Four-limb lymphoscintigraphy was performed on patients with YNS and on healthy, age-matched controls. All 17 patients had lower limb swelling, and 14 (82%) had upper limb swelling also, including 5 (29%) with hand involvement. None of the YNS lymph scans was completely normal. Combined qualitative and quantitative assessment showed that 67% of YNS scans were clearly abnormal compared with 36% of healthy control scans. Mean axillary and ilio-inguinal nodal tracer uptakes were 41%-44% lower in the YNS group than in the controls (p < 0.0001).
YNS is a lymphatic phenotype because lymphatic insufficiency was found to exist in all patients and the insufficiency was widespread (upper and lower limbs), with a common mechanistic fault of poor transport. The origin of the lymphatic fault is unclear. In healthy individuals, lymphatic abnormalities may be relatively common in the fifth decade of life onward.