Fallen fragment sign is seen in
(A) Simple bone cyst[?]Fallen Fragment Sign:Small piece of bone settles to dependent portion of a Unicameral Bone Cyst from pathological fracture.Solitary Bone Cyst:Physical findings - Usually asymptomatic.Cyst lying adjacent to growth plate can lead to growth disturbances.X ray findings centrally located, lytic lesion:Expansion of the bone.Well marginated outline.Thinning of the cortex (scalloping)Pathognomonic for a simple (unicameral) bone cyst following a pathological fracture.Fallen fragment sign:Periosteal surface is smooth.Loculated appearance is due to presence of ridges over inner surface of cyst.May be seen in other cystic lesions, e.g. eosinophilic granuloma.RADIOLOGICAL DIAGNOSTIC SIGNSHatchet signRecurrent anterior dislocation of shoulderMetacarpal sign (presence of short 4th metacarpal)Turner's syndrome, Pseudohypoparathyroidism & some Normal peopleSnow cap signSickle cell diseaseTrummerfeld sign seen inScurvy, Leukaemia & Acute infection (Congenital syphilis)Corner sign of Park & Pelkan signScurvyVacuum sign is seen inPerthes' disease & Degen. disease of spineWaldenstrom's sign is seen inEarly Perthes' dis. & in Irritable Hip syndromeHalo sign of WimburgerCongenital Syphilis, ScurvyTram-track signAnkylosing spondylitisWimbergeris signCongenital syphilisFallen fragment signUnicameral bone cystBeheaded Scottish terrier signSpondylolisthesisOther OptionsOsteosarcoma:Most common malignant primary bone tumor in young adults + children; 2nd MC prirnary malignant bone tumor after multiple myeloma.Neoplastic tissue is radiolucent, Periosteal reaction shows 'Codman's triangle', Zone of transformation is fairly large, "sun-ray" appearance is characteristic (produced by thin radiopaque spicules of bone, radiating away from the cortex of the bone), large soft tissue swellingParosteal Sarcoma - Low grade malignancy, seen in older age group, bone forming tumour, shows osteolytic lesion with radiolucent line between the cortex & bone & the new bone forms in the soft tissue around it.Adamantinoma = (Malignant) Angioblastoma = locally aggressive/malignant lesion.Histo: pseudoepithelial cell masses with peripheral columnar cells in a palisade pattern with varying amounts of fibrous stroma; areas of squamous/tubular/alveolar/vessel transformation; prominent vascularity; resembles ameloblastoma of the jaw.Location: middle 1/3 of tibia (90%), fibula, ulna, carpals, metacarpals, humerus, shaft of femur eccentric round osteolytic lesion with sclerotic margin, may have additional foci in continuity with major lesion (Characteristic) may show mottled density bone expansion frequent often multiple.Prognosis: tendency to recur after local excision; after several recurrences pulmonary metastases may develop.Aneurysmal bone cyst = expansile pathologically benign lytic lesion of bone containing thin-walled cystic cavities filled with chronic blood products; name derived from roentgen appearance purely lytic eccentric radiolucency.Location: (a) spine (12-30%) with slight predilection for posterior elements; thoracic > lumbar > cervical spine (22%); involvement of vertebral body (40-90%); may involve two contiguous vertebrae (25%).(b) long bones; eccentric in metaphysis of femur, tibia, humerus, fibula; pelvis aggressive expansile ballooning lesion of "soap-bubble" pattern + thin internal trabeculations rapid progression within 6 weeks to 3 months.Sclerotic inner portion almost invisible thin cortex (CT shows integrity) tumor respects epiphyseal plate no periosteal reaction (except when fractured).
Simple bone cyst
Osteosarcoma
Adamantinoma
Aneurysmal bone cyst
Skeletal System