Bones Flashcards
Osteomalacia
Improper mineralisation due to Vitamin D deficiency
Failure to absorb fat soluble vitamins (secondary to chronic GI diseases)
In children called ¨rickets¨
decreased Ca —> increased PTH —>decreased phosphate —>apoptosis of chondrocytes
increased AP
decreased Ca
decreased phosphate
increased PTH
weakened bones, cupping and fraying of metaphysis
Endocrine and metabolic
Rickets
Improper mineralisation due to Vitamin D deficiency
High northern altitudes
Endocrine and metabolic
Hyperparathyroidism
Primary HPT due to hyperplasia or tumor of parathyroid gland that oversecretes PTH
Secondary HPT due to prolonged hypocalcemia and compensatory secretion of PTH
Stimulated osteoclasts increase bone resorption, resulting in decreased bone mass
Endocrine and metabolic disorders
Osteoporosis
Bone loss with aging occurs at a fairly uniform rate in men after 30
In women, follows same pattern until menopause when less estrogen leads to increase in interleukins 1 and 6 which stimulates osteoclasts
Proximal femur, distal radius, vertebrae
Endocrine and metabolic disorders
Paget Disease
Non integrated cycles of bone formation and absorption
Middle aged and elderly men
Early phase excessive bone resorption by osteoclasts
Mid phase excessive activity of osteoclasts and osteoblasts
Late phase dominated by excessive osteoblast activity
Bone thicker, but weaker
#1 symptom: PAIN
can lead to osteosarcoma or giant cell tumors
X ray is diagnostic
elevated IL6
large, multinucleated osteoclasts
Intrinsic non neoplastic
Osteopetrosis
osteoclasts produce H+ through carbonic anhydrase
encoded by the CA2 gene
any abnormality causing a dysfunction of osteoclasts will allow for unopposed osteoblast function
multiple fractures
bone marbling
Osteogenesis Imperfecta
Colllagen I abnormality
genetic
Type I: normal procollagen I production, but reduced MILD
Type II: replacement of glycine = abnormal matrix—> decreased trabeculae formation
blue sclera (made of Colagen I), thinned out
dentin affected
fractures
bisphosphatases
Osteosarcoma
teenagers and young adults around knee irregular bone destruction, which may include break through of cortex and associated soft tissue mass periosteal reaction with "sunburst" Codman sign aggressive gray white mass, may be hard mitotic activity, malignant osteoblasts lung mets chemotherapy malignant bone forming tumor
Osteoid osteoma/osteoblastoma
teenagers and young adults
osteoma -long bones <2cm
osteoblastoma - spine >2cm
well circumscribed, lytic (osteoid osteoma also can have sclerotic rim)
randomly arranged trabeculae of woven bone
osteoid osteoma - radiation
osteoblastoma- resection (radiation –> malignant change)
benign tumor of the bone
Osteochondroma
metaphysis adjacent to growth plate
long bones
any age, usually stops growing when growth plate closes (cont. growth after this —>chondrosarcoma)
bony stalk arisng from underlying bone, covered with benign cartilage
may be multiple (“osteochondromatosis” - autosomal dominant)
surgical resection if large and symptomatic
benign cartilage forming tumor
Chondroma
medullary cavity of bone )”endochrome”) or on surface of bone (“juxtacortical chondroma”)
young adult to middle aged
small bones of hands and feet, may be complicated by pathologic fracture
well circumscribed lytic lesion
mass of benign cartilage
may be multiple (“endochondromatosis” aka Ollier disease) risk of malignant transformation
surgical resection
benign cartilage forming tumor
Chondrosarcoma
malignant neoplasm of chondrocytes
older adults >40
irregularly destructive lytic lesion within bone, sometimes with speckled calcification
may extend into soft tissue surrounding the bone
often recognizable as cartilage, with translucent bluish gray tissue and a lobulated periphery (calcification frequently at periphery)
varying degrees of differentiation:
increased nuclear size, greater # of cells, less matrix
surgical resection
Giant Cell Tumor of Bone
osteoclast origin, usually benign
ages 20-40
metaphysis and epiphysis (extends to the surface with articular cartilage)
lytic, well circumscribed lesion that erodes adjacent cortex
mononuclear cells and abundant multinucleated giant cells
surgical resection
Ewing Sarcoma
maligant neoplasm of primitive mesenchymal cells
children and young adults
distal femur or proximal tibis
irregularly destructive, lytic lesion which may have a disproportionately large soft tissue mass relative to the amount of bone involvement
gray-white solid tumor
small blue round cell, may grow in sheets, no matrix produced by cells
FLI1 fused to EWSR1 produces transcriiption factor –>uninhibited cell proliferation
stain with CD99 to differentiate
chemo followed by resection
Multiple Myeloma
malignnt neoplasm of plasma cells
older adults
hematopoietically active bone (spine, pelvis, skull and ribs)
punched out lesions
sheets of monoclonal plasma cells that only express a single light chain
chemotherapy
