Diseases of Bones

DISEASES OF DISEASES OF BONESBONES

Diseases Associated Diseases Associated with Abnormal Bone with Abnormal Bone

MatrixMatrix

OSTEOGENESIS IMPERFECTA (TYPE I OSTEOGENESIS IMPERFECTA (TYPE I COLLAGEN DISEASE):COLLAGEN DISEASE):

A group of A group of mainly autosomal dominantmainly autosomal dominant genetic disorders genetic disorders

resulting from defective synthesis of type I collagenresulting from defective synthesis of type I collagen due to due to

mutations in the gene for type I collagenmutations in the gene for type I collagen ..

Affected bones have thin bone cortices and trabeculae and Affected bones have thin bone cortices and trabeculae and are markedly fragile and easily broken. are markedly fragile and easily broken.

In addition to bone, other tissues rich in type I collagen are In addition to bone, other tissues rich in type I collagen are

also affected e.g. sclerae, teeth ears, joints and skinalso affected e.g. sclerae, teeth ears, joints and skin

OSTEOPOROSISOSTEOPOROSIS::

A condition in which the bone mass is A condition in which the bone mass is reduced below the level necessary reduced below the level necessary for normal bone functionfor normal bone function..

Pathogenesis: Pathogenesis: An excess of bone An excess of bone resorption over bone formation due resorption over bone formation due to increased resorption, decreased to increased resorption, decreased formation or bothformation or both..

CausesCauses::

11 . .Senility due to age-related decrease in Senility due to age-related decrease in osteoblastic activity (osteoblastic activity (senile osteoporosis)senile osteoporosis)..

22 . .Estrogen deficiency, mainly due to increased Estrogen deficiency, mainly due to increased osteoclastic activity (osteoclastic activity (postmenopausal postmenopausal osteoporosisosteoporosis))..

33 . .Excessive production or administration of adrenal Excessive production or administration of adrenal cortical hormones, due to decreased osteoblastic cortical hormones, due to decreased osteoblastic activityactivity..

44 . .Local factors e.g poliomyelitis, paraplegia or Local factors e.g poliomyelitis, paraplegia or immobilization of fractured bones, due to immobilization of fractured bones, due to decreased mechanical stimulation of osteoblastic decreased mechanical stimulation of osteoblastic activityactivity..

PathologyPathology::

Variable thinning of boneVariable thinning of bone

cortices and trabeculaecortices and trabeculae

with normal bonewith normal bone

mineralizationmineralization..

Effects/ComplicationsEffects/Complications::

11 . .Bone painsBone pains

22 . .Reduced height or even Reduced height or even kyphosis, duekyphosis, due

to vertebral collapseto vertebral collapse

33 . .Pathological fractures Pathological fractures following minor trauma, following minor trauma, mainly in neck of femur mainly in neck of femur and pelvic bonesand pelvic bones

Diseases due to osteoclastic Diseases due to osteoclastic dysfunctiondysfunction

OSTEOPETROSISOSTEOPETROSIS::

A goup of genetic disorders resulting A goup of genetic disorders resulting from osteoclastic dysfunction leading from osteoclastic dysfunction leading to diffuse bone sclerosisto diffuse bone sclerosis . .

The sclerotic bones are, however, The sclerotic bones are, however, fragile and easily fracturedfragile and easily fractured..


11 . .Defective bone remodeling with Defective bone remodeling with persistence of woven bonepersistence of woven bone

22 . .Marked thickening of bone cortices and Marked thickening of bone cortices and trabeculae with marked narrowing of trabeculae with marked narrowing of marrow spacesmarrow spaces

33 . .Narrowing of neural foramina with Narrowing of neural foramina with compression of exiting nervescompression of exiting nerves

PAGET'S DISEASE OF BONE (OSTEITIS PAGET'S DISEASE OF BONE (OSTEITIS DEFORMANS)DEFORMANS)::

A rare disease that probably results from A rare disease that probably results from osteoclastic dysfunction due to a slow osteoclastic dysfunction due to a slow virus infection by a paramyxovirusvirus infection by a paramyxovirus . .

The disease appears after the age of 40 The disease appears after the age of 40 years and may be familialyears and may be familial . .

It is usually generalized affecting the leg It is usually generalized affecting the leg bones, vertebrae and skull but may rarely bones, vertebrae and skull but may rarely be localized affecting mainly the tibiabe localized affecting mainly the tibia..


11 . .Early in the disease, there is Early in the disease, there is increased osteoclastic bone increased osteoclastic bone resorption with replacement of the resorption with replacement of the affected bones by poorly mineralized affected bones by poorly mineralized osteoid and highly vascularized osteoid and highly vascularized fibrous tissue leading to bone fibrous tissue leading to bone softening and deformity with softening and deformity with kyphosis and bowing of leg bones kyphosis and bowing of leg bones ((osteolytic phaseosteolytic phase))..

