Musculoskeletal II Revision PDF

Musculoskeletal II Revision Prof. Dr. Ahmed Naeem Associate Professor Of Pathology  ACUTE HEMATOGENOUS OSTEOMYELITIS Pathological Features: *Suppurative focus in metaphysis Endosteum → periostum (subperiosteal abscess)...

Musculoskeletal II Revision Prof. Dr. Ahmed Naeem Associate Professor Of Pathology  ACUTE HEMATOGENOUS OSTEOMYELITIS Pathological Features: *Suppurative focus in metaphysis Endosteum → periostum (subperiosteal abscess) → sinuses → cloaca (chronic) *Bone necrosis (toxins & ischemia) → sequestrum (separation) & involucrum (Thickening)  ACUTE HEMATOGENOUS OSTEOMYELITIS Complications: 1) Pathological fracture 2) Spread: Direct (arthritis, myositis, neuritis) Blood (toxaemia, septicaemia, pyemia) 3) Chronic: Amyloidosis Squamous cell carcinoma (sinus epith.) ACUTE NON-HEMATOGENOUS OSTEOMYELITIS Aetiology: 1- Infection of a fractured bone. 2- Infection of skull bones due to direct spread e.g mastoiditis in case of otitis media. Pathology: resembles the hematogenous type except for *Different location. *Absent subperiosteal abscess.  CHRONIC NON SPECIFIC OSTEOMYELITIS 1- Chronic osteomyelitis: ← acute osteomyelitis. 2- Brodie’s Abscess: localized - Staph. aureus - Young - No preceding acute - Small - Intraosseus - Cortical - Surrounding reactive sclerotic bone - Complicated by amyloidosis & fracture.  CHRONIC SPECIFIC OSTEOMYELITIS TUBERCULOSIS OF BONE Tuberculosis of long bone: Metaphysis → subperiosteal cold abscess → tuberculous arthritis. Tuberculosis of vertebrae (Potts Disease): - Hematogenous - Lower thoracic & upper lumbar followed by cervical -Two or more adjacent vertebrae are destructed and replaced by caseous material as well as the intervertebral disc (DD. Metastasis). -Potts disease is characterized by: 1) Kyphosis: due to anterior collapse of destroyed vertebrae. 2) Cold abscess: collection of caseous material - Cervical region: retro-pharyngeal. - Lumbar region: lumbodorsal triangle or in femoral triangle (through psoas sheath). 3) Paraplegia: - Spinal cord compression -Traumatic cord injury by fractured vertebrae.  Osteoid osteoma Benign tumor of bone arising mainly in the cortex less common in the medullary cavity Sites: Femur and tibia are the commonest sites Gross picture: solitary, less than 2cm in diameter, pink in colour with gritty sensation Complications: painful specially at night, it is due to excess production of prostaglandin E2 so that, pain is markedly improved by aspirin.  Compact osteoma Benign tumour arising in membranous bones of the skull Grossly: hard rounded ivory non capsulated Complications: -Disfigurement if it arises from outer table of the skull -Pressure symptoms if it arises from inner table Compact osteoma (ivory osteoma) of skull Skull  Chondroma Benign tumour of cartilage Most commonly in short bones of hands and feet, less common at end of long bones and flat bones as pelvis, sternum Gross picture: A rounded mass nodular surrounded by thin capsule, bluish and translucent Microscopic picture: Cartilage cells inside their lacunae. The chondrocytes are rounded with vacuolated cytoplasm Chondroma  Osteochondroma (exostosis) It can be considered as a developmental tumour like mass (hamartoma) rather than true neoplasm. It arises as lateral growth from epiphyseal cartilage of long bones and stops growth at puberty Gross picture: single or multiple exostosis. The lesion appears as mushroom-shaped lateral projection composed of bony stalk and a head formed of cartilaginous cap. Microscopic picture: cancellous bone covered by cartilage Malignant transformation is more common in case of multiple exostosis.  Chondroblsatoma It is an uncommon benign epiphyseal tumor of long bones of young adults. Grossly: It appears as a grayish pink growth expanding the affected end of long bone. Microscopically: Immature looking cartilage with characteristic “chicken wire” calcifications. Chondroblastoma  Chondromyxoid fibroma An uncommon benign tumor of young adults. Commonest in metaphysis of long bones. It consists of a mixture of cartilage, myxoid and fibrous tissue arranged in lobules.  