Diagnostic Accuracy of Lymphoscintigraphy for Lymphedema

Background: Lymphedema is the chronic enlargement of tissue due to inadequate lymphatic function. Diagnosis is made by history and physical examination and confirmed with lymphoscintigraphy. The purpose of this study was to (1) assess the accuracy of lymphoscintigraphy for the diagnosis of lymphedema and (2) determine characteristics of patients with false-negative tests.

Methods: Patients referred to our lymphedema program with “lymphedema” between 2009-2016 were reviewed. Subjects were assessed by history, physical examination and lymphoscintigraphy. Patient age at presentation, duration of lymphedema, location of disease, gender, previous infections, and lymphedema type were recorded.

Results: The study included 223 patients. Lymphedema was diagnosed clinically in 158 subjects and confirmed by lymphoscintigraphy in 152 (112 primary lymphedema, 40 secondary); 65 patients were thought to have a condition other than lymphedema and all had negative lymphoscintigrams (96% sensitivity, 100% specificity). A subgroup analysis of the 6 patients with clinical lymphedema but negative lymphoscintigrams was performed: all had primary lymphedema (3 infant-onset and 3 adolescent-onset). Four patients were male, 5 involved the lower extremity, and 3 had prior infections. Lymphedema type, duration of disease, and infection history were not different between patients with true positive and false negative lymphoscintigrams (p=0.5). Three patients with false-negative results underwent repeat lymphoscintigraphy and all exhibited positive studies consistent with lymphedema (the mean time interval between lymphoscintigrams was 2 years, range 1-2.5).

Conclusion: Lymphoscintigraphy is very sensitive and specific for lymphedema. No obvious factors are associated with a false-negative study. A patient with a high clinical suspicion of lymphedema and a negative lymphoscintigram should be treated for the disease and undergo repeat lymphoscintigraphy > 1 year later.