22 . .Later on, bone resorption gradually Later on, bone resorption gradually decreases and bone formation decreases and bone formation progressively increases leading progressively increases leading eventually to thickening and eventually to thickening and hardening of the deformed bones hardening of the deformed bones and the skull (and the skull (osteoblastic phaseosteoblastic phase). ). Microscopic examination of bone at Microscopic examination of bone at this stage shows thickened bone this stage shows thickened bone trabeculae with a characteristic trabeculae with a characteristic mosaic (jigsawmosaic (jigsaw puzzle)puzzle) appearance appearance..


11 . .Bone deformity (see above)Bone deformity (see above)22 . .Bone painsBone pains

33 . .Pathological fracturesPathological fractures44 . .Osteoarthritis due to abnormal stresses on the Osteoarthritis due to abnormal stresses on the

joints by the bone deformityjoints by the bone deformity55 . .Deafness due to compression of the 8th cranial Deafness due to compression of the 8th cranial

nerve by narrowed exit foramina in the skull nerve by narrowed exit foramina in the skull 6. Spinal cord compression by thickened vertebral 6. Spinal cord compression by thickened vertebral bodiesbodies

77 . .Osteosarcoma in 1% of casesOsteosarcoma in 1% of cases88 . .High output cardiac failure due to increased High output cardiac failure due to increased

venous return from the abnormal bonesvenous return from the abnormal bones99 . .Increased serum alkaline phosphataseIncreased serum alkaline phosphatase

Disease associated with Disease associated with Abnormal Bone MineralizationAbnormal Bone Mineralization

RICKETSRICKETS::

A bony disease of infants (6 months – A bony disease of infants (6 months – 2 years) resulting from vitamin D 2 years) resulting from vitamin D deficiency, most commonly due to deficiency, most commonly due to lack of exposure to ultraviolet rays of lack of exposure to ultraviolet rays of the sun (which changes the sun (which changes subcutaneous sterols to vitamin D)subcutaneous sterols to vitamin D)..

Bony manifestationsBony manifestations::

These result from failure of These result from failure of mineralization of bone with mineralization of bone with accumulation of excessive osteoid on accumulation of excessive osteoid on the surface of bone trabeculae the surface of bone trabeculae leading to abnormally soft bones. leading to abnormally soft bones. They They includeinclude::

11 . .Thickening of frontal and parietal bones Thickening of frontal and parietal bones of the skull (bossing)of the skull (bossing)

22 . .Delayed closure of skull sutures and Delayed closure of skull sutures and fontanellesfontanelles

33 . .Delayed eruption of teethDelayed eruption of teeth

44 . .Thinning of occipital bones (craniotabes)Thinning of occipital bones (craniotabes)

55 . .Pigeon chest: The sternum is pushed Pigeon chest: The sternum is pushed forwards with a longitudinal groove on forwards with a longitudinal groove on each sideeach side

66 . .Rickety rosary: The chest appears Rickety rosary: The chest appears "beaded" on each side due to enlargement "beaded" on each side due to enlargement

of the costochondral junctionsof the costochondral junctions

77 . .Harrison's sulcus: A transverse groove on Harrison's sulcus: A transverse groove on each side of the chest corresponding to each side of the chest corresponding to

the insertion of the diaphragm in the ribthe insertion of the diaphragm in the rib

88 . .Deformity of the lumbar vertebrae Deformity of the lumbar vertebrae in the form of kyphosis, lordosis in the form of kyphosis, lordosis or scoliosisor scoliosis

99 . .Narrow pelvic inlet: The sacral Narrow pelvic inlet: The sacral promontory is pushed forwards promontory is pushed forwards and the acetabula inwardsand the acetabula inwards . .

In females, this may lead to difficult In females, this may lead to difficult labor later onlabor later on

1010 . .Bowing of long bones (femur, tibia, Bowing of long bones (femur, tibia, radius, ulna)radius, ulna)

1111 . .Swelling of wrists, ankles and Swelling of wrists, ankles and knees due to widening of the knees due to widening of the epiphyseal platesepiphyseal plates

1212 . .MicroscopicallyMicroscopically there is there is::

a) Increased osteoida) Increased osteoid

on surfaces of poorlyon surfaces of poorly

mineralized bonemineralized bone

trabeculaetrabeculae

b) Irregular thickening of the epiphyseal b) Irregular thickening of the epiphyseal plates due to failure of osteoclastic plates due to failure of osteoclastic resorption of cartilage (consequent to resorption of cartilage (consequent to failure of mineralization of the carilage failure of mineralization of the carilage

matrix)matrix)

Extra-skeletal manifestationsExtra-skeletal manifestations::

11 . .Pot belly due to flabbiness of abdominal musclesPot belly due to flabbiness of abdominal muscles

22 . .Enlargement of spleen and lymph nodesEnlargement of spleen and lymph nodes

33 . .AnemiaAnemia

44 . .Low serum calcium and phosphorusLow serum calcium and phosphorus

Complications and causes of deathComplications and causes of death::

11 . .GastroeneteritisGastroeneteritis

22 . .BronchopneumoniaBronchopneumonia

OSTEOMALACIAOSTEOMALACIA::

A bony disease of adults resulting from A bony disease of adults resulting from deficiency of vitamin D and calciumdeficiency of vitamin D and calcium . .

