B i.e. Multiple Myeloma Old age, male sex & veebral involvement (lytic lesion) indicate towards diagnosis of Metastasis & Multiple myeloma. But Absence of primary and characterestic multiple punched out lesions on X-Ray skull is diagnostic of Multiple myelomaQ. Osteomalacia: - Looser's zoned or PseudofractureQ (Hallmark) Mnemonic - "Losse Pencilin Fish" - Pencilling-in- of veebral bodies - Cod - fish (marked biconvex) veebraeQ Hyper parathyroidism : - Brown tumorQ Mnemonic - - Sub periosteal ErosionQ "Brown Erosed Salt Basket" - Salt & Pepper or Pepper - Pot skullQ - Basket work appearanceQ of coex Renal Osteodystrophy(d/t CRF): - It combines findings of ostemalacia, hyperparathyroidism and bone sclerosis - Osteomalacia lit Looser's zone - Hyper PTH 1/t Subperiosteal Erosion of bone - Osteosclerosis Vt Rugger Jersey spineQ (End plate sclerosis with alternating bands of radiolucency) In children with CRF, the combination of rickets & hyperparathyroidism leads to Rotting Fence Post appearance.Q Multiple Myeloma: Two cardinal features are: Generalized reduction of bone density (Osteopenia) Localized areas of radiolucency (Punched outQ/Rain drop lesionsQ) in red marrow areas i.e. axial skeletal - spine & skull. In multiple Myeloma lytic lesions of spine are usually associated with some collapse & soft tissue extension i.e. paraveebral soft tissue shadows (differentiation from Metastasis). Differentiation from inflamatory lesions can be made as the interveebral disc space & aicular surfaces are not affected.