Indocyanine Green Lymphographic and Lymphoscintigraphic Findings in Genital Lymphedema – Genital Pathway Score

Hisako Hara, MD, PhD, and Makoto Mihara MD, Lymphatic Research and Biology 2017

Click to read the abstract

Indocyanine Green Lymphographic and Lymphoscintigraphic Findings in Genital Lymphedema—Genital Pathway Score

Hisako Hara, MD, PhD, and Makoto Mihara MD, Lymphatic Research and Biology 2017

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 99mTc 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 GPS2 and 3, splash pattern and stardust pattern were in the genitalia, respectively, with dermal back flow 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.

Main findings

  • The lymphatic fluid flowed from the lower limb on the ipsilateral side to the genital region in most patients, there were a few who had lymphatic flow from the contralateral side.
  • They established a genital pathway score (GPS). This score is useful in determining the choice of treatment, because the direction of lymphatic flow is essential in the selection of treatment.
  • GPS 1, dermal back flow is observed in the genital region, but not in the inguinal region. In GPS 2, a splash pattern was observed in the genital region, with dermal back flow in the inguinal region. In GPS3, a stardust pattern was observed in the genital region, with dermal backflow in the inguinal region. GPS, genital pathway score.
  • For GPS 2 or 3, it may be adequate to perform lymphatico venous anastomosis or lymph node transfer on the ipsilateral side, to reduce the amount of lymphatic fluid flowing into the genital region.
  • Conventional ICG testing is not adequate to evaluate genital lymphedema. They injected additional ICG at the high or lower leg in those cases and obtained greater sensitivity.
  • The sensitivity was greater with ICG lymphography than lymphoscintigraphy.