It usually occurs in females following It usually occurs in females following repeated pregnancies andrepeated pregnancies and

is characterized by deformities of long bones is characterized by deformities of long bones and vertebrae and narrow pelvic inlet, and vertebrae and narrow pelvic inlet, consequent to bone softeningconsequent to bone softening..

OSTEITIS FIBROSA CYSTICA (von OSTEITIS FIBROSA CYSTICA (von RECKLINGHAUSEN'S DISEASE OF BONE)RECKLINGHAUSEN'S DISEASE OF BONE)::

A bony disease resulting from excessive A bony disease resulting from excessive secretion of parathyroid hormone by secretion of parathyroid hormone by hyperplasia or adenoma of the parathyroid hyperplasia or adenoma of the parathyroid glandsglands . .

Parathyroid hormone leads mobilization of Parathyroid hormone leads mobilization of calcium and phosphate from bone and calcium and phosphate from bone and increased resorption of calcium from the increased resorption of calcium from the bowelbowel..


Generalized bone decalcification and resorption Generalized bone decalcification and resorption associated withassociated with::

11 . .Increased osteoclastsIncreased osteoclasts

22 . .Focal replacement ofFocal replacement of bone by fibrous tissuebone by fibrous tissue that commonly undergoesthat commonly undergoes cystic degenerationcystic degeneration

33 . .Tumor-like masses composed of fibrous tissue, Tumor-like masses composed of fibrous tissue, abundant hemosiderin and numerous abundant hemosiderin and numerous osteoclasts (osteoclasts (brown tumorsbrown tumors))


11 . .Bone painsBone pains

22 . .Bone swellingsBone swellings

33 . .Pathological fracturesPathological fractures

44 . .Hypercalcemia, hypophosphatemia and Hypercalcemia, hypophosphatemia and increased serum alkaline phosphataseincreased serum alkaline phosphatase

55 . .Renal calculiRenal calculi

RENAL OSTEODYSTROPHYRENAL OSTEODYSTROPHY::

Bony changes seen in patients with Bony changes seen in patients with chronic renal failure particularly chronic renal failure particularly those receiving dialysisthose receiving dialysis..

PathogenesisPathogenesis::

11 . .Mobilization of calcium from bone due to Mobilization of calcium from bone due to secondary hyperparathyroidism consequent to secondary hyperparathyroidism consequent to phosphate retention resulting from decreased phosphate retention resulting from decreased glomerular filtrationglomerular filtration

22 . .Inadequate production of active vitamin D Inadequate production of active vitamin D metabolites by the failing kidneysmetabolites by the failing kidneys

33 . .Deposition of aluminum in bone, derived fromDeposition of aluminum in bone, derived from:: a) Dialysis solutions prepared from water with a a) Dialysis solutions prepared from water with a

high aluminum content high aluminum content b) Aluminum-containing oral phosphate bindersb) Aluminum-containing oral phosphate binders

Pathology:Pathology: The following changes may be seen The following changes may be seen separately or in variable combinationsseparately or in variable combinations::

11 . .Osteitis fibrosa cystica in 80 – 90% of patientsOsteitis fibrosa cystica in 80 – 90% of patients

22 . .Rickets/osteomalacia in 20 – 40% of patientsRickets/osteomalacia in 20 – 40% of patients

33 . .Increased bone density (osteosclerosis) due to Increased bone density (osteosclerosis) due to excessive formation of woven bone in 30% of excessive formation of woven bone in 30% of patientspatients

44 . .Amyloid deposition in bone and periarticular Amyloid deposition in bone and periarticular tissues in some patientstissues in some patients

Bone Infections Bone Infections (Osteomyelitis)(Osteomyelitis)

ACUTE SUPPURATIVE OSTEOMYELITISACUTE SUPPURATIVE OSTEOMYELITIS::

Acute suppurative inflammation of bone and Acute suppurative inflammation of bone and its soft tissues, namely, periosteum, its soft tissues, namely, periosteum, Haversian canals and bone marrowHaversian canals and bone marrow

Causative organismsCausative organisms::

11 . .Staph. aureusStaph. aureus: The commonest: The commonest

22 . .Other organisms: Streptococci, E. coli, H. Other organisms: Streptococci, E. coli, H. influenzae, Proteus, Pneumococci, typhoid influenzae, Proteus, Pneumococci, typhoid

bacillibacilli

Predisposing factorsPredisposing factors::

11 . .Trauma: This leads to a hematoma Trauma: This leads to a hematoma which provides a good medium for which provides a good medium for bacterial growthbacterial growth

