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Paediatric Surgery, Shaikh Zayed Hospital, Lahore
Vascular Tumors - Hemangiomas
Table of Contents
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Introduction
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Diagnosis
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Screening of relevant systems
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Kassabach–Merritt phenomenon
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Treatment
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Rapid Points
Introduction
Hemangiomas usually present as a sold, relatively fixed mass with some overlying vascular markings in the overlying and adjacent skin. DDs in the cervical region can be a cervical teratoma, a cervical neuroblastoma, or a large cystic lesion complicated by hemorrhage.
A hemangioma is a true neoplasm with a proliferative phase, whereas a vascular malformation is an anomaly of the arterial, venous, or lymphatic system (or combination) that has no neoplastic features.
Hemangiomas are considered benign vascular tumors and are now classified in six categories:
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Infantile,
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congenital,
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tufted,
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spindle-cell,
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epithelioid, and
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pyogenic granuloma
Infantile Hemangioma
The infantile hemangioma is by far the most common. Risk factors for the occurrence of an infantile hemangioma include female sex, Caucasian race, prematurity, low birth weight, multiple gestations, and advanced maternal age. The lesion typically progresses through three phases: proliferative, involuting, and involuted. The median age of appearance of an infantile hemangioma is 2 weeks, and the great majority appears before 3 months of age. The proliferative phase lasts several months but usually ends before the patient’ s first birthday. It is characterized histologically by proliferation of benign endothelial-like cells that possess specific histochemical markers.
Interestingly, many of these markers are also found in the placenta, giving some support to the theory that embolization of placental cells may be the source of an infantile hemangioma. Angiogenic peptides, such as vascular endothelial growth factor (VEGF) and basic fibroblast growth factor appear to drive the proliferative phase. The involution period is quite variable. It can occur over a few months or several years. In the involuted phase, the hemangioma may completely disappear or may leave a residual fibrofatty mass in the soft tissues, or skin telangiectasia, or both.
Approximately 80% of infantile hemangiomas are cutaneous with a predilection for the head and neck. However, it is important to remember that a head and neck soft tissue lesion may represent the tip of the iceberg with a much larger extension into the deep tissues and vessels
Congenital Hemangiomas
Congenital hemangiomas are further classified by their behavior as rapidly involuting (RICH), noninvoluting (NICH), or partially involuting (PICH). These lesions are increasingly being diagnosed on prenatal ultrasound and fetal MRI.
Diagnosis
Initial Diagnosis:
An ultrasound with Doppler interrogation is the best initial test. It will differentiate a cystic from a solid lesion, demonstrate calcifications that may be associated with teratoma or neuroblastoma, and show vascular flow patterns that may point to a vascular tumor or malformation.
Best Diagnostic Modality:
MRI is the best cross-sectional imaging study and can differentiate
hemangioma from lymphatic, venous, and arteriovenous malformations by
combining the findings of T1-weighted images, T2-weighted images,
contrast enhancement, and flow gradient.
The characteristic findings of hemangiomas are a soft tissue mass that is isointense or hypointense on T1, hyperintense on T2 with flow voids, has uniform contrast enhancement, and shows high-flow levels within and around the soft tissue mass.
A biopsy in this situation may lead to severe hemorrhagic complications. It is therefore not indicated.
Screening of Relevant Systems
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Multiple cutaneous hemangiomas may be associated with hemangiomas in deep organs, particularly the liver. A screening ultrasound of the liver should therefore be conducted in all patients with five or more cutaneous lesions.
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Multiple hemangiomas may also produce consumptive hypothyroidism due to excessive iodothyronine deiodinase expression. TSH level should be checked in these patients.
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Hemangiomas in the lumbosacral areas warrant imaging of the spinal cord and vertebral column to rule out spinal dysraphism abnormalities. Perineal hemangiomas can be associated with urogenital and anorectal anomalies. Both perineal and lumbosacral hemangiomas are at high risk of ulceration.
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One of the most common associations with hemangioma is the PHACE syndrome, consisting of posterior fossa brain abnormalities, facial hemangioma, arterial malformations, coarctation of the aorta and other cardiac defects, and eye abnormalities. Patients with facial hemangiomas larger than 5 cm should be screened for this syndrome by undergoing MRI, magnetic resonance angiography, echocardiography, and eye examination.
Kassabach–Merritt phenomenon
Introduction:
Severe thrombocytopenia, known as the Kassabach–Merritt phenomenon is actually rarely seen with hemangiomas. The onset of this phenomenon, associated with a vascular lesion, should raise the suspicion for a kaposiform hemangioendothelioma (KHE). This is a rare vascular tumor of childhood, presenting at a mean age of 4 years. It has a predilection for the trunk, but can also occur in the liver, head and neck, or extremities.
The tumor is classified as a locally aggressive or borderline vascular tumor. Unlike infantile hemangioma, KHE does not regress spontaneously
Diagnosis:
A biopsy is required to establish the diagnosis.
Treatment:
Vincristine chemotherapy has traditionally been used, with the aim of shrinking the lesion prior to attempting a resection. However, complete resection is not often possible. More recently, the mTOR inhibitor, sirolimus, has been shown to be highly effective. In addition, it is administered by the oral route, is usually well tolerated, and has a favorable toxicity profile. Many vascular anomaly centers now use sirolimus as first-line therapy for KHE for prolonged periods of months to years.
Treatment
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Systemic steroids were, until recently, considered first-line therapy for symptomatic hemangiomas. However, propranolol has now emerged as the first drug of choice. The drug does have potential serious side effects, particularly hypotension and hypoglycemia. However, established protocols have now emerged for its initiation and continuation.
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Topical application of timolol maleate has shown high success rates in the treatment of localized, superficial hemangiomas.
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Other agents, such as intralesional steroids, vincristine, and interferon are now rarely used. Interferon in particular has been abandoned due the risk of spastic diplegia. Pulsed-dye laser use has been reported, but appears to be most effective for the treatment of residual telangiectasia after involution of a hemangioma
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Selective embolization has been successfully used for large symptomatic hepatic lesions
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Resection may be effective for pedunculated lesions or other superficial symptomatic hemangiomas.
Rapid points
