COMMON BONE TUMORSBENIGN BONE TUMORS

CLASSIFICATION : 1.CHONDROID TUMORS

2.OSTEOID TUMORS 3.CYSTS

4.FIBROUS TUMORS 5.VASCULAR TUMORS

1.CHONDROID TUMORS:

A. OSTEOCHONDROMA B. ENCHONDROMA C.CHONDROBLASTOMA

A. OSTEOCHONDROMA

MOST COMMON SOLITARY BENIGN BONE TUMOROCCURS IN THE DISTAL FEMUR, PROXIMAL HUMERUS, PROXIMALTIBIA OF LONG BONES AND ILIUM AND SCAPULA OF FLAT BONES

ARISES FROM THE CORTEX OF BONE CONTINUOUS WITH CORTEXPEDUNCULTED OR SESSILE MEDULLA GROWS INTO THE OUTGROWING TUMOR

CHARACTERISTIC FEATURE IS AN ACTIVELY GROWINGCARTILAGE CAP SEEN WELL WITH USG, CT AND MRI BUT NOTWITH PLAIN XRAYWITH AGE CAP BECOMES CALCIFIED IN A PUNCTATE ORNODULAR FASHION

MRI T2W IMAGE SHOWS HYPERINTENSE CAP SURROUNDED BYHYPOINTENSE MUSCLE. MULTIPLE OSTEOCHONDROMA / DIAPHYSEAL ACASIS IS A RARECONDITION

IMPORTANT D/D IS CHONDROSARCOMA WHICH SHOWSCHARACTERISTICS OF MALIGNANT TUMOR

ENCHONDROMA

SECOND MOST COMMON BENIGN CARTILAGE LESION

BENIGN INTRAMEDULLARY NEOPLASM MADE UP OF LOBULES OFHYALINE CARTILAGE

MOST COMMONLY AFFECTS THE METAPHYSES OR DIAPHYSES OFTUBULAR BONES OF HANDS AND FEET- 40 – 65 %

PROXIMAL PHALANGE > METACARPAL > MIDDLE PHALANX

FEMUR, TIBIA,HUMERUS – 25%

RADIOLOGICAL FEATURES :

ECCENTRICALLY LOCATED METAPHYSIAL OR DIAPHYSEAL MASS

SOLITARY MASS , LYTIC LESIONS

WELL CIRCUMSCRIBED LOBULATED OR SMOOTH WALLED

MAY EXPAND THE CORTEX

CHONDRAL TYPE CALCIFICATION

ENCHONDROMA PROTUBERANCE – ECCENTRIC MASS ARISINGFROM SLENDER BONES SUCH AS RIBS OR FIBULA

MRI – T1W – INTERMEDIATE SIGNAL INTENSITY T2W – HIGH SIGNAL INTENSITY

CALCIFICATION OCCURS AS AREAS OF SIGNAL VOID SEPTATIONS IF PRESENT OCCUR AS SIGNAL VOID

LESS COMMON VARIETIES : PERIOSTEAL ENCHONDROMAMULTIPLE ENCHONDROMA(OLLIER'S DISEASE) AND MUFFUCISYNDROME (ENCHONDROMATOIS + HEMANGIOMA)

CHONDROBLASTOMA

EPIPHYSEAL TUMOR OCCURS BETWEEN 5 & 25 YEARS , RARE AFTER 30 YRSMOST COMMON SITE – PROXIMAL FEMUR AND AROUND KNEEJOINT FEET- CALCANEOUS AND TALUS MOST COMMONLY INVOLVED