22 . .Age and sex: Male children and Age and sex: Male children and adolescents are most commonly adolescents are most commonly affectedaffected

Routes (modes) of infectionRoutes (modes) of infection::

11 . .Blood borne infection from a septic focus Blood borne infection from a septic focus elsewhere in the body e.g skin boil, elsewhere in the body e.g skin boil, tonsillitis. This is the commonest mode of tonsillitis. This is the commonest mode of infection leading to "infection leading to "acute acute hematogenous osteomyelitishematogenous osteomyelitis""

22 . .Local spread of infection from a nearby Local spread of infection from a nearby focus of suppuration e.g dental abscess, focus of suppuration e.g dental abscess, suppurative otitis mediasuppurative otitis media

33 . .Direct infection of bone through a Direct infection of bone through a compound (open) fracturecompound (open) fracture

Bones affectedBones affected::

11 . .In acute In acute hematogenoushematogenous osteomyelitis, the osteomyelitis, the metaphyses of long bonesmetaphyses of long bones are the are the commonest site of affectioncommonest site of affection..

22 . .In In non-hematogenousnon-hematogenous osteomyelitis, osteomyelitis, any any bony sitebony site can be affected can be affected..

Pathology of acute hematogenous Pathology of acute hematogenous osteomyelitisosteomyelitis::

11 . .A localized suppurative inflammation (abscess) A localized suppurative inflammation (abscess) develops in the metaphysis from which infection develops in the metaphysis from which infection rapidly spreads to the bone marrow cavity and rapidly spreads to the bone marrow cavity and

along the Haversian canals to the periosteumalong the Haversian canals to the periosteum . .22 . .Infection of the periosteum is rapidly followed by Infection of the periosteum is rapidly followed by

accumulation of pus underneath the periosteum accumulation of pus underneath the periosteum i.e. formation of a i.e. formation of a subperiosteal abscesssubperiosteal abscess . .

33 . .Thrombosis then occurs in the penetrating Thrombosis then occurs in the penetrating arteries leading to ischemic necrosis of a variable arteries leading to ischemic necrosis of a variable portion of the bone which becomes gradually portion of the bone which becomes gradually separated from the surrounding viable bone by separated from the surrounding viable bone by osteoclastic activity. The necrotic bone is called osteoclastic activity. The necrotic bone is called

""sequestrumsequestrum ." ."

44 . .As the infection becomes less acute, new As the infection becomes less acute, new bone is formed by the irritated bone is formed by the irritated osteoblasts, particularly subperosteally. osteoblasts, particularly subperosteally. The subperiosteal new bone forms a shell The subperiosteal new bone forms a shell around the sequestrum, known as around the sequestrum, known as ""involucruminvolucrum". The involucrum is often ". The involucrum is often interrupted by irregular openings known interrupted by irregular openings known as "as "cloacaecloacae" through which pus is " through which pus is discharged and may dissect its way to discharged and may dissect its way to open through the skin by multiple open through the skin by multiple sinusessinuses..

N.B.N.B. Infection does not usually spread to Infection does not usually spread to nearby joints becausenearby joints because::

a) The epiphyseal cartilage provides a a) The epiphyseal cartilage provides a mechanical barrier against spread of mechanical barrier against spread of infection from the metaphysisinfection from the metaphysis..

b) The periosteum is firmly attached to the b) The periosteum is firmly attached to the margin of the epiphyseal cartilage margin of the epiphyseal cartilage preventing spread of infection from the preventing spread of infection from the subperiosteal abscesssubperiosteal abscess..

ComplcationsComplcations::

11 . .Acute toxemiaAcute toxemia

22 . .Septicemia which may lead to acute bacterial Septicemia which may lead to acute bacterial endocarditisendocarditis

33 . .Pyemia due to septic thrombophlebitisPyemia due to septic thrombophlebitis

44 . .Pathological fracturePathological fracture

55 . .ChronicityChronicity

66 . .Sympathetic effusion in nearby jointsSympathetic effusion in nearby joints

77 . .Suppurative arthritis due to local spread of Suppurative arthritis due to local spread of infection to joints where the metaphysis is partly infection to joints where the metaphysis is partly intra-articular e.g hip and shoulder jointsintra-articular e.g hip and shoulder joints

NONSPECIFIC CHRONIC OSTEOMYELYTISNONSPECIFIC CHRONIC OSTEOMYELYTIS::

This follows acute suppurative osteomyelitis and is This follows acute suppurative osteomyelitis and is characterized by thickened deformed bones with characterized by thickened deformed bones with cloacae and skin sinuses discharging puscloacae and skin sinuses discharging pus..

