Fluorodeoxyglucose-Positron Emission Tomography (FDG-PET) to Evaluate Autoimmune Lymphoproliferative Syndrome (ALPS) and ALPS-associated Lymphoma

INCLUSION CRITERIA: ALPS Patients without Lymphoma: Participants must: Fulfill current criteria for the diagnosis of ALPS as follows: Documented chronic nonmalignant lymphadenopathy and/or splenomegaly, and Greater than or equal to 1.5 percent TCR alpha/beta+ CD4- CD8- T cells in the peripheral blood. Be enrolled in ALPS Natural History Protocol 93-I-0063. Have clinical evidence of lymphadenopathy as defined by multiple palpable lymph nodes of at least 1cm or radiographic evidence of lymphadenopathy as defined by multiple lymph nodes of at least 1 cm on CT scan, during an evaluation at the NIH Clinical Center. Be 8 years of age or older. The study will be targeted to children 8 years of age or older and adults because younger children may not be able to stay still for the duration of the FDG-PET scan procedure. Sedation will not be used in children in this study, except for clinically indicated procedures such as FDG-PET scans in children with lymphoma. Be due for their routine [every 2 years] CT scan under protocol 93-I-0063, or be in need of a CT scan for medical reasons [e.g. marked change in adenopathy]. CT scan within 3 months prior to FDG-PET scan is necessary to locate the nodes for appropriate FDG-PET analysis. ALPS Patients with Lymphoma: Patients must: Fulfill current criteria for the diagnosis of ALPS as follows: Documented chronic nonmalignant lymphadenopathy and/or splenomegaly. Greater than or equal to 1.5 percent TCR alpha/beta + CD4- CD8 -T cells in the peripheral blood. Be enrolled in ALPS Natural History Protocol 93-I-0063. Have a histologically proven diagnosis of lymphoma, confirmed by the Laboratory of Pathology, NCI (Anatomic Pathology Dept, CC) whether yet treated or not. Lymphomas will be classified according to the WHO classification, using appropriate immunophenotypic and histological features. EXCLUSION CRITERIA: Patient will be excluded if any of the following are present: Concurrent infection or inflammatory disease (e.g., sarcoidosis), which itself often shows increased FDG uptake by PET and which could interfere with the interpretation of study results. Active neoplasia other than lymphoma. History of chemotherapy or radiation treated malignancy within 5 years prior to study procedure, except for lymphoma. Hyperglycermia (regardless of etiology) determined by fasting glucose of greater than 130 mg/dl. Individual with an underlying defect of glucose metabolism may exhibit abnormal metabolism of FDG. Weights in excess of 136 kg, which will exceed the weight limit for the scanner table. Pregnancy and breast-feeding. For women of childbearing potential, a negative urine or serum pregnancy test is required within 24 hours prior to an FDG-PET scan.