Lymphangioma are malformations of the lymphatic system characterized by lesions that are thin-walled cysts. These malformations can occur at any age and may involve any part of the body, but 90% occur in children less than 2 years of age and involve the head and neck.Lymphangiomas are commonly diagnosed before birth using fetal ultrasonography. Acquired lymphangiomas may result from trauma, inflammation, or lymphatic obstruction. Since they have no chance of becoming malignant, lymphangiomas are usually treated for cosmetic reasons only.

References Recent Progress in Lymphangioma 34976885 
Lymphangioma (lymphatic malformation, LM), a congenital vascular disease, is a low-flow vascular abnormality in lymphatic diseases that is characterized by excessive growth of lymphatic tissue during prenatal and postpartum development. The incidence rate of LM is ~1:2000–4000, with no variation between genders and races. Most patients (80–90%) are diagnosed before the age of two. The clinical manifestations of lymphangioma are quite different among patients, varying from local swelling leading to superficial mass to a large area of diffuse infiltrating lymphatic channel abnormalities resulting in elephantiasis. Cervicofacial LM can cause facial elephantiasis, and in some severe cases, it can lead to serious disfigurement of the face. Tongue LM can lead to mandibular overgrowth and occlusal asymmetry, and oral and cervical LM can cause obstructive acute respiratory distress and life-threatening situations. Orbital LM may lead to decreased vision, decreased extraocular muscle movement, ptosis and exophthalmos. LM of the extremities can trigger swelling or gigantism, accompanied by overgrowth of soft tissue and bones. LM usually grows slowly and steadily, but under certain conditions, such as infection, hormonal changes or trauma, it can grow explosively and become a life-threatening disease requiring immediate treatment.
 Lymphangioma: Is intralesional bleomycin sclerotherapy effective? 22279495 
This is a retrospective study of 24 children diagnosed with lymphangioma and treated with intralesional injection of bleomycin aqueous solution from January 1999 to December 2004. Complete resolution was seen in 63% (15/24) of lesions, 21% (5/24) had good response and 16% (4/24) had poor response. The tumour recurred in 2 patients. Two other patients had abscess formation at the site of injection. No other serious complications or side effects were observed.
 Surgical Resection of Acquired Vulvar Lymphangioma Circumscriptum - Case reports 24665431 
The predominant types of lymphangioma are lymphangioma circumscriptum (LC), cavernous lymphangioma, cystic hygroma, and lymphangioendothelioma. These entities account for approximately 26% of benign vascular tumors in children but are rarer in adults. LC is the most common form of cutaneous lymphangioma and is characterized by superficial lymphatic ducts protruding through the epidermis. This condition results in clusters of clear fluid-filled vesicles resembling frog spawn and associated tissue edema. It is usually found on the proximal extremity, trunk, and axilla, which has an abundant lymphatic system. A 71-year-old female presented to our outpatient clinic with persistent edema of both lower limbs, clusters of pink labial papules, pruritus, and watery lymph oozing. We removed all the papules by performing bilateral major labiectomy down to the level of Colles' fascia, sparing the clitoris and fourchette.