ComplicationsComplications::

11 . .Pathological fracturePathological fracture

22 . .Secondary amyloidosisSecondary amyloidosis

33 . .Squamous cell carcinoma developing in a skin Squamous cell carcinoma developing in a skin sinussinus

BRODIE'S ABSCESSBRODIE'S ABSCESS::

A localized chronic osteomyelitis that A localized chronic osteomyelitis that occurs most commonly in the occurs most commonly in the upper upper tibial metaphysistibial metaphysis. It appears as a . It appears as a small cavity filled with pus or serous small cavity filled with pus or serous fluid and surrouned by reactive fluid and surrouned by reactive sclerotic bonesclerotic bone..

TUBERCULOUS OSTEOMYELITISTUBERCULOUS OSTEOMYELITIS::

This is This is always secondaryalways secondary and usually results and usually results from from hematogenous disseminationhematogenous dissemination of of infection from a tuberculous focus in the infection from a tuberculous focus in the lungs, lymph nodes or urinary tractlungs, lymph nodes or urinary tract . .

The tuberculous reaction leads to caseation The tuberculous reaction leads to caseation and and bone destruction with only little or NO bone destruction with only little or NO new bone formationnew bone formation. Any bone can be . Any bone can be affected but the commonest sites are the affected but the commonest sites are the vertebraevertebrae..

Tuberculosis of the Spine (Pott's Tuberculosis of the Spine (Pott's Disease)Disease)::

This develops most commonly in the This develops most commonly in the lower dorsal lower dorsal (thoracic) and upper lumbar vertebrae(thoracic) and upper lumbar vertebrae. Infection . Infection usually starts in a usually starts in a single vertebral bodysingle vertebral body leading to caseation and bone destruction, then leading to caseation and bone destruction, then spreadsspreads : :

a) through the inter-vertebral discs to involve other a) through the inter-vertebral discs to involve other vertebral bodies, andvertebral bodies, and

b) to the nearby soft tissues leading to localized b) to the nearby soft tissues leading to localized accumulations of caseous material known as accumulations of caseous material known as cold abscessescold abscesses..

ComplicationsComplications::

11 . .Deformity of the spine due to vertebral collapse, in the form Deformity of the spine due to vertebral collapse, in the form of kyphosis, lordosis or scoliosisof kyphosis, lordosis or scoliosis

22 . .Paraplegia due to compression of the spinal cord by caseous Paraplegia due to compression of the spinal cord by caseous material and necrotic bone fragments derived from the material and necrotic bone fragments derived from the diseased vertebral bodiesdiseased vertebral bodies

33 . .Cold abscess inCold abscess in:: a) Retropharyngeal space or posterior triangle of the neck a) Retropharyngeal space or posterior triangle of the neck

(cervical vertebrae)(cervical vertebrae) b) Intercostal space along a rib (thoracic vertebrae)b) Intercostal space along a rib (thoracic vertebrae)

c) Psoas sheath (c) Psoas sheath (psoas abscesspsoas abscess), inguinal region or even ), inguinal region or even popleteal fossa (lumbar vertebrae)popleteal fossa (lumbar vertebrae)

44 . .Miliary tuberculosisMiliary tuberculosis

55 . .Secondary amyloidosisSecondary amyloidosis

Bone Tumors and Tumor-like Bone Tumors and Tumor-like ConditionsConditions

BONE FORMING TUMORSBONE FORMING TUMORS::

These includeThese include::

11 . .OsteomaOsteoma

22 . .Osteoid osteomaOsteoid osteoma

33 . .Benign osteoblastomaBenign osteoblastoma

. .44 . .OsteosarcomaOsteosarcoma

OsteomaOsteoma::

A benign tumor composed of woven or lamellar A benign tumor composed of woven or lamellar bonebone . .

It It develops most commonlydevelops most commonly in cranial and facial in cranial and facial bonesbones . .

It appears It appears grosslygrossly as a hemisphecal hard mass that as a hemisphecal hard mass that bulges underneath the periosteum or endosteum. bulges underneath the periosteum or endosteum. It is usually solitary but multiple osteomas occur It is usually solitary but multiple osteomas occur in Gardner's syndrome (an autosomal dominant in Gardner's syndrome (an autosomal dominant disorder characterized by multiple osteomas, disorder characterized by multiple osteomas, intestinal adenomatous polyps, epidermal cysts intestinal adenomatous polyps, epidermal cysts and fibromatosis)and fibromatosis)..

Osteosarcoma (osteogenic sarcoma)Osteosarcoma (osteogenic sarcoma)::

A malignant mesenchymal tumor in which A malignant mesenchymal tumor in which the neoplastic cells form osteoid or the neoplastic cells form osteoid or calcified bone matrixcalcified bone matrix . .

It is the It is the commonest primary malignant bone commonest primary malignant bone tumortumor . .

It occurs most commonly between the ages It occurs most commonly between the ages of of 10 and 25 years10 and 25 years, particularly in males. , particularly in males. Cases occurring Cases occurring after the age of 40 years after the age of 40 years are usually preceded by Paget's disease of are usually preceded by Paget's disease of bone or bone irradiationbone or bone irradiation..

