骨关节疾病教学课件

1、Non-neoplastic disorders Osteoporosis Osteoporosis is a disease characterized by increased porosity of the skeleton resulting from reduced bone mass. Generalized osteoporosis may be primary, or secondary to a large variety of conditions. The primary forms of osteoporosis are senile and postmenopausa

2、l osteoporosis; the former affects all aging individuals, while the latter affects only women after menopause. The secondary osteoporosis is caused by endocrine disorders, gastrointestinal disorders, neoplasia, etc. and immobilization. Mechamism of osteoporosisMenopause AgingDecreased serum estrogen

3、 Decreased replicative activityIncreased IL-1, IL-6, of osteoprogenitor cells TNF levels Decreased synthetic activityIncreased expression of osteoblasts of RANK, RANKL Decreased biological activity Increased osteoclast of matrix-bound growth factors activity Reduced physical activityMorphology The h

4、allmark of osteoporosis is a loss of bone, which tends to be most conspicuous in parts of the skeleton containing abundant trabecular bone. In postmenopausal osteoporosis, the bone loss is often particularly severe in the vertebral bodies, which may fracture and collapse. The major microscopic chang

5、es are thinning of the trabeculae and widening of Haversian canals. Osteoclastic activity is present but is not dramatically increased. The mineral content of the remaining bone is normal, and thus there is no alteration in the ratio of minerals to protein matrix.Clinical Course 1. asymptomatic or p

6、ain until fracture 2. Thoracic and lumbar vertebral fractures 3. loss of height and various deformities, including kyphoscoliosis The art for bone loss estimation involves specialized radiographic techniques to assess density, e.g., dual-energy absorptiometry and quantitative CT. Osteomyelitis Osteo

7、myelitis are caused by bacteria. The offending organisms reach the bone by one of three routes: (1) hematogenous dissemination (most common); (2) extension from an infection in adjacent joint or soft tissue; or (3) traumatic implantation after compound fractures or orthopedic procedures. Overall, St

8、aphylococcus aureus is the most frequent causal organism.MorphologyAcute osteomyelitis induce an inflammatory reaction, and cause cell death. Entrapped bone undergoes early necrosis; the dead bone in infected sites is called a sequestrum. Bone necrosis and actinomycesChronic osteomyelitis: Chronic i

9、nflammatory cells become more numerous. Leukocyte cytokine release stimulates osteoclastic bone resorption, fibrous tissue ingrowth, and bone formation in the periphery. Reactive woven or lamellar bone forms a shell of living tissue around a segment of devitalized bone it is called an involucrum.inv

10、olucrum Infiltration of lymphocytes and plasma cells Clinical Features Osteomyelitis classically manifests as an acute systemic illness with malaise, fever, leukocytosis, and throbbing pain over the affected region. Symptoms can also be subtle with only unexplained fever, particularly in infants, or

11、 only localized pain. Chronicity may develop when there is delay in diagnosis, extensive bone necrosis, abbreviated antibiotic therapy, inadequate surgical debridement, and/or weakened host defenses. Rickets and osteomalacia Rickets and osteomalacia are disorders characterized by a defect in matrix

12、mineralization, most often related to a lack of vitamin D or some disturbance in its metabolism. The term rickets refers to the disorder in children in which deranged bone growth produces distinctive skeletal deformities. In the adult the disorder is called osteomalacia, because the bone that forms

13、during the remodeling process is inadequately mineralized. Causes of Rickets and osteomalacia1. Deficiency states: diet; lack of sunlight2. Gastrointestinal causes: gastric resection; biliary and enteric causes3. Renal tubular causes: Hypophosphatemic states Fanconi syndromes End organ defect Renal

14、tubular acidosis4. Unusual causes: Phosphaturic tumors Anticonvulsant therapy5. Renal osteodystrophy: renal failure There is insufficient ionized calcium or inorganic phosphate (or both) to mineralize the skeleton, leading to less mineralized bone per unit volume of bone. Trabeculae are surrounded b

15、y unmineralized osteoid. In rickets, pressure effects cause deformity at the epiphysis-mataphysis junction, resulting in metaphyseal flaring and a disordered physis.MorphologyDeformity at the epiphysis-metaphysis junctionRachitic rosary due to accumulation of osteoidNeoplastic disorders Primary bone

16、 tumors exhibit great morphologic diversity and clinical behaviorsfrom benign to aggressively malignant. Most are classified according to the normal cell of origin and apparent pattern of differentiation. Clinically, benign lesions are frequently asymptomatic. Others produce pain or a slowly growing