STARTS IN EPIPHYSES BUT AS THE PLATES CLOSE EXTENDS INTOTHE METAPHYSES

RADIOLOGICAL FEATURES

SPHERICAL , LOBULAR LESION WITH THIN SCLEROTIC MARGIN

LINEAR PERIOSTEAL REACTION IS PRESENTASSOCIATED WITH ANEURYSMAL BONE CYST IN 15% CASES

MRI – VARIABLE SIGNAL INTENSITY ON T2W IMAGES, INCLUDINGHYPOINTENSITY AND FLUID LEVELS

THIS IS INVARIABLY SURROUNDED BY EDEMA AND JOINTEFFUSION WHICH APPEAR WITH HIGH SIGNAL INTENSITY

OSTEOID BONE TUMORA. ENOSTOSISB. OSTEOMA

C.OSTEOID OSTEOMA

A. ENOSTOSIS (BONE ISLAND)

FOCUS OF CORTICAL BONE LOCATED WITHIN THE MEDULLAINCIDENTAL FINDINGS MOST COMMONLY SEEN IN FEMUR ANDOTHER LONG BONES

MULTIPLE BONE ISLANDS ARE SEEN IN OSTEOPOIKILOSIS ANDOSTEOPTHIA STRIATA

RADIOLOGICAL FEATURES :DENSE SCLEROTIC FOCUS WITH CHARACTERISTIC SPICULATEDMARGINS WHICH BLENDS WITH THE TRABECULAE OF HOSTBONES

MRI – LOW SIGNAL INTENSITY AS THAT OF NORMAL CORTICALBONES

BONE SCINTIGRAPHY – LOW UPTAKE AND THUS DIFFERS FROMMETASTATIC SECONDARIES

OSTEOMA

C ONSISTS OF CORTICAL OR CANCELLOUS BONES

CORTICAL OSTEOMA – COMMON , AKA IVORY OSTEOMAMOST COMMONLY ARISES FROM PARANASAL SINUSES.LONG BONES AND SPINES ARE ALSO INVOLVED

RADIOLOGICAL FEATURES : DENSE HOMOGENOUS LESIONS WITHSMOOTH OR LOBULTED MARGINS

MULTIPLE CORTICAL OSTEOMAS ARE FOUND IN GARDNER'SSYNDROME

CANCELLOUS OSTEOMAS ARE RARE

OSTEOID OSTEOMA

ESSENTIALLY A HAMARTOMA

CHARACTERIC CLINICAL PICTURE : NIGHT PAIN RLIEVED BYASPIRIN

MIMICS NEROLOGICAL LESION WITH SLUGGISH REFLEXES ,OSTEOPOROSIS AND MUSCLE WASTING

AFFECTS ALL SKELETAL SITES LIKE CORTEX ,MEDULLA ANDSUBPERIOSTEAL REGION

DIAPHYSIS AND METAPHYSIS OF FEMUR AND TIBIA – 50% OFCASESIN SPINE – NEURAL ARCHINVOLVEMENT 90% OF TIME

RADIOLOGICAL FEATURES:

PLAIN FILM: CHARACTERISTIC FEATURE NIDUS WHICH MAY BELYTIC, SCLEROTIC, OR MIXED DENSITY

NIDUS – USUALLY MEASURES 5MM OR LESS, BUT MAY GROW UPTO15MM.NIDUS IS SURROUNDED BY MEDULLARY SCLEROSIS AND

PERIOSTEAL REACTION REACTIVE CHANGES MAY OBSCURE THE NIDUS IN PLAIN FILM

BONE SCINTIGRAPHY : DOUBLE DENSITY SIGN,AN AREA OFINTENSE ACTIVITY SURROUNDED BY AREA OF LESS INTENSEACTIVITY

CT : NEED 2-3 MM SLICES TO IDENTIFY NIDUSSHOWS MEDULLARY SCLEROSIS AND PERIOSTEAL REACTIONPERIOSTEAL REACTION ABSENT WITH INTRA ARTICULAR LESION ,LESIONS IN THE TERMINAL PHALANGES AND THOSE DEEP INMEDULLARY BONE AND MEDULLARY OR AT TENDINOUS ORLIGAMENTOUS INSERTIONS

MRI – CANNOT DEMOSTRATE NIDUS AND GIVES A CONFUSINGPICTURE

CYSTIC BENIGN TUMORSA. SIMPLE BONE CYSTS

B. ANEURYSMAL BONE CYST C. GIANT CELL TUMOR

A.SIMPLE BONE CYST AKA UNICAMERAL BONE CYST SOLITARY BUT NOT ALWAYS UNILOCULAR AGES GR : 5- 15 YRSMOST COMMON LOCATION :PROXIMALHUMERUS(60%) FOLLOWED BY PROXIMALFEMUR (30%)INITIALLY LOCATED IN THE PROXIMAL METAPHYSESTHEN PROGRESSES INTO DIAPHYSES WITH SKELETALGROWTH AND THEN THEY REACH THE MIDDLE ANDDISTAL THRD OF THE SHAFT