Gross appearanceGross appearance::

The The commonest sitecommonest site of osteosarcoma is of osteosarcoma is metaphysis of long bones, metaphysis of long bones, particularlyparticularly around the knee jointaround the knee joint, although any bone , although any bone can be affectedcan be affected . .

It It appears grosslyappears grossly as a fusiform mass that as a fusiform mass that destroys and replaces the bone and often destroys and replaces the bone and often elevates and infiltrates the periosteum. It elevates and infiltrates the periosteum. It may also infiltrate the surrounding skeletal may also infiltrate the surrounding skeletal muscle. The consistency and color vary muscle. The consistency and color vary according to the microscopic (histologic) according to the microscopic (histologic) type of the tumortype of the tumor::

11 . .In the In the osteoblastic (osteosclerotic)osteoblastic (osteosclerotic) type type

in which the neoplastic cells form excessive bone in which the neoplastic cells form excessive bone matrix, the consistency is firm to hard and the matrix, the consistency is firm to hard and the color is grayishcolor is grayish . .

The neoplastic bone often forms spicules that run The neoplastic bone often forms spicules that run perpendicular to the long axis of the bone giving perpendicular to the long axis of the bone giving a characteristic a characteristic "sun ray appearance""sun ray appearance" in X-ray in X-ray filmsfilms . .

Another characteristic X-ray finding is the Another characteristic X-ray finding is the "Codman's triangle""Codman's triangle" resulting from the resulting from the deposition of reactive subperiosteal bone in the deposition of reactive subperiosteal bone in the angle between the bone and the elevated angle between the bone and the elevated periosteumperiosteum..

22 . .In the In the osteolyticosteolytic type type

in which there is only little or in which there is only little or practically no new bone formation, practically no new bone formation, the consistency is soft and the cut the consistency is soft and the cut surface is pinkish-grayi with areas of surface is pinkish-grayi with areas of necrosis and hemorrhagenecrosis and hemorrhage..

33 . .In the In the telangiectatictelangiectatic type type

which is highly vascular, the which is highly vascular, the consistency is soft and the color is consistency is soft and the color is purplish-redpurplish-red..

Microscopic appearanceMicroscopic appearance::

Osteosarcoma consists ofOsteosarcoma consists of::

11 . .Malignant osteoblastsMalignant osteoblasts which may be polygonal, which may be polygonal, spindly or multinucleated and show variable spindly or multinucleated and show variable nuclear pleomorphism and mitotic activity nuclear pleomorphism and mitotic activity depending on the grade of the tumordepending on the grade of the tumor

22 . .A stromaA stroma containing variable amounts of osteoid, containing variable amounts of osteoid, calcified bone matrix, cartilage, fibrous tissue calcified bone matrix, cartilage, fibrous tissue and blood vessels depending on the histologic and blood vessels depending on the histologic

type of the tumortype of the tumor

SpreadSpread::

11 . .Direct (local) spread to periosteum, Direct (local) spread to periosteum, surrounding muscles and marrow cavitysurrounding muscles and marrow cavity

22 . .Blood (hematogenous) spread to lungs Blood (hematogenous) spread to lungs and other organs. This occurs earlyand other organs. This occurs early

33 . .Lymphatic spread. This is rare and lateLymphatic spread. This is rare and late

CARTILAGE FORMING TUMORSCARTILAGE FORMING TUMORS::


11 . .Osteochondroma (exostosis)Osteochondroma (exostosis)

22 . .ChondromaChondroma

33 . .Benign chondroblastomaBenign chondroblastoma

44 . .Condromyxoid fibromaCondromyxoid fibroma

55 . .ChondrosarcomaChondrosarcoma

Osteochondroma (exostosis)Osteochondroma (exostosis)::

A benign A benign developmental tumor-like lesiondevelopmental tumor-like lesion consisting consisting of bone and hyaline cartilageof bone and hyaline cartilage . .

It It arises most commonlyarises most commonly from the from the metaphysis of metaphysis of long bones near the epiphyseal platelong bones near the epiphyseal plate

and appears and appears grosslygrossly as a bony mass covered by a as a bony mass covered by a cap of cartilage and attached to the bone by a cap of cartilage and attached to the bone by a pedicle. It is usually solitary but multiple pedicle. It is usually solitary but multiple exostosis are inherited as an autosomal dominant exostosis are inherited as an autosomal dominant disease. It may rarely undergo malignant disease. It may rarely undergo malignant transformation into a transformation into a chondosarcomachondosarcoma, , particularly when multipleparticularly when multiple..

ChondromaChondroma::

A benign tumor composed of hyaline A benign tumor composed of hyaline cartilagecartilage . .

It It occurs most commonlyoccurs most commonly in the in the short tubular short tubular bones of the hands and feetbones of the hands and feet..

It is usually solitary but multiple chondromas It is usually solitary but multiple chondromas occur in Ollier's disease. It may rarely occur in Ollier's disease. It may rarely undergo malignant transformation into a undergo malignant transformation into a chondrosarcomachondrosarcoma, particularly when , particularly when multiplemultiple..

