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Prevalence is unknown but the lesions appear to be rare.

NICH have long been confused with infantile immature hemangiomas in their involuting stage, however, NICH are now clearly distinguished on the basis of their clinical features, course, pathology and immunophenotype. NICH are generally less expansive at birth than RICH. They are flat or slightly bossed, round or oval, and are usually solitary. The outer area appears white. The centre varies from pinkish with minor telangiectasia, to deep purple with closely packed thin telangiectasia. NICH are mainly located on the head or neck (43% of cases), and limbs (38% of cases). NICH will not regress: they persist indefinitely with proportionate growth as the child becomes older.

The etiology is unknown.

At birth, color Doppler ultrasound reveals a fast-flow lesion and minor arteriovenous fistulas are occasionally detected. However, in some patients, NICH may increase equatorial venous drainage and arteriovenous fistulas may become obvious on examination by color Doppler ultrasound. On MRI, NICH show isointensity on T1-weighted images, hyperintensity on T2-weighted images, and intensive enhancement after intravenous gadolinium administration. However, all of these findings are similar to those seen in infantile hemangiomas (IH). Immunohistochemical studies can be used to differentiate NICH and IH, as in contrast to IH, the endothelial cells of NICH lack immunoreactivity for GLUT-1. Histopathologic studies reveal that NICH consist of rather large lobules made of small capillaries lined by endothelial cells with hobnailed nuclei. Lobules are separated by dense fibrous tissue. Elongated thin-walled vessels and a large distorted channel are present in their center. Extralobular vessels are large. Calcifications may be seen. Numerous alpha-actin-positive cells are observed in the lobules.

For lesions of intermediate size it may be difficult to distinguish between NICH and RICH at birth. NICH must also be differentiated from the congenital, single plaque-type of tufted angioma and from a kaposiform hemangioendothelioma (see these terms), and a biopsy may be indicated.

In contrast to RICH, prenatal color Doppler ultrasound follow-up during pregnancy rarely leads to detection of NICH. NICH are not associated with any specific risks during delivery.

Genetic counseling should not be recommended as this rare tumor is sporadic. NICH never involute.

The only therapeutic option is surgical excision and plastic reconstruction when there is cosmetic impairment. Neither arterial embolization alone, nor pulsed dye laser photocoagulation are of benefit. Performed 24 hours before excision, arterial embolization prevents excess intra-operative bleeding in some large NICH with arteriovenous fistulas detected by Doppler ultrasound.

Prognosis is good: NICH is a benign lesion, only impairing the cosmetic aspect of the skin. No severe complications have been reported.