A 50-year-old man suffering from carcinoma of prostate showed areas of sclerosis and collapse of T10 and Til vertebrae in X-ray. The spread of this cancer to the above vertebrae was most probably through:: (A) Sacral canal, (B) Lymphatic vessels, (C) Internal vertebral plexus of veins, (D) Superior rectal veins
Answer is C. Ans. is 'c' i.e. internal vertebral plexus of veins Prostatic cancer spreads to the bones through blood vessels; first into the periprostatic venous plexus and then into the internal vertebral plexus of veins. This metastatic is possible because of valveless communication* between the periprostatic and vertebral plexus of veins. Points of importance - Most common sites* of bony metastatic for prostatic CA-: Pelvis > Lumbar vertebra > thoracic vertebra > head of the femur > the ribs > the humerus (Note that both Bailey and S.Das agree that pelvis* is the most common site for bony metastasis) Bony metastasis of prostate CA are mainly osteoblastic* and cause sclerotic lesions.