Non-ossifying fibroma (also called metaphyseal fibrous cortical defect and benign fibrous histiocytoma). This tumor affects the metaphysis of long bones and consists of proliferated benign spindle cells as well as multinucleated giant cells and histiocytes. Non-ossifying fibroma  Ossifying fibroma (also called osteofibrous dysplasia) It predominantly affects the tibia of young children and is characterized by a mixture of proliferating spindle cells and active bone formation  Cemento-ossifying fibroma (cementoma) It affects craniofacial bones and consists of a mixture of proliferating spindle cells and globules of osteoid tissue that resemble cementum. Remark: Both of ossifying fibroma and cemento-ossifying fibroma are considered as variants of fibrous dysplasia Cemento-ossifying fibroma Cavernous hemangioma, Clavicle Intra-osseus lipoma  Locally malignant tumors of bones 1) Giant cell tumor (osteoclastoma) 2) Adamantinoma a) Mandible & maxilla (ameloblastoma) b) Long bone 3) Chordoma  Giant cell tumor of bone (osteoclastoma) Behavior: Locally malignant tumor (10-20% malignant). Age: >20 (may occur younger). Site: around knee (distal femur & proximal tibia) Involves both epiphysis & metaphysis. Origin: Unsettled (? Osteoblastic or fibroblastic).  Giant cell tumor of bone (osteoclastoma) Gross: - It usually forms an eccentric mass that erodes the subchondral bone. - The covering cortical bone becomes markedly thinned (egg shell-like). - The tumor tissue is grayish brown and frequently shows cystic degeneration. - Areas of hemorrhage are common.  Giant cell tumor of bone (osteoclastoma) Microscopic: Mononuclear tumor cells: (Neoplastic cells) Oval mononuclear stromal cells have dark nuclei with grades of atypia (mild to marked). Multinucleated giant cells: (up to 100 nuclei); osteoclastic type Non neoplastic cells (fusion of monocytes) Collagenous stroma, vessels and areas of hemorrhage.  Giant cell tumor of bone (osteoclastoma) Radiology: Eccentric lytic lesion. Adjacent thinned cortex. Minimal or no periosteal reaction. Spread: 80-90% of cases spread locally. 10-20% of cases metastasize by blood.  Adamantinoma of mandible & maxilla (Ameloblastoma) Behavior: Locally malignant; rare malignant (distant mets). Site: mandible & maxilla Intra-osseous or peripheral Origin: ameloblasts (tooth epithelium)  Adamantinoma of mandible & maxilla (Ameloblastoma) Gross: solid or multilocular cystic mass, resembling giant cell tumor. Microscopic: islands of odontogenic epithelium in a fibrous stroma  Adamantinoma of long bones Behavior: Locally malignant tumor; 20% malignant Site: Tibia Origin: Unsettled  Chordoma Behavior: Locally malignant; may malignant Age: >40 Site: Sacrococcygeal region Origin: notochordal remnants  Chordoma Gross: Infiltrative gelatinous mass  Chordoma Microscopic: It consists of cells with vacuolated cytoplasm and vesicular nuclei (physaliferous cells).  Chordoma Prognosis: Local recurrences after treatment are common. Finally the tumor sends distant metastases MALIGNANT BONE TUMORS  1- OSTEOSARCOMA It is the most common primary malignant tumor of bone. Origin: The neoplastic cells are osteogenic. Site:  Most common sites are ends of bones around knee joint.  The tumor starts within the metaphysis. Age:  Children and young adults  May occur in the elderly on top of Paget’s disease. Predisposing Factors: 1-Trauma. 2-Irradiation. 3-Paget’s disease of bone. 4-Fibrous dysplasia. 5-Osteochondroma Gross Features:  large mass extends within the medullary canal and destroys the bone cortex.  Extensive haemorrhage and necrosis. Microscopic Features:  Tumor cells are pleomorphic and include spindle and giant cell showing anaplastic features.  Matrix consists of osteoid tissue  Thin-walled vessels Radiological Features: Sun ray appearance Codman’s triangle. Spread & prognosis:  A highly malignant tumor rapid spread & poor prognosis.  Direct & blood spread.  2-CHONDROSARCOMA Chondrosarcoma is less common than osteosarcoma Origin : The neoplastic cells are chondrogenic. Site: most commonly in the central portions of the skeleton (pelvis, shoulder &ribs) Age: The 4th decade is the most common Predisposing Factors: 1-Paget’s disease of bone. 2-Fibrous dysplasia. 3-Chondroma 4- osteochondroma. Gross Features:  Grows within the medullary canal.  High grade tumors penetrate the cortex and periosteum  Areas of necrosis and hemorrhage.  Myxomatous and calcific changes are common Microscopic Picture:  Tumor cells show marked pleomorphism ,atypia &frequent mitosis in high grade tumors.  Hyaline matrix is more abundant in low grade tumors. Myxoid change and spotty calcifications are common.  