The investigators chose to terminate the study due to participant attrition. Of the limited data evaluable, none of the patients experienced adverse events.

The investigators propose a pilot trial to obtain preliminary information regarding the safety and response rate of patients with symptomatic lymphatic malformations treated with oral Selenium. Information obtained in this pilot trial will be used to plan future phase 2 clinical trials.

Hypotheses:

• Selenium will be safe and efficacious in the treatment of adolescents and young adults with symptomatic lymphatic malformations
• Disease response will correlate with serum levels of selenium and blood levels of antioxidants essential to selenium metabolism.

Inclusion Criteria:

• Patients must have clinical and radiographic features consistent with a lymphatic malformation (LM). Patients with combined venous lymphatic malformations (CVLM) will be included if the predominant componet is lymphatic based on MRI. Both macrocystic and microcystic LM will be eligible. Tissue biopsy is required to confirm the presence of an abnormal lymphatic malformation.
• All patients diagnosed with lymphatic malformations between 14 and 30 years of age will be eligible.
• Patients must have lymphatic malformations with potential to cause morbidity including one or more of the following: Lymphedema, Coagulopathy, Chronic Pain, Recurrent Cellulitis (> 1 episodes/year), Ulceration and/or bleeding, Impairment of organ function, Visceral and/or bone involvement, or Disfigurement.
• Patients receiving previous systemic therapy, surgical, debulking, or sclerotherapy will be eligible eight weeks following completion of therapy if they meet all inclusion criteria.
• All patients and/or their parents or legal guardians must sign a written informed consent. All institutional FDA requirements for human studies must be met.

Exclusion Criteria:

• Younger than 14 years of age or older than 30 years of age
• Life-threatening complications related to LM
• Patients with preexisting renal, hepatic, or thyroid disorders
• Patients receiving a daily multivitamin supplement or other natural products that include selenium
• Patients that have received previous selenium therapy will not be eligible
• Women who are pregnant or breastfeeding