As an example of the need for long-term follow-up by specialty health care to adequately manage immunodeficient patients, we report the case of a patient with Wiskott-Aldrich syndrome who was lost to follow-up for 4 years to the immunology clinic and came back with a neck mass that was diagnosed as B-cell lymphoma. Patients with immunodeficiency are at high risk for the development of malignancy and autoimmune diseases and should be evaluated by a trained specialist with a frequency of not less than every 6 months.