Adolescent with enlarging asymptomatic birthmark


An 11-year-old girl asks her pediatrician about an asymptomatic birthmark on her right thigh that drains clear to slightly bloody-tinged fluid occasionally when scratched. It has increased in size proportionally as she has grown.


An 11-year-old girl asks her pediatrician about an asymptomatic birthmark on her right thigh that drains clear to slightly bloody-tinged fluid occasionally when scratched. It has increased in size proportionally as she has grown.

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Clinical findings

Lymphatic malformations (LMs) are rare, low-flow vascular anomalies of the lymphatic system consisting of localized or diffuse malformations of lymphatic channels.1,2 The clinical presentation of LMs varies depending on the location and extent of the lesions.1 Lymphatic malformations most commonly affect lymphatic-rich areas such as the neck and axilla, but they can involve any part of the body.1,3

Lymphatic malformations may be classified as macrocystic (diameter >1 cm), microcystic (diameter <1 cm), or mixed cystic lesions.1,2 Macrocystic lesions present as large, smooth, translucent masses under normal or bluish skin, while microcystic lesions present as small, clear vesicles that permeate the subcutaneous tissue and muscles.3 Lymphatic malformations generally increase in size proportionally as the patient grows; spontaneous resolution occurs only rarely. Infection, trauma, and intracystic hemorrhage can precipitate sudden, but temporary, enlargement of LMs.1


Although the exact pathogenesis of LMs is unknown, they are thought to result from molecular defects in the development of the lymphatic system during embryonic growth.3In rare cases, LMs can be associated with syndromic disorders including Turner syndrome, Proteus syndrome, Klippel-Trenaunay-Weber syndrome, Milroy disease, and CLOVES (congenital lipomatous overgrowth, vascular malformations, epidermal nevis, spinal/skeletal anomalies/scoliosis) syndrome.1,4


Lymphatic malformations, which affect males and females equally, are estimated to occur in 1 out of 2000 to 4000 live births.1,3 They are usually apparent at birth or by age 2 years, but in rare cases they may not manifest until adolescence or adulthood.2,3


Lymphatic malformations can cause functional impairment of nearby structures and disfigurement of affected areas.3 Spontaneous leakage of lymph and blood from pathologic vessels can lead to recurrent cellulitis, which can cause significant pain, swelling, disfigurement, and even sepsis. Given the potential morbidity, infections require aggressive antimicrobial and anti-inflammatory therapy. Spontaneous bleeding within cysts can cause pain, inflammation, and compression of adjacent organs.

Diagnosis and treatment

Lymphatic malformations may be diagnosed prenatally via routine ultrasound in the late second to third trimesters.1,3 After birth, the diagnosis is based on history and physical examination. Magnetic resonance imaging and computed tomography are sometimes performed to confirm the diagnosis and evaluate the extent of the LM.3 Treatment, which aims to support and optimize patients’ quality of life, often involves coordinated efforts of a multidisciplinary team of specialists.1,5 Treatment varies based on a variety of factors, including the clinical presentation, size of the lesion, anatomic location, and complications.3Current treatment options include observation, surgery, sclerotherapy, laser therapy, and radiofrequency ablation.1,3 Emerging medical and surgical therapies include sildenafil, propranolol, sirolimus, and vascularized lymph node transfer.

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Given the lack of treatment algorithms for LMs and the multiple potential treatment modalities, the treatment plan should be based on the comfort and experience of the treating team and the preferences and goals of the patient’s family.3

Patient outcome

Observation was favored for this patient’s small, asymptomatic lymphatic malformation. She remains free of complications and reports no concerns.



1. Defnet AM, Bagrodia N, Hernandez SL, Gwilliam N, Kandel JJ. Pediatric lymphatic malformations: evolving understanding and therapeutic options. Pediatr Surg Int. 2016;32(5):425-433.

2. Fevurly RD, Fishman SJ. Vascular anomalies in pediatrics. Surg Clin North Am. 2012;92(3):769-800.

3. Elluru RG, Balakrishnan K, Padua HM. Lymphatic malformations: diagnosis and management. Semin Pediatr Surg. 2014;23(4):178-185.

4. Brouillard P, Boon L, Vikkula M. Genetics of lymphatic anomalies. J Clin Invest. 2014;124(3):898-904.

5. Balakrishnan K, Edwards TC, Perkins JA. Functional and symptom impacts of pediatric head and neck lymphatic malformations: developing a patient-derived instrument. Otolaryngol Head Neck Surg. 2012;147(5):925-931.


Ms Levandoski is a fourth-year medical student at Johns Hopkins University School of Medicine, Baltimore, Maryland. Dr Cohen, section editor for Dermcase, is professor of Pediatrics and Dermatology, Johns Hopkins University School of Medicine, Baltimore. The author and section editor have nothing to disclose in regard to affiliations with or financial interests in any organizations that may have an interest in any part of this article. Vignettes are based on real cases that have been modified to allow the author and editor to focus on key teaching points. Images also may be edited or substituted for teaching purposes.

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