Indocyanine Green Lymphographic and Lymphoscintigraphic Findings in Genital LymphedemaGenital Pathway Score

Background: Although genital lymphedema is a challenging disease, its mechanism is unclear. The aim of this study was to identify the lymphatic flow in genital lymphedema and establish a suitable examination for genital lymphedema. Methods: We injected phytic acid or albumin labeled with Tc-99m at the bilateral first web spaces of the feet of 47 patients for lymphoscintigraphy. For indocyanine green (ICG) lymphography, we injected ICG into the first web spaces of both feet and other points if necessary. We established a genital pathway score (GPS). In GPS 0, there was no dermal backflow in genitalia. In GPS 1, dermal backflow was observed in the genitalia, but not in the groin. In GPS 2 and 3, splash pattern and stardust pattern were in the genitalia, respectively, with dermal backflow in the groin. Results: Twenty-eight patients (59.6%) reported subjective symptoms of genital lymphedema. Accumulation of isotope in the genital region was observed on 32 sides (34.0%) in lymphoscintigraphy. On ICG lymphography, 37 sides were classified as GPS 0. Nine sides were GPS 1, which indicated that the lymphatic accumulation in the genitalia seemed to flow from the contralateral side. Twelve sides were GPS 2, and 36 were GPS 3. Dermal backflow was observed in 60.6% of patients. Chi-square tests showed a significant relationship between prior radiotherapy and the presence of genital lymphedema (p=0.046). Conclusions: A pathway from the inguinal lymph nodes to the genital region was observed on lymphoscintigraphy in genital lymphedema. The sensitivity was greater with ICG lymphography than lymphoscintigraphy.