ChondrosarcomaChondrosarcoma::

A malignant cartilaginous tumorA malignant cartilaginous tumor . .

It occurs most commonly in It occurs most commonly in adults adults between the ages of 30 and 60 between the ages of 30 and 60 yearsyears, particularly in males, particularly in males . .

It usually arises do novo but may It usually arises do novo but may rarely arise from a pre-existing rarely arise from a pre-existing exostosis or chondromaexostosis or chondroma..


The The commonest sitescommonest sites of chondrosarcoma are the of chondrosarcoma are the pelvic bones, ribs, shoulder girdle and proximal pelvic bones, ribs, shoulder girdle and proximal femur or humerusfemur or humerus . .

It It appears grossly asappears grossly as a firm to hard, lobulated, a firm to hard, lobulated, translucent, bluish-gray mass that destroys and translucent, bluish-gray mass that destroys and replaces the bone. replaces the bone. Focal calcificationFocal calcification is common is common and constitutes and important and constitutes and important radiological signradiological sign. . There may be also myxomatous degeneration There may be also myxomatous degeneration and necrosisand necrosis . .

The mass may be located within the medullary The mass may be located within the medullary cavity (cavity (central or intramedullary central or intramedullary chondrosarcomachondrosarcoma) or on the surface of the bone ) or on the surface of the bone ((peripheral or juxtacortical chondosarcomaperipheral or juxtacortical chondosarcoma))..


Chondrosarcoma consists of Chondrosarcoma consists of malignant cartilagemalignant cartilage cells and cells and a a cartilaginous matrixcartilaginous matrix . .

Low gradeLow grade chondrosarcomaschondrosarcomas may be so well diffrentiated may be so well diffrentiated and, hence, difficult to distinguish from benign and, hence, difficult to distinguish from benign chondromas. In such cases, chondromas. In such cases, clinical and radiological clinical and radiological features may be more important for differentiationfeatures may be more important for differentiation than than

microscopic examinationmicroscopic examination . .

High grade chondrosarcomasHigh grade chondrosarcomas, on the other hand, show , on the other hand, show marked nuclear pleomorphism, multinucleate tumor giant marked nuclear pleomorphism, multinucleate tumor giant cells and frequent mitosis and may be difficult to cells and frequent mitosis and may be difficult to differentiate from other high grade sarcomas. differentiate from other high grade sarcomas. Immunohistochemistry may help in such casesImmunohistochemistry may help in such cases..

SpreadSpread::

11 . .Local to surrounding tissueLocal to surrounding tissue..

22 . .Blood spread to lungs and other Blood spread to lungs and other organs, mainly in high grade tumorsorgans, mainly in high grade tumors

FIBROUS AND FIBRO-OSSEOUS FIBROUS AND FIBRO-OSSEOUS TUMORSTUMORS::


11 . .Fibrous cortical defect and non-ossifying Fibrous cortical defect and non-ossifying fibroma fibroma

22 . .Fibrous dysplasiaFibrous dysplasia

33 . .FibrosarcomaFibrosarcoma

44 . .Malignant fibrous histiocytomaMalignant fibrous histiocytoma

Fibrous dysplasiaFibrous dysplasia::

A benign A benign tumor-like lesiontumor-like lesion of of unknown etiologyunknown etiology that that may involve a single bone (monostotic type) or may involve a single bone (monostotic type) or multiple bones (polyostotic type)multiple bones (polyostotic type) . .

It occurs It occurs most commonly in childrenmost commonly in children and usually and usually affects the ribs, jaw, femur and tibiaaffects the ribs, jaw, femur and tibia . .

MicroscopicallyMicroscopically, it consists of fibrous tissue , it consists of fibrous tissue interspersed by interspersed by thin, branching or curvedthin, branching or curved trabeculae of trabeculae of woven bonewoven bone that that lack osteoblasticlack osteoblastic rimmingrimming. It may rarely change to a malignant . It may rarely change to a malignant fibrous histiocytomafibrous histiocytoma..

MISCELLANEOUS TUMORSMISCELLANEOUS TUMORS::


11 . .Ewing’s sarcomaEwing’s sarcoma

22 . .OsteoclastomaOsteoclastoma

33 . .Multiple myelomaMultiple myeloma

44 . .Non-Hodgkin’s lymphomaNon-Hodgkin’s lymphoma

Ewing' s sarcomaEwing' s sarcoma::

A A highly malignanthighly malignant tumor of tumor of neuroectodermalneuroectodermal originorigin . .

Virtually all of these tumors have a reciprocal Virtually all of these tumors have a reciprocal translocation between chromosomes 11 and 22 translocation between chromosomes 11 and 22

[t(11;22)][t(11;22)]..

It occurs most commonly between the ages of It occurs most commonly between the ages of 10 10 and 25 yearsand 25 years

and usually affects the and usually affects the diaphyses of long bonesdiaphyses of long bones..