Vascularity, hemorrhage and necrosis are more obvious in high grade tumors Radiological Features: Mottled densities due to spotty calcifications are commonly detected Spread:  Low grade chondrosarcoma spreads locally with no distant spread  High grade chondrosarcoma spreads directly and by blood (similar to osteosarcoma) Prognosis: Generally better than osteosarcoma  Fibrosarcoma Definition: uncommon bone tumor arises from periosteum. Site: Femur and tibia are common sites Gross: firm grayish mass Periosteal fibrosarcomasurrounds bone and may infiltrate bone cortex Medullary fibrosarcomaexpands medullary canal and erodes cortex and periosteum  Fibrosarcoma Microscopic: Pleomorphic spindle cells with low grade or high grade nuclear atypia, collagenous matrix and thin walled vessels. Hemorrhage and necrosis are more common in high grade tumors. Prognosis: slower in low grade with better prognosis High grade tumors spread by direct and blood routes. Fibrosarcoma  Plasma cell neoplasm ( Multiple myeloma) Definition: A malignant tumor arising from plasma cells occurring in bone marrow. Age: Adults > 40 years Sites: Skull, vertebrae, sternum, pelvis and ribs. Gross: The tumors appear as soft red nodules Issue 1/ 2018 1  Plasma cell neoplasm ( Multiple myeloma) Microscopic: Sheets of neoplastic plasma cells Radiological Features: Osteolytic destructive bone lesion and "punched-out lesions" in skull Issue 1/ 2018 1  Ewing’s sarcoma Definition: Ewing sarcoma is a malignant bone tumor characterised by primitive round cells without any differentiation. It is the second most common bone sarcoma in children after osteosarcoma Site: Medullary canal of diaphysis of long bones especially femur or flat bones of pelvis Clinical picture: painful tender swelling may be confused with osteomyelitis Issue 1/ 2018 1  Ewing’s sarcoma Gross: The tumor arises in the medullary canal and invades cortex, periosteum and soft tissue The tumor is soft, tan white, with frequent necrosis and hemorrhage Issue 1/ 2018 1  Ewing’s sarcoma Microscopic: Lesions composed of sheets of uniform small blue round cells with scant clear cytoplasm, rich in glycogen Issue 1/ 2018 1  Ewing’s sarcoma Radiological Features: Osteolytic destructive bone lesion periosteal reaction  layers of reactive bone deposition (onionskin-like fashion) Issue 1/ 2018 1  osteodystrophy Osteo = bone Dystrophy = abnormal changes in the growth and formation of an organ  1-FIBROUS DYSPLASIA Site: any bone. Forms: 1-Monostotic: single bone involvement. 2-Polyostotic: Multiple but never all bones. -Albright syndrome (mutation in GNAS1 gene): polyostotic with cafe au lait skin pigmentations and precocious puberty.  1-FIBROUS DYSPLASIA microscopic: fibrous tissue proliferation trapping thin irregular bone trabeculae.  1-FIBROUS DYSPLASIA  Complications: 1) Pathological fracture 2) Malignant transformation.  2-PAGET’S DISEASE  Aetiology: unknown aetiology, affecting old males. Very rare in Egypt.  Pathogenesis: “matrix madness”: furious osteoclastic bone resorption (osteolytic phase) hectic bone formation (osteoblastic phase) increased bone density (osteosclerotic stage) bone deformities (gain in bone mass, but bone is disordered with abnormal collagen ) a- Skull enlargement with narrowing of its foramina b- Bending of long bones.  2-PAGET’S DISEASE  Complications: 1- Pathological fracture 2- Sarcomatous transformation ( osteosarcoma, chondrosarcoma or fibrosarcoma)  3- osteoporosis  Definition: reduction in skeletal mass of normally mineralized bones, usually due to imbalance between bone resorption and bone formation so increased bone resorption or decrease bone formation may result in osteoporosis  Causes: 1- primary osteoporosis caused by : - Senility - Post menopausal women due to decrease estrogen - Decreased mobility 2- secondary osteoporosis due to Cushing syndrome or Prolonged corticosteroid therapy  Sites: wrist, hip and spines  3- osteoporosis hyperkyphosis  Pathology: Bones are thinned.  Complications: 1- Pathological fractures are common mainly vertebrae 2- Vertebral deformities may occur.  3- osteoporosis  Diagnosis: Bone mass index Test The greater the negative number the more severe the osteoporosis. A score between -1 and -2.5 low bone mass more than -2.5 osteoporosis  3- osteoporosis  How to limit or delay onset of osteoporosis: -changing style of life as eating healthy food rich in calcium, phosphorus, grains, spinach , protein in meat ,eggs and beans, vitamins, -stop smoking -regular daily excercise  4- others Hyperparathyroidism rickets ( disease of infants characterized by defective bone mineralization) i.e.calcium and phosphate resulting in bone softening and abnormalities of bone growth osteomalacia ( like rickets ) but occurs in adult due to repeated pregnancy and lactation.  