Pathological Observation Of Lymphatic Malformation In Soft Tissue And Investigation On The Expression Of MTOR Signal Pathway

Objectives: This research was designed to observe the pathological structures of lymphatic malformations(LMs),investigate the expression of m TOR signal pathway in the LMs,and discuss the role of m TOR signal pathway in the development of LMs.Methods: A retrospective chart review was performed including patients diagnosed as lymphatic malformations between Jan.2008 and Dem.2017.These patients underwent sclerotherapy,laser therapy and/or surgical resections.Resected lymphatic malformation samples from 3 of the patients were further investigated.Normal skin samples from other patients without LMs were used as controls.H-E staining was conducted to observe the pathological structures of LMs.Immunohistochemical staining was conducted to investigate the expression of D2-40 in different subtypes of lymphatic malformations.Immunohistochemical staining was also conducted to investigate the expression of molecules in m TOR signal pathway---m TORC1,p70S6 K,p-p70S6 K,el F4EBP1 and p-el F4EBP1---in lymphatic malformations.Western blotting assay was performed to compare the phosphorylation level of m TOR signal pathway between lymphatic malformations and normal skins.Results: H-E staining showed that three subtypes of LMs---macrocystic,microcystic and mixed subtype,all consisted of dilated lymphatic vessels,but are different in the diameter and quantity of vessels.Expression of D2-40,a marker of lymphatic endothelial cells,was positive in all the subtypes.Expression of m TORC1,p70S6 K,p-p70S6 K,e IF4EBP1,p-e IF4EBP1 was positive in lymphatic endothelia of lymphatic malformations.No significant difference(P>0.05)was observed in the expression of m TORC1,p70S6 K,e IF4EBP1 between lymphatic malformations and normal skins while the expression of p-p70S6 K and p-e IF4EBP1 is significantly higher in lymphatic malformations than that in normal skins(P<0.05).Conclusions:(1)Different subtypes of lymphatic malformations share similar pathological structures and antigen profile.Difference in diameters indicate that the dilated lymphatic vessels originate from different segments of lymphatic system.(2)The m TOR signal pathway is abnormally activated in lymphatic malformations,which is possibly associated with the development of lymphatic malformations.The study provides evidence for treating lymphatic malformations by inhibiting m TOR signaling pathway.