Lymphatic Vessel Diameter and Lymphosclerosis: Two Different Characteristics

We read with great interest the article entitled “Site specific evaluation of lymphatic vessel sclerosis in lower limb lymphedema patients” by Mihara, et al. ¹ This study included 1028 lymphatic vessels and revealed that sclerotic lymphatics are more frequently found in the proximal limb and nonsclerotic lymphatics in the distal region.

We have several comments on this study. Based on our experience of lymphatic surgery using over 7000 lymphatic vessels, it is not always true that lymphedema progresses according to NECST classification.^2–5 There are gaps especially between the ectatic type (dilated lymphatics) and the contraction/sclerosis type (nondilated lymphatics with thickened walls); for example, some sclerosis types evolve without the ectatic stage, and several ectatic types do not progress to the contraction/sclerosis stage. Some lymphatic vessels are significantly dilated with sclerotic, thick walls. While ectasia represents dilatation of lymphatic vessel diameter, contraction/sclerosis represents sclerotic change, tunica media hypertrophy, or increased thickness of vessel wall.

There are two different characteristics to be evaluated in the lymphatic vessel: diameter and sclerosis. Therefore, we should distinguish lymph sclerosis and diameter.^4,5 This study does not include multivariate analysis, although the number of lymphatics studied is sufficient. Our studies have shown different independent variables within the results of univariate and multivariate analysis, so the outome may be altered in the current study if multivariate analysis will be performed.^4,5

This study includes 1028 lymphatics, sufficient to perform multivariate analysis. Without multivariate analysis, the reported results of the study cannot be considered to have clinical utility.