risks from surgical removal, can also be treated with sclerosing agents, systemic medication, or through observation. Sirolimus Sirolimus is used to treat lymphangioma . Treatment with sirolimus can decrease pain and the fullness of venous malformations, improve coagulation levels, and slow the growth of abnormal lymphatic vessels. Sirolimus is a relatively new medical therapy for the treatment of vascular malformations, in recent years, sirolimus has emerged as a new medical treatment option for both vascular tumors and vascular malformations, as a mammalian target of rapamycin (mTOR), capable of integrating signals from the PI3K/AKT pathway to coordinate proper cell growth and proliferation. Sirolimus (rapamycin, trade name Rapamune) is a macrolide compound. It has immunosuppressant and antiproliferative functions in humans. 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 Lymphatic vessel diseases Vascular neoplasia