A soft grayish mass that infiltrates and A soft grayish mass that infiltrates and replaces the bone, surrounded by replaces the bone, surrounded by parallel layers of reactive parallel layers of reactive subperiosteal bone that gives a subperiosteal bone that gives a characteristic characteristic "onion skin""onion skin" appearance in X-ray filmsappearance in X-ray films..


Sheets of uniform small round cells Sheets of uniform small round cells with hyperchromatic nuclei and with hyperchromatic nuclei and scanty cytoplasm containing scanty cytoplasm containing glycogenglycogen..

Clinical featuresClinical features::

Bone swelling and pain, sometimes Bone swelling and pain, sometimes accompanied by fever, leucocytosis accompanied by fever, leucocytosis and increased ESR, a picture that and increased ESR, a picture that may resemble osteomyelitismay resemble osteomyelitis..

SpreadSpread::

11 . .Local to surrounding tissuesLocal to surrounding tissues

22 . .Hematogenous to lung and other Hematogenous to lung and other organs including organs including other bonesother bones

Osteoclastoma (Giant Cell Tumor of Osteoclastoma (Giant Cell Tumor of Bone)Bone)::

A bone tumor characterized by presence of A bone tumor characterized by presence of numerous osteoclastic giant cellsnumerous osteoclastic giant cells

Its origin is not settled but it probably Its origin is not settled but it probably arisesarises from the fibroblast or monocytefrom the fibroblast or monocyte rather rather than the osteoclastthan the osteoclast

It occurs most commonly between It occurs most commonly between 20-4020-40 yearsyears of age of age


The commonest The commonest sitessites are the are the epipyhses ofepipyhses of long boneslong bones, particularly the lower end of , particularly the lower end of the femur, the upper end of the tibia, the the femur, the upper end of the tibia, the upper end of the humerus and the lower upper end of the humerus and the lower end of the radiusend of the radius

It It appears grosslyappears grossly as a soft grayish mass as a soft grayish mass that replaces & expands the epiphysisthat replaces & expands the epiphysis,,surrounded by a thin shell of cortical bone surrounded by a thin shell of cortical bone that gives a sensation of that gives a sensation of egg-shell egg-shell crackling crackling on palpationon palpation

X-ray AppearanceX-ray Appearance::

A characteristic “A characteristic “soap bubblesoap bubble” ” appearance due to persistence ofappearance due to persistence of variable amounts of thin bone variable amounts of thin bone trabeculae within the tumortrabeculae within the tumor


Consists ofConsists of

11 . .Numerous Numerous osteoclastsosteoclasts appearing as appearing as large cells with many nucleilarge cells with many nuclei

22 . .Plump, Plump, oval or spindly cellsoval or spindly cells

BehaviorBehavior::

11 . .Most cases are benign (grade I tumors)Most cases are benign (grade I tumors)

22 . .Some cases are locally malignant and frequently Some cases are locally malignant and frequently recur after removal (grade II)recur after removal (grade II)

33 . .Rare cases are frankly malignant and may Rare cases are frankly malignant and may metastasize to the lungs. These show metastasize to the lungs. These show nuclear nuclear pleomorphismpleomorphism and and frequent mitosisfrequent mitosis in the in the oval/spindly cells and a oval/spindly cells and a decreased number of decreased number of osteoclastsosteoclasts (grade III) (grade III)

METASTATIC TUMORSMETASTATIC TUMORS::

Commoner than primary tumorsCommoner than primary tumors and occur most commonly in and occur most commonly in sites sites rich in red bone marrowrich in red bone marrow e.g. e.g. vertebrae, ribs and proximal vertebrae, ribs and proximal humerus and femurhumerus and femur..

Results most commonly fromResults most commonly from hematogenous dissemination ofhematogenous dissemination of::

11 . .Carcinomas, particularly thyroid, breast, Carcinomas, particularly thyroid, breast, lung, stomach, kidney, suprarenal and lung, stomach, kidney, suprarenal and prostatic carcinomasprostatic carcinomas

22 . .Various sarcomasVarious sarcomas

33 . .Childhood tumors e.g. neuroblastoma, Childhood tumors e.g. neuroblastoma, Wilms’ tumor, rhabdomyosarcoma and Wilms’ tumor, rhabdomyosarcoma and

Ewing’s sarcomaEwing’s sarcoma

44 . .Choriocarcinoma and malignant Choriocarcinoma and malignant melanomamelanoma

EffectsEffects::

11 . .Bone destruction leading to Bone destruction leading to bone painsbone pains and tendernessand tenderness, , pathological fracture pathological fracture andand hypercalcemia hypercalcemia

22 . .Reactive new bone formation: This is Reactive new bone formation: This is rarerare and is typically seen in and is typically seen in metastatic metastatic carcinoma of the prostatecarcinoma of the prostate

33 . .Anemia due to bone marrow replacementAnemia due to bone marrow replacement