RADIOLOGICAL FEATURES PLAIN FILMSBC COMMONLY LOCATED CENTRALLY IN THE SHAFT EXPANSILE THINNING THE CORTEXTHE LESION IS TYPICALLY 6 – 8 CM IN SIZETRABECULATION IS COMMON PERIOSTEAL REACTION NOT SEENFRACTURE RESULTS IN FALLING FRAGMENT SIGN ANDPERIOSTEAL REACTION

MRI FEATURES :T1W – LOW TO INTERMEDIATE INTENSITYT2W OR STIR – HYPERINTENSITYFRACTURES RESULT IN HEMORRHAGE AND FLUID FLUIDLEVELS AND OEDEMA

ANEURYSMAL BONE CYST TRUE NEOPLASMAGE – 1ST AND 2ND DECADELONG BONES – 50 % SPINE – 20%FLAT BONES – MOST COMMON IN PELVIS SPINAL LESIONS CAN CAUSE SCOLIOSIS AND PARAPARESIS

RADIOLOGICAL FEATURES

PURELY LYTICEXPANSILE INTRAMEDULLARYARISING FROM THE METAPHYSIS OF LONG BONESEXTENDS TO THE GROWTH PLATE

MORE COMMONLY LOCATED ECCENTRICALLY BUT MAYBE CENTRALSPINAL LESIONS ARISE IN NEURAL ARCH WITHUNILATERAL COLLAPSE AND STRUCTURAL SCOLIOSIS

CT : OTHER THAN THOSE MENTIONED ABOVE CT SHOWSFINE SEPTAL OSSIFICATION , FLUID LEVELS, THIN RIM ANDINTERNAL SEPTAMRI : MEDULLARY EDEMA , FLUID LEVELS , THIN RIM ANDINTERNAL SEPTA, WHICH MAY ENHANCE FOLLOWINGGADOLINIUMMOST COMMON D/D IS TELANGIECTATIC OSTEOSARCOMA

GIANT CELL TUMORAGGRESSIVE BENIGN NEOPLASM MALIGNANT CHANGE OCCURSBENIGN LESIONS MAY UNDERGO METASTASIS

AGE -18 TO 44 YEARS OF AGELOCATION : SUBARTICULAR OR SUBCORTICALMOST COMMON SITES : KNEE , DISTAL RADIUS ANDPROXIMAL HUMERUS BEING COMMONEST SITESSACRUM MOST COMMONLY AFFECTED SITE IN SPINE ANDVERTEBRAL BODY IS AFFECTED WITH VERTEBRALINVOLVEMENT

RADIOLOGICAL FEATURECLASSICALLY SUBARTICULARECCENTRIC LYTICGEOGRAPHIC , NON SCLEROTIC MARGINSAGGRESSIVE LESIONS – POORLY DEFINES MARGINSTRABECULATION AND CORTICAL EXPANSION COMMONFEATURESCORTICAL DESTRUCTION WITH EXTRA OSSEUSEXTENSION MAY OCCUR IN UPTO 50% OF CASESPERIOSTEAL REACTION PRESENT IN CASES WITHFRACTURES

MRI – ISO /HYPO INTENSE SIGNAL HYPERINTENSE SIGNAL WITH HEMORRAHGE / BLOOD

HYPOINTENSE SIGNAL T2W IMAGES DUE TO HEMOSIDERINDEPOSITION DUE TO CHRONIC HEMORRHAGE

FLUID-FLUID LEVELS INDICATE SECONDARY ABC CHANGE

COMMON D/D : LYTIC OSTEOSARCOMA , LYTICMETASTASIS FROM PRIMARY RENAL TUMORS

FIBROUS BENIGN BONE TUMORSA. NON OSSIFYING FIBROMA

B. FIBROUS CORTICAL DEFECTC.FIBROUS DYSPLASIA

A.NON OSSIFYING FIBROMA

BENIGN NEOPLASMAGE – 2ND DECADELOWER LIMB INVOLVEMENT – 90% AT TIBIA AND DISTALEND OF FEMURMULTIPLE LESIONS FAMILIAL AND ASSOCIATED WITHNEUROFIBROMATOSISUSUALLY DIAGNOSED RADIOLOGICALLY

