Indocyanine Green Lymphography to Diagnose Primary Lymphedema and the Incidental Discovery of Primary Asymptomatic Lymphatic Insufficiency

PURPOSE

Lymphedema is an abnormal collection of protein-rich fluid in the interstitium resulting from the obstruction of lymphatic drainage. This process results in swelling, pain, and/or limited range of motion in the upper and lower extremities – most commonly seen in the arm and hand after lymph node surgery and radiation therapy for breast cancer treatment. The diagnosis of primary lymphedema has conventionally been made clinically. Primary, or congenital, lymphedema is diagnosed when no disease-triggering, traumatic, or iatrogenic surgical event may be identified in a patient’s history.¹ With sensitivity and specificity superior to lymphoscintigraphy, indocyanine green (ICG) lymphography makes image-based diagnosis of primary lymphedema possible.^2-5 We aimed to study our experience using ICG lymphography to diagnose primary lymphedema.

METHODS

The database from October 2015 to September 2016 at the University of Iowa Center for Lymphedema Research and Reconstruction was reviewed. Our retrospective analysis included patient history, clinical assessment, and diagnostic workup with lymphedema Q score, bioimpedance spectroscopy, and ICG lymphography of both upper and lower extremities.

RESULTS

46 patients were diagnosed with primary lymphedema based on both history and ICG lymphography. Interestingly, 6 patients (13%) were initially referred to us with the diagnosis of acquired disease but were subsequently found to have lymphographically confirmed primary disease. 15 patients (33%) were incidentally found to have lymphographically confirmed disease in the contralateral limbs which were completely asymptomatic. Furthermore, 4 patients (9%) had additional asymptomatic disease found in a third limb. All patients were triaged to receive severity appropriate treatments including complete decongestive therapy, lymphaticovenular anastomosis, vascularized lymph vessel transfer, and/or suction assisted lipectomy.

CONCLUSIONS

This study demonstrated the effectiveness of ICG lymphography in diagnosing primary lymphedema. We incidentally discovered a previously unrecognized pathologic entity – primary asymptomatic lymphatic insufficiency – which potentially explains the inconsistent pathogenesis of lymphedema following oncologic interventions, as these patients may be more likely to develop lymphedema compared to their healthy counterparts due to pre-existing disease. This pathologic entity also raises caution over performing lymphatic tissue transfer in patients with primary disease, as transfer surgery may be the last straw necessary to cause lymphedema in the donor region. Further investigation is warranted.

REFERENCES

1) Yamamoto T, et al. Indocyanine green lymphography findings in primary leg lymphedema. Eur J Vasc Endovasc Surg. 2015; 49(1):95-102.

2) Mihara M, et al. Indocyanine green (ICG) lymphography is superior to lymphoscintigraphy for diagnostic imaging of early lymphedema of the upper limbs. PLoS One. 2012; 7(6):381-382. 

3) Akita S, et al. Comparison of lymphoscintigraphy and indocyanine green lymphography for the diagnosis of extremity lymphoedema. J Plast Reconstr Aesthet Surg. 2013; 66(6):792-798.

4) Yamamoto T, et al. The earliest finding of indocyanine green lymphography in asymptomatic limbs of lower extremity lymphedema patients secondary to cancer treatment: the modified dermal backflow stage and concept of subclinical lymphedema. Plast Reconstr Surg. 2011; 128(4):314-321. 

5) Hara H, et al. Comparison of indocyanine green lymphographic findings with the conditions of collecting lymphatic vessels of limbs in patients with lymphedema. Plast Reconstr Surg. 2013; 132(6):1612-1618.