Bone Neoplasm, Myelitis, Necrosis Flashcards
Characteristics of osteoma
Benign, slow growing
Most commonly arise on the surface of bones (facial bones, some long bones)
Associated with Gardner syndrome (Familial adenomatous polyposis FAP, multiple osteomas, GI polyps)
Osteoma histology
well circumscribed nodular growth distorting the smooth contour of the skull.
composed of mature lamellar bone
Osteoid Osteoma characteristics
Small (1cm), benign tumor
Arise from osteoblast and make osteoid (surrounded by a rim of reactive sclerotic bone)
Young Male 13-20
Cortex of the long bone (femur tibia) usually on diaphysis
Painful - nocturnal pain relieved by aspirin, most likely due to prostaglandin E2 produced by proliferating osteoblasts
Radiographic findings of osteoid osteoma
Intracortical
round radiolucency with cintral mineralization of osteoid
surrounded by abundant reactive bone
Osteoid osteoma Histology
Haphazardly interconnecting trabeculae of woven bone
rimmed and prominent osteoblasts
intertrabecular spaces filled by vascularized loose connective tissue
Osteoblastoma
Uncommon but histologically similar to osteoid osteoma
benign
no boney reactive rim
vertebral
larger than 2 cm
lass painful and pain does not respond to aspirin
10% recur and some become osteosarcoma
osteosarcoma
most common primary malignant tumor of bone
proliferation of osteoblast
Bimodal incidence Distibution
peak incidence in younger than 20 (75%) - Familial Rb, growth plate activity
second peak older adults - Paget’s, bone infarc, prior radiation
Osteosarcoma body distribution
Metaphyseal area of long bone Knee - 50% Shoulder - 10% Jaw - 8% Pelvis/hip - 15%
Osteosarcoma presentation
Highly aggressive - 10-20% have metastisis to long at time of diagnosis, 90% who die have mets to lungs, bone, brain and others
Complex molecular phenotype in: Rb, INK4a, TP53, MDM2, and CDK4
Subtypes of osteosarcoma
Site of origin
histological grade
primary or secondary preexisting disorder
histological features
Osteosarcoma key findigns
Tumor breaks through the cortex and lifts the periosteum off the bone - Codman triangle
Sunburst periosteal bony reaction
Osteosarcoma histology
Anaplastic malignant tumor cells with abnormal and mitotic figures and characteristic basophilic osteoid and bone
Strong alkaline phosphatase and/or osteocalcin
Osteochondroma characteristics
Also know as exostosis benign cartilage-capped tumor most common benign tumor of the bone late adolescent to early adulthood Male
Osteochondroma appearance (self described)
Little nubbin coming off on the diaphysis like a new head
Chondroma and Enchondromas characteristics
Well-circumscribed benign tumors of hyaline cartilage (enchondromas arise from medullary cavity, juxtacortical chondromas if arise on surface of bone)
Hands and feet
age 20-50
rarely over 2 cm
May erode adjacent cortex and expand bone
Olliers disease
Multiple lesions
mutations in IDH1 or IDH2 gene
large bumps along the joints of fingers: look like cysts or baloons under skin
Maffucci’s syndrome
familial, hemangiomas of the skin; increased risk of ovarian or liver cancer
cause unknown
Purple spots on hand
Chondrosarcoma
Malignant cartilage tumor
Second most common malignant matrix-forming tumor of bone
arise in the central skeleton: ribs, shoulder, medulla of pelvis
May arise from preexisting enchondroma or osteochondroma
Types: conventional, clear cell, dedifferentiated, mesenchymal
Chondrosarcoma histology
Tissue sis still recognizable as cartilage - chondrocytes within clear lacunae, surrounded by a bluish matrix
No orderly pattern - increased cellularity and atypia
Can see some chondrosarcomas invading and destroying bone
Ewing Sarcoma/PNET characteristics
Neuroectodermal malignant tumor - poorly differentiated round cell tumor
Ewing Sarcoma family tumors = Ewing + primitive neuroectodermal tumor (PNET)
Second most common bone sarcoma in children
younger than 20 yo
