Histological Study Of Periosteum In NF1-CPT And Non NF1-CPT Lesions

Object: The pathological periosteum of congenital pseudarthrosis of tibia(CPT)was studied histologically,summarizing the gross and histomorphological characteristics of the pathological periosteum,identifying the specific changes of periosteal vessels,whether there is nerve fiber tissue in the periosteum,is there any difference between the pathological periosteum of children with neurofibromatosis type 1(NF1)and those without NF1,to explore the possible etiology of CPT and provide reference for treatment.Methods: The pathological periosteum of 40 patients with CPT in the experimental group was collected.Among them,20 cases were in the NF1-CPT group,and the other 20 cases were in the non NF1-CPT group.The tibial periosteum of 5 patients with cerebral palsy were collected in the control group.First,the general morphological characteristics of the specimens were described.Then HE staining was performed on the tissue sections,describing the histological features under a microscope,calculating and comparing the average vascular density of each group.Finally,immunohistochemical staining of PGP9.5,CD34 and PCNA was performed,comparing positive expression of PGP9.5,CD34 and PCNA in each group.Results:(1)The morphological characteristics of periosteum in NF1-CPT group and non NF1-CPT group were similar,all show obvious thickening of the pathological periosteum,compression and invasion of the tibia,leading to gradual atrophy of the tibia,tapered,medullary cavity occlusion.In NF1-CPT group and non NF1-CPT group,the pathological periosteum was mainly composed of a large number of well differentiated fibroblasts,fibrocytes and proliferative collagen fibers,fibrous tissue with hyaline degeneration and focal myxoid degeneration.(2)The pathological periosteum was accompanied by local vascular hyperplasia,the wall of proliferative vessels was thickened,and the lumen was very narrow,showing fissure like,even tending to occlusion.There was no significant difference in mean vascular density among NF1-CPT group,non NF1-CPT group and control group(P > 0.05);there was no significant difference in mean optical density of CD34 positive expression sites among NF1-CPT group,non NF1-CPT group and control group(P > 0.05).(3)There was nerve fiber tissue in the periosteum,but there was no abnormal nerve fiber hyperplasia.There were significant differences in mean optical density between NF1-CPT group and control group,non NF1-CPT group and control group(P < 0.05).(4)There were significant differences in PCNA semi quantitative analysis results between NF1-CPT group and non NF1-CPT group,NF1-CPT group and control group,non NF1-CPT group and control group(P < 0.05).Conclusions:(1)The lesions of periosteum were thickened obviously,which formed compression and invasion on tibia,led to tibia atrophy and tip gradually,and the pulp cavity was blocked,mainly composed of highly differentiated fibroblasts,fibroblasts and collagen fibers.(2)The vascular wall of the hyperplastic vessels was abnormally thickened,and the lumen was very narrow,showing fissure shape,even tending to occlusion.(3)There were nerve fibers in the periosteum,but no abnormal nerve fiber hyperplasia.(4)There was no significant difference in gross morphology,histomorphology and histopathological characteristics of blood vessels and nerves between CPT patients with NF1 and CPT patients without NF1.