<prompt> X ray of skull showing multiple lesions. The diagnosis is?Pagets diseaseMultiple myelomaEosinophilic granulomaOsteomyelitis  <response>: B Multiple myeloma?MULTIPLE MYELOMA:Most common primary malignant neoplasm in adults.Disseminated form - scattered, axial skeleton predominant site; vertebrae 50, distribution correlates with normal sites of red marrow.Solitary form - vertebrae pelvis skull sternum ribs.Spinal Plasma Cell Myeloma - sparing of posterior elements, paraspinal soft-tissue mass with extradural extension, scalloping of anterior margin of vertebral bodies.Generalized osteoporosis with accentuation of trabecular pattern.Punched out appearance of widespread osteolytic areas with endosteal scalloping uniform size, Diffuse osteolysis, Expansile osteolytic lesions in ribs, pelvis, long bones, Soft-tissue mass adjacent to bone destruction.Sclerosis may occur after chemotherapy, radiotherapy, fluoride administration.Sclerotic form of multiple myeloma is associated with Polyneuropathy,Organomegaly, Endocrine abnormalities, M-protein, Skin changes.Other Options?Pagets disease Osteitis Deformans:Multiple chronic skeletal disease due to paramyxoviral infection causes resorption and bone formation.The newly formed bone is abnormally soft with disorganized trabecular pattern mosaic pattern causing deformity.-Active phase: Osteolytic phase aggressive bone resorption with lytic lesions.-Inactive phase: Quiescent phase bone turnover with skeletal sclerosis.-Mixed pattern is common lytic sclerotic phases coexist.Skull - Inner outer table thickening Skull becomes larger Soldiers helmet, diploic widening, osteoporosis circumscripta, cotton wool appearance, sclerosis of base of skull, Facial bones are usually not affectedLong bones - Candle flame or Blade of grass lysis results fracturePelvis - protrusio acetabulae, thickened trabeculaeSpine - Upper cervical, low dorsal, midlumbar vertebral involvement, picture frame vertebra bone-within-bone, ivory vertebra, ossification of spinal ligaments, paravertebral soft tissue, disk spaces. Bone scan - Increased uptake.?Eosinophilic granuloma most benign variety of LCH localized to bone.Location: bone in children or lung in adultsSites: Mostly diaphyseal; epiphyseal lesions are uncommon; Expansile lytic lesion with ill-defined sclerotic edges; Endosteal scalloping, widening of medullary cavity; Cortical thinning, intracortical tunneling; Erosion of cortex soft-tissue mass; Laminated periosteal reaction frequent, may show interruptions; May appear rapidly within 3 weeks; Lesions respect joint space growth plate.Prognosis: Excellent with spontaneous resolution of bone lesions in 6-18 months.?Osteomyelitis:Acute Osteomyelitis: Initial X-rays often normal as long as 10 days, localized soft-tissue swelling, area of bone destruction lags 7-14 days behind pathologic changes-Involucrum new bone formation, periosteal reaction develops after 20 days, sequestrum detached dead bone appears dense radiologically, cloaca formation.-Chronic Osteomyelitis: Thick irregular sclerotic bone with radiolu- cencies, elevated psriosteum, chronic draining sinus.-Sclerosing Osteomyelitis of Garre -- Focal bulge of thickened cortex sclerosing periosteal reactionBrodie Abscess: Subacute pyogenic osteomyelitis smouldering indolent infection, Central area of lucency surrounded by dense rim of reactive sclerosis.BONE SCANS local in radiopharmaceutical uptake positive within 24-72 hoursGa-67 scans - 100 sensitivity; increased uptake 1 day earlier than for Tc-99m MDP Gallium helpful for chronic osteomyelitisStatic Tc-99m diphosphonate - 83 sensitivityThree-phase skeletal scintigraphy - 92 sensitivity, 87 specificityPhase: 1: Radionuclide angiography profusion phase of regional blood flow; 2: blood pool images; 3: bone uptakeWBC-scan--In-111-labeled leukocytes - best agent for acute infections--Tc-99m labeled leukocytes - preferred over in 111-leukocyte imaging especially in extremities.--WBC scans have largely replaced gallium imaging for acute osteomyelitis. 