Sinonasal mucosal vasculature in yellow nail syndrome and chronic rhinosinusitis with or without polyps

Lymphatic dysfunction is hypothesized to be an underlying factor in the pathophysiology of yellow nail syndrome (YNS) (yellow nails, lymphedema, pleural effusions, and frequently chronic rhinosinusitis [CRS]). It is unclear why some YNS patients develop CRS. We quantified lymphatic and total vasculature of sinonasal mucosa in YNS patients and compared it to controls from CRS patients with (CRSwNP) or without polyps (CRSsNP).

Immunohistochemistry was performed on archival sinonasal mucosal samples from 5 patients with YNS and 14 controls with antibodies against podoplanin and CD31, markers of lymphatics. Morphometric assessment was performed on digital images using ImageJ software.

In YNS, the number of lymphatics/mm² ranged from 7 to 18/mm² (controls: 6 to 43/mm² , p = 0.343), with a mean perimeter between 92 and 201 µm (controls: 42 to 280 µm, p = 0.482). Total vasculature density was higher than lymphatics, ranging between 189 and 1159 vessels/mm² , average 669 (controls: 139 to 1467/mm² , average 503, p = 0.257) with smaller average perimeter, 40 to 117 µm, mean 64.8 µm (controls: 42 to 92 µm, mean 65.3 µm, p = 0.965). Lymphatics constituted only a small fragment of the total vasculature, ranging from 1.15% to 4.76%, average 2.34% (controls: 0.81% to 10.58%, average 4.88%, p = 0.156). CRSwNP patients had significantly higher lymphatic density (p = 0.011) and ratio of lymphatics to total vasculature (p = 0.045) than patients with YNS or CRSsNP.

This is the first histological analysis of sinus mucosa in patients with YNS. Vascular type, density, size, and distribution in the sinonasal mucosa of YNS patients are not statistically significantly different from those of the CRSsNP group. Lymphatic density and ratio to total vasculature is higher in CRSwNP patients.