17、 mass. Occasionally, a sudden pathologic fracture is the first manifestation. Radiologic imaging is critical in the evaluation of bone tumors; however, biopsy and histologic study are necessary for the final diagnosis. WHO classification 1. Cartilage tumors 2. Osteogenic tumors 3. Fibrogenic tumors

18、4. Fibrohistiocytic tumors 5. Ewing sarcoma/PNET 6. Haematopoietic tumors 7. Giant-cell tumors 8. Tumors of undefined neoplastic natureOsteogenic tumors Osteoma Osteomas are benign lesions of bone that in many cases represent developmental aberrations or reactive growths rather than true neoplasms.

19、They are most commonly encountered in the head and neck, including the paranasal sinuses.Morphology Osteomas are usually solitary and present as localized, slowly growing, hard, exophytic masses on the bone surface. Histologically, osteomas are a bland mixture of woven and lamellar bone.Lamellar bon

20、eWoven boneOsteomas on the bone surface Osteosarcoma Osteosarcoma is a bone-producing malignant mesenchymal tumor. The most common type of osteosarcoma is primary, solitary, intramedullary, and poorly differentiated, producing a predominantly bony matrix, and spread hematogenously; at the time of di

21、agnosis, approximately 10% to 20% of patients have demonstrable pulmonary metastases. 75% of osteosarcoma patients are younger than age 20. Men are more commonly affected than women (1.6:1). Most tumors arise in the metaphyseal region of the long bones of the extremities, with almost 60% occurring a

22、bout the knee, 15% around the hip, 10% at the shoulder, and 8% in the jaw. Histologic typing Conventional osteosarcoma Osteoblastic osteosarcoma Chondroblastic osteosarcoma Fibroblastic osteosarcoma Telangiectatic osteosarcoma Small cell osteosarcoma Parosteal osteosarcoma Periosteal osteosarcomaMor

23、phology Grossly, osteosarcomas are gritty, gray-white tumors, often destroy the surrounding cortices, lifted the periosteum, and formed soft tissue masses on the bone. Histologically, the tumor cells vary in size and shape, and frequently have large hyperchromatic nuclei; bizarre tumor giant cells a

24、re common, as are mitoses. The production of mineralized or unmineralized bone (osteoid) by malignant cells is essential for diagnosis of osteosarcoma. The tumor cells produce high grade hyaline cartilageNote the anaplastic tumor cells, neoplastic bone, mitotic figures. Fibroblastic osteosarcoma Sma

25、ll cell osteosarcoma An osteosarcoma composed of small cells with variable degree of osteoid production. Prognosis of this type of osteosarcoma is worse than conventional ones. Telangictatic osteosarcoma A malignant bone-forming tumour characterized by large spaces filled with blood with or without

26、septa. Highly malignant tumor cells produce minimal amounts of fine, lace-like osteoid. Prognosis is similar to conventional osteosarcoma.Parosteal osteosarcoma Parosteal osteosarcoma is a low grade osteosarcoma which arises on the surface of bone. It consists of well formed bony trabeculae in a hyp

27、ocellular stroma.Parosteal osteosarcomaPeriosteal osteosarcoma Periosteal osteosarcoma is an intermediate grade chondroblastic osteosarcoma arising on the surface of bone. There are lobules of malignant-appearing cartilage with bone formation in the center of the lobules.Periosteal osteosarcomaCarti

28、lage tumors Osteochondroma Osteochondroma is a cartilagecapped bony projection arising on the external surface of bone containing a marrow cavity that is continuous with that of the underlying bone.Most cases appear in the first 3 decades. It is the most common bone tumor.Morphology The most common

29、site of involvement is the metaphyseal region of long bone. The tumor may be sessile or pedunculated and has three layers - outer perichondrium, cartilage cap and underlying bone. Chondromas Chondromas are benign hyaline cartilage neoplasm. They differ with respect to location and clinical features.

