Cysts occur when large and confluent focuses of PVL, with mixed necrosis (kollikvacia in the center and coagulation rim at the periphery). Around the foci is generally defined area of other lesions of the brain white matter - the death of prooligodendrocytes, proliferation mikrogliocytes and astrocytes, swelling, bleeding, loss of capillaries, and others (the so-called "diffuse component PVL"). However, diffuse lesions without necrosis are not PVL. Presentation
It is often impossible to identify PVL based on the patients physical or behavioral characteristics. The white matter in the periventricular regions is involved heavily in motor control, and so individuals with PVL often exhibit motor problems. However, since healthy newborns (especially premature infants) can perform very few specific motor tasks, early deficits are very difficult to identify. As the individual develops, the areas and extent of problems caused by PVL can begin to be identified; however, these problems are usually found after an initial diagnosis has been made. The extent of signs is strongly dependent on the extent of white matter damage: minor damage leads to only minor deficits or delays, while significant white matter damage can cause severe problems with motor coordination or organ function. Some of the most frequent signs include delayed motor development, vision deficits, apneas, low heart rates, and seizures. Delayed motor development
Delayed motor development of infants affected by PVL has been demonstrated in multiple studies. One of the earliest markers of developmental delays can be seen in the leg movements of affected infants, as early as one month of age.
It inhibits activation of T cells and B cells by reducing their sensitivity to interleukin-2 (IL-2) through mTOR inhibition. Prognosis
The prognosis for lymphangioma circumscriptum and cavernous lymphangioma is generally excellent. This condition is associated with minor bleeding, recurrent cellulitis, and lymph fluid leakage. Two cases of lymphangiosarcoma arising from lymphangioma circumscriptum have been reported; however, in both of the patients, the preexisting lesion was exposed to extensive radiation therapy.In cystic hygroma, large cysts can cause dysphagia, respiratory problems, and serious infection if they involve the neck. Patients with cystic hygroma should receive cytogenetic analysis to determine if they have chromosomal abnormalities, and parents should receive genetic counseling because this condition can recur in subsequent pregnancies.Complications after surgical removal of cystic hygroma include damage to the structures in the neck, infection, and return of the cystic hygroma. Epidemiology
Lymphangiomas are rare, accounting for 4% of all vascular tumors in children. Although lymphangioma can become  evident at any age, 50% are seen at birth, and 90% of lymphangiomas are  evident by 2 years of age. History
In 1828, Redenbacher first described a lymphangioma lesion. In 1843, Wernher gave the first case report of a cystic hygroma, from the Greek "hygro-" meaning fluid and "oma" meaning tumor. In 1965, Bill and Summer proposed that Cystic hygromas and lymphangiomas are variations of a single entity and that its location determines its classification. References
External links

Cystic hygroma at eMedicine