Yellow nail syndrome is a rare disease of unknown aetiology. Patients with YNS have a characteristic yellowish-coloured nails, pulmonary alterations and primary lymphedema. To the best of our knowledge, only a few reports of autopsy findings in these patients have been published. Its aetiology possibly involves a primary malformation of larger lymph vessels. We describe autopsy findings not previously associated with yellow nail syndrome, such as expansion of mediastinal lymph-nodes and splenic sinusoids. The present autopsy reveals hitherto unreported findings associated with YNS, such as alterations in splenic sinusoids and mediastinal lymph-node sinuses.

Yellow nail syndrome (YNS) is a rare disease manifesting as a triad of yellow-green dystrophic nails, lymphedema, and chronic respiratory disease. The etiology of YNS is obscure and investigations are few. A single lymphatic pathogenesis has been proposed to account for all the associated features, and despite the lack of evidence for a unifying lymphatic mechanism, this hypothesis prevails. The objective was to explore the lymphatic phenotype in YNS and to establish whether lymphatic dysfunction could be a major contributing factor to the disease process.
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.