RADIOLOGICAL FEATURES :

PLAIN FILM – DIAGNOSTIC

LESIONS METAPHYSEAL , DIAMETAPHYSEAL ESSENTAILLY CORTICALLOBULATED SOAP BUBBLE APPEARANCE ENLARGING INTO MEDULLA IS CLASSICALTUMOR OVAL IN SHAPE WITH LONG AXIS IN THE LINE OFTHE BONEPERIOSTEAL REACTION SEEN ONLY AFTER FRACTURE

MRI : T1W – INTERMEDIATE SI , T2W – HYPOINTENSE 80%

B.FIBROUS DYSPLASIA

DEVELOPMENTAL DISORDER OF BONE MONOSTOTIC AND POLYOSTOTIC TYPE

RADIOLOGICAL FEATURE

GEOGRAPHIC LESION WITH BONE EXPANSION ANDDEFORMITYDIFFUSE GROUND GLASS MATRIX MINERALIZATIONPRESENTPERIOSTEAL RECTION NOT PRESENT WITHOUT FRACTURE

VARUS DEFORMITY OF PROXIMAL FEMUR CALLEDSHEPHERD'S CROOK APPEARANCE IS A LATE FINDING

SYNTIGRAPHY – BEST FOR IDENTIFYING MUTIPLE LESION

MRI T1W – HYPOINTENSE, HEMORRHAGE – MILDHYPERINTENSITY.

T2W – HYPO/HYPERINTENSEINTERNAL SEPTATIONS WITH CYSTIC CHANGE AND FLUIDLEVELS ARE SEEN IV CONTRAST PRODUCES – SEPTAL ENHANCEMENT

PRESENCE OF CHONDROID CALCIFICATION INDICATESFIBROCARTILAGENOUS DYSPLASIA

C. FIBROUS CORTICAL DEFECTCOMMON IN CHILDHOOD

NORMAL VARIENTCOMMONLY SEEN IN DISTAL FEMORAL AND PROXIMALTIBIAL METAPHYSESRADIOLOGICALLY SAME AS NON OSSIFYING FIBROMADIFFERING ONLY IN SIZE MEASURING ABOUT 1- 1.5 CM INMAXIMAL DIMENSION

VASCULAR TUMORSHEMANGIOMA

TYPES : CAPILLARY , CAVERNOUS ,ARTERIOVENOUS ORVENOUSOSSEOUS CAPILLARY HEMANGIOMA AFFECT VERTEBRALBODY OSSEOUS CAVERNOUS HEMANGIOMA AFFECTS SKULLVAULT

RADIOLOGICAL FEATURES:PLAIN FILM – VERTEBRAL BODIES- COARSE VERTICALTRABECULATIONS DUE TO HYPRTROPHY OF PRIMARYTRABECULAEAND DESTRUCTION OF SECONDARY TRABECULAE

LONG BONES: STRIATED LESIONS ARE FOUND INEPIPHYSES AND METAPHYSES WITH THE DIRECTION OFTHE STRIATIONS ALONG THE LONG AXIS OF THE BONE.

CT : DENSE DOTS (THICKENED TRABECULATIONS) WITH INFATTY MATRIX

MRI – INCREASED SIGNAL INTENSITY ON T1W AND T2WIMAGES

VASCULAR HEMANGIOMAS – CT CAN SHOW THICKENEDTRABECULAE AND MRI SHOWS REDUCED SIGNALINTENSITY ON T1W IMAGES

FLAT BONES: MULTIPLE , WELL DEFINED LYTIC LESIONSPRODUCE A SOAP BUBBLE EFFECT

SKULL – SUN BURST APPEARANCE CAN BE SEEN