30、 Enchondroma and periosteal chondroma are sporadic whil enchondromatosis usually manifests as a congenital tumor syndrom. Chondroma affects mostly the small tubular bones. The long tubular bones, especially proximal humerus and proximal and distal femur, are next in frequency. Chondroma tissue is wh

31、it-grey and opalescent, and hypocellular, avascular tumor with abundant hyaline cartilage matrix. The chondrocytes are situated within lacunar spaces, have uniform small round nuclei.Morphology Chondrosarcoma Chondrosarcoma is a malignant tumor with pure hyaline cartilage differentiation. The majori

32、ty of patients are older than 50 years. The most common skeletal sites are the bones of the pelvis, femur and humerus. The cut surfaces of the tumor tend to have blue-grey or white color corresponding to the presence of hyaline cartilage. A lobular growth pattern is a consistent finding. The chondro

33、cytes are atypical varying in size and shape and contain enlarged, hyperchromatic nuclei. Binucleation is frequently seen.MorphologyMesenchymal chondrosarcoma is a rare malignant tumor characterized by a bimorphic pattern that is comosed of highly undifferentiated small round cells and islands of we

34、ll differentiated hyaline cartilage. Giant cell tumor It is a locally aggressive neoplasm of undefined neoplastic nature. The tumor is composed of sheets of neoplastic ovoid mononuclear cells interspersed with uniformly distributed large, osteoclast-like giant cells. The peak incidence is between th

35、e ages of 20 and 45.GCT typically affect the ends of long bones, especially the distal femur, proximal tibia, distal radius and proximal humerus.distal femur The appearance of an intact specimen is eccentric location and fairly well defined area of bone destruction. The tissue is usually soft and re

36、ddish brown. Blood filled cystic spaces are sometimes seen.MorphologyLarge haemorrhagic tumor of the distal femur with extensive cortical destruction and soft tissue extension. The characteristic histopathological appearance is of round to oval polygonal or elongated mononuclear cells evenly mixed w

37、ith numerous osteoclast-like giant cells which contain 50 to 100 nuclei.Malignancy in GCT is a high grade sarcoma arising in a giant cell tumor or at the site of previously documented GCT.Grade IGrade IIGrade III Ewing sarcoma/Primitive neuroectodermal tumor (PNET) Ewing sarcoma and PNET are defined

38、 as round cell sarcomas that lack evidence of neuroectodermal differentiation (Ewing sarcoma) and demontrate neuroectodermal features (PNET). Ewing sarcoma/PNET shows a predilection for male younger than 20 yrs. Ewing sarcoma/PNET tends to arise in the diaphysis or metaphyseal- diaphyseal portion of

39、 long bones. The tumor in bone and soft tissue is tan-grey and often necrotic and haemorrhagic. The tumor is composed of uniform small round cells with round nuclei containing fine chromatin, scanty clear or eosinophilic cytoplasm, and indistinct cytoplasmic membranes. In PNET, Rosette-like structur

40、es are occasionally found. Immunohistochemical expression of CD99 shows characteristic reactivity on the cell membranes.Morphology Fibrous dysplasia Fibrous dysplasia is a benign medullary fibro-osseous lesion which may involve one or more bones. The most common site of involvement in the gnathic (j

41、aw) bones, femur and tibia or other bones. Fibrous dysplasia may present in a monostotic or polyostotic form, and in the latter case, can be confined to one extremity or one side of the body or be diffuse. The lesions of fibrous dysplasia are well circumscribed, intramedullary, and vary greatly in s

42、ize. The lesional tissue is tan-white and gritty and is composed of curvilinear trabeculae of woven bone surrounded by a moderately cellular fibroblastic proliferation. The trabecular bone sometimes lacks prominent osteoblastic rimming. Cystic degeneration, hemorrhage, and foamy macrophages are othe

43、r common findings. Morphology Aneurysmal bone cyst Aneurysmal bone cyst is a benign tumor of bone characterized by multiloculated blood-filled cystic spaces that may present as a rapidly growing expansile tumor. Grossly, aneurysmal bone cyst consists of multiple blood-filled cystic spaces separated

44、by thin, tan-white septa. The walls are composed of plump uniform fibroblasts, multinucleated osteoclast-like giant cells, and reactive woven bone. Deposition of the bone typically follows the contours of the fibrous septa. Morphology Osteoarthritis Osteoarthritis, or degenerative joint disease, is

45、the most common joint disorder. It is an important cause of physical disability in individuals over the age of 65. The fundamental feature of osteoarthritis is degeneration of the articular cartilage. In most cases, osteoarthritis appears insidiously with age and without apparent initiating cause (p

46、rimary osteoarthritis). When osteoarthritis strikes in youth, there is typically some predisposing condition, such as previous traumatic injury, developmental deformity, or underlying systemic disease such as diabetes or marked obesity. In these settings the disease is called secondary osteoarthritis and often involves one or several predisposed joints. The earliest structural changes in osteoarthritis include enlargement, proliferation, and disorganization of the chondrocytes in the superficial part of the