| Children hereditary multiple osteochondroma (HME) is a genetic bone disease affecting the process of normal cartilage bone. This disease is the most common benign bone tumor in children. The incidence of HME is about1/50000, the incidence in male is higher than female, the ratio of male to female is approximately3:1. The tumor of children HME is consisted of the cap-like structure of cartilage tissue and the prominent bone tissue which is almost perpendicular to the bone surface. Children HME used to appear mostly around the joints, such as the metaphysis of long bones, ribs, scapula, pelvis, etc. The characteristic of the tumor is having a cartilage cap in the top of the tumor, the tumor continued to grow through its deep cartilage bone formation, tumor growth can cause local pain, bone deformities, movement disorder when the tumor is near joints, compress the adjacent blood vessels and nerves then cause corresponding symptoms. If the tumor suddenly grew up or rapid growth, malignant changes of the tumor should be considered. Many scholars have depth study of the HME from the genetic disease genes, pathogenesis, clinical manifestations and genotyping, imaging, and excessive cartilage cap growth has been considered to be one of the main reasons of the HME malignant transformation. ObjectiveWe observe the ultrastructure of children HME’s cartilage cap by scanning electron microscopy and transmission electron microscopy, in order to improve the understanding of the ultrastructural pathology of children HME, explore the pathogenesis of the disease, provide diagnosisreliable basis for children HME Ultrastructural pathologic, evaluate the reasons for the recurrence of children HME, and to provide some guidance for surgical treatment.Methods1. MaterialExperimental groups:select32HME childern in the pediatric orthopedic ward of our hospital between October2010and June2012. Control group:Select32cases of multi-fingered children, due to surgical resection of multi-fingered epiphyseal cartilage. The control group and the experimental group matched on age, gender, specimen processing methods; clear history of familial; preoperative examination without metabolic system and other bone diseases. The above cases were confirmed by the hospital ethics committee approval and their families signed informed consent.2. Methods The tumor cartilage cap or multi-finger normal cartilage were freshed with saline, then fixed in10%formalin solution, making the optical microscope slice, observe the structural by light microscopy.Wash the tissue with phosphate buffered saline or saline after removal of the take the HME cartilage cap and multi-finger normal cartilage specimens surface fixtures. Then fixed the specimens in glutaraldehyde (25g/L) at4℃for2h immediately. Required according to the needs of the experiment made into a scanning electron microscopy and transmission electron microscopy specimens, to prepare for experimental applications. Results1. Multi-finger normal cartilage and children the HME patients the tumor of cartilage cap observed by light microscopyMulti-finger normal cartilage HE staining observed by light microscopy: Microscopically perichondrium and cartilage tissue near the perichondrium were scattered distribution, small volume, chondrocytes were flat; tissue deep the visible split hyperplasia, increased volume, washomologous group distribution of cartilage cells, cartilage lacunae obvious cartilage matrix the homogeneous-shaped distribution, purple-blue.Children’s the HME tumor cartilage cap observed by light microscopy:the cartilage cap visible on the surface of a pink fibrous periosteum; cartilage cells in the crypts, often perpendicular to the basal bone arranged in columnar formation of cartilage and bone in the base of them.2. Scanning electron microscopy of multi-finger normal cartilage and children HME patients tumor cartilage capThe control group (multi-finger normal cartilage):freeze-fracture of the cartilage tissue seen in a small number of chondrocytes in cartilage space within the cell is round or irregular, the cell had small bumps on the surface; cartilage surface a large number of scattered, sparse collagen fibres.Experimental group (children HME the tumor cartilage cap):freeze-fracture of the cartilage tissue to see a large number of irregular cartilage lacunae, each lacuna containing cartilage cells, cell proliferation significantly larger chondrocytes irregular shape abundant cells, cell surface protrusions; the dense structure of the collagen fibers of the cartilage tissue surface compared to the control group.3. Transmission electron microscopy observations of multi-finger normal cartilage and children HME patients tumor cartilage capControl group (multi-finger normal cartilage):a small number of chondrocytes, the cells were mostly oval cells in the surface of a small amount of short microvilli, nucleus irregularly shaped nuclear chromatin condensation, edge set; visible cytoplasmto a small number of cells, the rough endoplasmic reticulum into cord-like dispersed in the cytoplasm, mitochondria smaller glycogen granules were clustered distribution.Experimental group (children HME the tumor cartilage cap):a large number of tumor-like cell hyperplasia, tumor cells larger aggregated distribution; nuclei were larger nuclei rich in euchromatin, prominent nucleoli, nucleoplasm; visible cytoplasm to round or oval mitochondria and expansion of the rough endoplasmic reticulum, a small number of lysosomes; tumor cells can be seen between the capillaries, vascular cavity filled with red blood cells and plasma proteins, cells, some protein-like substances deposited; cartilage cells, cartilage cell volume increased significantly compared with the control group increased fusiform morphology, the nucleus round nuclear euchromatin rich, prominent nucleoli can be seen near the tumor-like cells; cytoplasm can be seen within a large number of rough surface endoplasmic reticulum, rough endoplasmic reticulum was pool-like expansion, expansion tanks filled with fine granular material:the small number of mitochondria, free ribosomes can frequently be seen.Conclusions1. The cartilage cap in Children HME tumor cartilage metabolism,the cell proliferation and protein synthesis are active, some the tumor the cartilage caps collagen fiber dense calcification tendency has certain material foundation of the tumor malignant, child HME genetic disease, development, and outcome factors closely related.2. The cartilage cap in Children HME is the root of malignant transformation and recurrent. |
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