Osteoblastic metastasis commonly arise from:

Ans. b. Prostate (Ref: Harrison 19/e p119e-4, 18/e p820-821; Devita 9/e p2512-2513; CSDT 12/e p1202)Osteoblastic metastasis commonly arises from carcinoma prostate.MC site of primary for bone metastasis: CA ProstateQMC cause of osteoblastic secondaries in males: CA ProstateQMC cause of osteoblastic secondaries in females: CA BreastQMC tumor metastasize to bone in females: CA BreastQBone MetastasisMetastatic tumors of bone are more common than primary bone tumorsQ.Tumors usually spread to bone hematogenously, axial skeleton is seeded more than appendicular skeleton partly due to persistence of red marrowQ.In order of decreasing frequency, the sites most often involved are vertebrae (most commonQ >proximal femur >pelvis >ribs >sternum >proximal humerus >skull.Extremities distal to elbow and knee are least commonly involved sitesQ, but if distal extremity is involved there is high probability of myelomaQ.Metastasis to small bones originate from: Lung, kidney or colonQBone is a common site of metastasis for carcinoma of the prostate, breast, lung, kidney, bladder, thyroid, lymphomas and sarcomasQ.Bateson's vertebral plexus allow cells to enter the vertebral circulation without first passing through the lungs and is responsible for high rate of prostate cancer metastasis to boneQ.Diagnosis:Bone scan is investigation of choice for bone metastasisQ.Purely osteolytic lesions are best detected by plain radiography, but they are not apparent until they are >1 cm and have destroyed 30-50% of boneQ.These are associated with hypercalcemia and with the excretion of hydroxyproline containing peptidesQ.Treatment:Treatment options: Bisphosphonates, corticosteroids, radiotherapy (EBRT) and radionucleotides.EBRT is given in symptomatic bony metastasQ.Samarium-153 is a beta emitter, very effective in relieving pain of bone metastasisQ.Bone MetastasisPurely osteolyticMostly osteolyticMostly osteoblasticPurely osteoblastic* Kidney (expansile)Q* Thyroid* Lung* GI tumors* BreastQ* Seminoma* Carcinoid* Neurogenic tumors* Uterus and ovary* Urinary bladder* ProstateQ