinal obstruction, volvulus, intussusception, and palpable mass lesion. Sometimes, because of mucosal edema, nodularity, and vascular congestion, these lesions might be mistaken for inflammatory bowel disease. Bleeding per rectum may also be misleading towards the diagnosis of symptomatic Meckel’s diverticulum. Intestinal lesions often represent a diagnostic challenge requiring sophisticated methods of investigation.

Group II: Vascular Malformations: Associated Syndromes

Certain syndromes are associated with GI vascular malformations, including:

1. Osler–Weber–Rendu disease (hereditary hemorrhagic telangiectasia)
2. Klippel–Trenaunay syndrome
3. Blue rubber bleb nevus (BRNB) syndrome

Osler–Weber–Rendu Disease (Hereditary Hemorrhagic Telangiectasia)

This is a genetic disorder inherited in autosomal dominant manner occurring in 1:5000 of the general population. Genetic diagnosis is difficult but tests are available for the ENG, ACVRL1, and MADH4 mutations [14].

The condition typically presents with distinctive small skin and mucosal vascular malformations (telengiectasias), and may appear in the nose, lips, fingers, and along the GI tract. Larger arteriovenous malformations are usually localized in the lungs, liver, brain and, occasionally, the spine. Though the main clinical problem is usually epistaxis, GI bleeding may also occur, but it is rare in pediatric population. The malformations developing in the liver may eventually lead to portal hypertension , high-output cardiac failure, or encephalopathy. The clinical diagnosis is based on the Curaçao criteria [15], which are:

Spontaneous recurrent epistaxis
Multiple telangiectasia in typical locations
Proven visceral arteriovenous malformations (lung, liver, brain, spine)
First-degree family member with hereditary hemorrhagic telangiectasia

Treatment of anemia due to GI bleeding is mainly symptomatic but in severe cases argon plasma coagulation or laser therapy may be applied.

Klippel–Trenaunay Syndrome

This is a relatively rare condition with approximate incidence of 1:30,000 live births [16]. Historically, it is characterized by a triad of symptoms: capillary skin malformation (port wine stain), varicose veins (especially persistent embryonic lateral vein of Servelle), and bony/soft tissue hypertrophy of the extremity. This hypertrophy is caused by venous and lymphatic malformations localized in the soft tissue but often involving the bony structures. Most commonly, one extremity is affected, usually the leg, but multiple involvement is also possible.

The etiology of the syndrome is not entirely clear but it is believed that most cases happen due to sporadic gene mutation, though some autosomal dominant inheritance cases are also reported. Mutations in PI3K-AKT gene pathway may play a role in development of the condition [17].

In association with the classical triad of clinical symptoms, the GI tract may also be affected by vascular malformations. Though intestinal involvement is rare (1–12 % of all patients affected by the syndrome)—the risk of bleeding should always be considered [18].

BRNB Syndrome (Bean Syndrome)

This syndrome is characterized by cutaneous and visceral venous malformations. These malformations can occur in any tissue but are most prominent in the skin and in the GI tract, the small bowel being the most frequently affected part. Their number can range between several to hundreds, such as the 557 in one patient reported by Fishman in 2005 [19]. Cutaneous lesions are generally small (about 1–2 cm or even smaller), rubbery, compressible, blue to purple nipple-like nodules often found on the face, the upper limbs, and the soles of the feet.

Most cases are sporadic, but some autosomal dominant transmission has also been reported.

A common problem is GI bleeding presenting at early age and continuing throughout life, resulting in chronic anemia requiring repeated blood transfusions. A broad spectrum of treatment options is available, from conservative and endoscopic treatment to an aggressive surgical approach.

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