Hemangiomas are common benign tumors of infancy. They usually first appear after birth and grow gradually within the first year and disappear thereafter.
Hemangiomas are common in the head and neck, although they can be seen in any part of the body. Although most lesions are easily noticeable (strawberry-like appearance), deeper hemangiomas may be covered by normal skin or show minimal skin discoloration. As the hemangioma shrinks, the color of the lesion fades and the lesion itself feels softer. Most hemangiomas can be recognized easily, and require no imaging studies for diagnosis, although deeper hemangiomas may require imaging studies (typically MRI) for diagnosis and to evaluate the extent of the lesion. Additional imaging studies (MRI of the head and/or chest) may also be required for extensive cervicofacial hemangiomas to rule out intracranial and intrathoracic abnormalities. If the diagnosis of hemangioma is unclear based on its clinical presentation and/or imaging findings, a biopsy may be required to rule out malignancies.
Congenital Hemangioma (RICH)
This is a rare form of hemangioma that differs by its presentation at birth and rapid shrinkage, usually within a year after birth. The imaging findings can be confused with other vascular anomalies, typically arteriovenous malformation (AVM). Platelet counts should be monitored closely to rule out consumptive coagulopathy.
Non-involuting Hemangioma & Intramuscular hemangioma
These rare tumors are seen beyond infancy and show similar imaging findings to more commonly seen hemangiomas. A little is known regarding the etiology, as well as possible treatment options.
Kaposiform Hemangioendothelioma (KHE)
This is a vascular tumor associated with the Kasabach-Merritt phenomenon (severe coagulopathy due to platelet trapping and spontaneous bleeding). An ill-defined purpuric mass is a common presentation. Destructive bone changes in adjacent bones are common. Patients with KHE need to be closely monitored for severe coagulopathy.
Fast-Flow Vascular Malformations
Arteriovenous Malformation (AVM): This vascular malformation is characterized by abnormal vascular channels ("nidus") that connects the arteries and veins. Although AVMs are present at birth, they often become prominent later in life (usually during puberty). Trauma or pregnancy can also trigger this rapid enlargement. Patients usually present with pain, a pulsatile mass, skin redness, enlargement of the diseased body part, bleeding and/or heart failure. The overlying skin may be completely normal. Imaging is usually indicated to confirm the diagnosis and to evaluate the extent of the malformation. MRI is the preferred imaging modality, although ultrasound examinations can be used to evaluate the flow pattern of the malformation. Conventional angiography may be required for the diagnosis of AVM, although it is usually reserved for endovascular intervention (embolization).
Arteriovenous Fistula (AVF)
This is a relatively benign malformation that shows a single abnormal vascular communication between an artery and a vein. AVF may be congenital or is acquired as a result of trauma. AVFs may be recognized by a pulsatile mass or bruit and may cause heart failure. Most AVFs are curable by endovascular intervention (embolization) or surgical ligation.
Slow-Flow Vascular Malformations
Capillary Malformation (CM) (port-wine stain): CMs are common birthmarks and are generally recognized clinically. Imaging is unnecessary in most patients. CMs can present as small, localized lesions or they can be quite extensive. A CM can be a clue to significant underlying structural abnormalities such as encephalocele, spinal dysraphism, or Sturge-Weber syndrome. Although imaging (typically MRI) is not necessary to make the diagnosis of CM, it may be indicated to rule out underlying structural abnormalities.
Venous Malformation (VM)
VM is probably a more common anomaly than previously thought. A common error in diagnosis or misconception is the misclassification of venous malformations as hemangioma or cavernous hemangioma, which has caused significant confusion within the medical community and among patients and their families, and has even been the cause of inappropriate treatment in some cases. Most VMs are single isolated malformations, although some may be seen as part of a syndrome such as Klippel-Trenaunay syndrome (KTS), Maffucci syndrome, or blue rubber bleb nevus syndrome (BRBNS). A VM is characteristically soft and easily compressible. Most VMs are associated with bluish skin discoloration. Increasing swelling with dependency is common. Imaging is usually needed to confirm the diagnosis and to evaluate the extent of the lesion. MRI is the preferred imaging modality. Most patients seek treatment because of pain and discomfort and/or the appearance of the involved body part. Treatment is usually determined based on the severity of the complaint, as well as the lesion's size and extent. When the lesion is small, it can be removed surgically. However, most lesions are much larger than initially expected and involve several muscles and/bones, which makes the surgical removal of the lesion infeasible. Sclerotherapy (injection of sclerosant medication into the lesion) offers a good treatment alternative for most patients. Alcohol is the most commonly used sclerosant agent, although two very important complications of sclerotherapy should be of concern: scarring of the skin and nerve damage. It is very important that sclerotherapy is performed with an interventional radiologist who has experience and training with vascular anomalies and interventional techniques in order to treat these malformations and obtain the best possible results with minimal complications.
Glomuvenous malformation (Glomoangioma)
This is a familial disease that is characterized by several skin VMs that are often tender, blue, and nodular.
Lymphatic Malformation (LM)
LMs are not as common as VMs. These malformations range from small localized lesions to very large lesions that may diffusely involve large body parts (e.g., extremity, head and neck). LMs are classified as microcystic, macrocystic, or combined. The term "cystic hygroma", which was commonly used for the macrocystic LM, is no longer used. Most lesions occur in the cervicofacial area (head and neck). The overlying skin can be normal, or it may have tiny vesicles. The orbit is a common location and orbital involvement may endanger the optic nerve due to bleeding into the lesion resulting in rapid enlargement of the malformation. Surgical or interventional decompression may be required to save the optic nerve. LM of the mouth or the neck may cause airway obstruction. LMs are rarely associated with progressive bone destruction (Gorham-Stout Syndrome). On imaging studies (MRI or CT), microcystic LM is usually seen as a solid abnormal tissue without any cystic lesions and may be confused with other solid lesions. LM can be distinguished from VM by its minimal or absent contrast enhancement on MRI imaging.
Combined Vascular Malformations
Klippel-Trenaunay syndrome (KTS): KTS is a slow-flow complex (lymphatic and venous) vascular malformation and is characteristically associated with the overgrowth of the extremity (typically leg). Capillary stains are usually seen in a geographic pattern over the involved body part. In addition to ambulatory difficulties related to an enlarged extremity, the patients may suffer from sepsis, thrombophlebitis and pulmonary embolism. In severe cases, the deep venous system may be totally non-functional and drainage may occur via markedly dilated, anomalous superficial veins. The pathognomonic marginal vein of Servelle is frequently identified. It is important to confirm the adequacy of the deep venous system (by using either MRV or contrast venography) before any surgical intervention.
Proteus syndrome is another rare slow-flow complex vascular anomaly and usually presents with verrucous nevus, lipomas or lipomatosis (fat deposition) macrocephaly, asymmetric limbs with partial gigantism of the hands and feet, and cerebriform plantar thickening. Abundant fat deposition is a characteristic finding on imaging studies.
Parkes-Weber syndrome (PWS)
PWS is a fast-flow complex malformation (similar to AVM) that usually involves an entire extremity and is associated with a stain over the enlarged extremity. Cutaneous warmth, bruit or thrill are common and are the differentiating features from a simple CM.
In this entity, slow-flow vascular anomalies (similar to VM) are associated with bone lesions (bone exostoses and enchondromas). The bone lesions usually appear in childhood, and the vascular lesions manifest later. Malignant bone tumors develop in 20-30% of patients.