White, Male
Medullary cavity of diaphysis of long bone
very aggressive - presents with metastasis, treatment combination of surgery, chemo, and radiation
Ewing Sarcoma presentation
painful, tender, warm, swollen
Mimic infection - fever, elevated sed rate, anemia, leukocytosis
Radiographically “onion-skin” appearance, turnover grows and pushes periosteum in reactive bone formation
Ewing Sarcoma histology
Small round blue cells with glycogen-rich cytoplasm
resembles lymphocytes, oten confused with lymphoma or chronic osteomyelitis
Twice the size of lymphocytes, periodic acid-schiff positive (glycogen),
CHROMOSOME 11:22
stain for CD99
Giant Cell tumor characteristics
Multinucleated giant cells and stomal cells
majority benign but can be locally aggressive
Age: 20-40
Ephiphysis of long bones: tibia, femur
Treated by curettage or resection
Giant cell tumor facts
often destroy overlaying cortex
radiographically soap bubble appearance
Giant cell tumor histology
Minority of cells: neoplastic, primitive, osteoblastic precursors (High levels of RANKL, stimulate osteoclast activity)
Majority of cells: non-neoplastic osteoclasts and precursors
Fibrous cortical defect/Nonossifyig fibroma
Fibrous cortical defects usually found incidentally - spontaneous resolution within several years
Extremely common 30-50% of children under 2 y.o.
Small and eccentric in metaphysis of distal femur and proximal tibia
Grow 5-6 cm = nonossifying fibromas
fibrous displasia
localized developmental arrest: all components of normal bone present, do not differentiate into mature structures, arise during skeletal development
Distinctive, overlapping, types: Monostatic, Polystatic, Mazabraud syndrome (polystatic with myxomas) McCune-Albright syndrome: polystatic with cafe-au-lait skin pigmentation
Metastatic tumors
More common than primary tumors of bone
pathways of spread: direct extension, lymphatic or blood dissemination, intraspinal seeding via batson plexus
Axial skeleton
Radiographically: osteolytic (kidney, lung, GI, melenoma) osteoblastic (prostate and breat)
Osteomyelitis overview
pyrogenic bacterial infection
80-90% Staph aureus (may see E coli, N gonorrhoeae, H influenza, sickle cell = salmonella
Reach bone by: blood, extension from contiguous site, direct implant
Healthy children: blood to long bone, mucosal injury
Adults: open fractures, surgery, diabetic infection
Child osteomyelitis areas
infection in Knee (tibia, or femur), shoulder, wrist
Adult osteomyelitis location
infection in mid femur, vertebrae, foot
Child spread of infection
younger than 1 blood flow allows infection into epiphysis from diaphysis
up to 15 the infection is restricted to below the ephiphysis because of iteruption of vessels
Tubeerculous osteomyelitis
incidence higher in los/middle income countries
1-3% of individuals with pulmonary or extrapulmonary tuberculosis
present in localized pain, low-grade fever, chills and weight loss
tends to be more destructive than pyogenic osteomyelitis
tuberculous osteomyelitis histology
characterisitc caseating granulomas which cause progressive destuction of the bony trabeculae, necrosis
skeletal syphilis
Syphilis and yaws
rare today
slowly progressive, chronic, inflammatory disease
edematous granulomas containing numerous plasma cells and necrotic bone
spirochetes localize to areas of active enchondral ossification and in periosteum
skeletal syphilis key findings
extensive anterior cortical and periosteal thickening of the tibial diaphysis
saddle-shaped nasal deformity
Osteonecrosis
fairly common
infarction of bone marrow causing bone necrosis
occurs in medullary cavity, involve medulla or cortex
complications: osteoarthritis and fracture
Causes of osteonecrosis
alcohol abuse bisphosphonate therapy connective tissue disorder corticosteroid chronic pancreatitis dysbarism (the bends) gaucher disease infection pregnancy radiation therapy sickle cell crisis trauma tumors