TYPES OF ARTHRITIS 1- Acute arthritis : a-suppurative b- traumatic c- rheumatic d- viral e- acute gouty arthritis 2- Chronic arthritis: a- osteoarthritis (osteoarthrosis) b- rheumatoid arthritis c- chronic gouty arthritis d- tuberculous arthritis e- syphilitic arthritis f- Neuropathic arthritis (Charcot’s arthritis)  OSTEOARTHRITIS Osteoarthritis is a common degenerative disease characterized by primary abnormalities in the articular cartilage of weight bearing joints (knee & hip are the most common sites). It is a disease of elderly (females more common than males), it can affect younger patients secondary to a predisposing abnormality in the joint.  Osteoarthritis 1) Primary Osteoarthritis (95%); Old age; result of “wear and tear” of the joint. 2) Secondary Osteoarthritis (5%): It can affect any age due to one or more of the following causes: a- Chronic joint stress e.g. due to obesity and occupational strains. b- Abnormal joint mechanics  Osteoarthritis b- Abnormal joint mechanics : Congenital joint deformities angulations, malalignment Acquired joint defomities post-traumatic or postinflammatory injury Nerve supply affection to joint Charcot’s joint or due to spinal cord lesions (syphillis ) Systemic disease diabetes mellitus and hemochromatosis 1- Articular cartilage & bone lesions: Degeneration and softening of articular cartilage Central part of cartilage disappears expose bone Peripheral cartilage proliferation cartilaginous lippings Ossification of lippings  bony projections (osteophytes) Degenerated cartilage form (joint mice) The underlying bone undergoes progressive eburnation. 2- The synovium may show mild chronic inflammation and osteocartilagenous metaplasia  Rheumatoid arthritis  Autoimmune systemic disease affecting synovial joints; also skin, blood vessels, heart, lungs, muscles  Is the second most common type of arthirits  more common in females between 30-50 years  Genetic Environmental Autoimmune Pathophysiology  PATHOGENESIS: An autoimmune mechanism of unknown stimulus (post-viral or bacterial). Autoantibodies are liberated and excite an inflammatory reaction. Parvovirus B19 may be important in pathogenesis  The inflammatory cells release cytokines as TNF & interleukins as well as collagenase, proteases causing destruction of joint structures.  Gross & Microscopic Morphology of RA 1- Chronic inflammation of the synovial membrane: Gross Synovium becomes thickened, edematous, frond-like (villous) projections. Microscopy: Fibrinoid necrosis, Numerous lymphocytes, plasma cells & histiocytes, giant cells 2- Excessive Granulation tissue, Pannus. 3- Articular cartilage is destroyed by collagenase and other proteases released in pannus. This followed by fibrous or bony ankylosis, joints appear swollen, spindle shaped and deformed. Deformities 2- Extra-articular lesions a-Rheumatoid nodules: are subcutaneous nodules develop over bony prominences, commonly around elbow, measure from 1-2 cm in diameter. Microscopically: fibrinoid necrosis of collagen surrounded by palisading histiocytes. b- Heart lesions: Rheumatoid nodules affecting the valves and pericardium. c- Vascular lesions: Arteritis and even phlebitis may occur. d- Lymphoid hyperplasia and enlargement of lymph nodes and spleen. e) Amyloidosis may occurs.  Pigmented villonodular synovitis Def.: It is an uncommon disease characterized by proliferation of synovial membrane of joints, mainly knee. Age: Adults. Site: Knee joint (the commonest). Clinical: - Painful joint swelling. - Progressive joint disability Etiology: Unknown (inflammatory or benign tumor)  Pigmented villonodular synovitis Gross: - Synovial membrane is thickened. - Shows villous outgrowths. - Have a typical orange-brown color due to presence of hemosiderin.  Pigmented villonodular synovitis Microscopic: Villi - covered by proliferating synovial epithelial cells. - vascular connective tissue core infiltrated by large number of foamy histiocytes, histiocytes engulfing hemosiderin, lymphocytes, plasma cells and multinucleated giant cells.  Synovial Sarcoma (Malignant Synovioma) Site: Near a joint in the extremities, in particular, the knee and ankle joints. Gross: A grayish lobulated pseudo-capsulated mass with areas of necrosis, hemorrhage and cystic degeneration.  Synovial Sarcoma (Malignant Synovioma) Microscopic: Highly cellular neoplasm with a biphasic pattern composed of: Spindle cells + Epithelium-lined slit-like spaces.