A 70-year-old man comes to the office due to 3 weeks of unrelenting low back pain. He was grocery shopping when he first noticed the pain. The patient reports no trauma or leg weakness but describes having to strain to urinate. He has a history of hypertension and hyperlipidemia and has not seen a doctor in the past 5 years. His wife died a year ago, and he now lives alone. The patient is a retired construction worker and has a history of tobacco and marijuana use. There is tenderness in the lower vertebral area. Imaging study of the spine reveals several osteoblastic lesions in the lumbar vertebrae. Which of the following structures was most likely involved during the spread of this patient's disease?

Question

A 70-year-old man comes to the office due to 3 weeks of unrelenting low back pain.  He was grocery shopping when he first noticed the pain.  The patient reports no trauma or leg weakness but describes having to strain to urinate.  He has a history of hypertension and hyperlipidemia and has not seen a doctor in the past 5 years.  His wife died a year ago, and he now lives alone.  The patient is a retired construction worker and has a history of tobacco and marijuana use.  There is tenderness in the lower vertebral area.  Imaging study of the spine reveals several osteoblastic lesions in the lumbar vertebrae.  Which of the following structures was most likely involved during the spread of this patient's disease?

Quizplus · Accepted Answer

This elderly man with new back pain, urinary symptoms, and osteoblastic lesions in the lumbar spine likely has prostate cancer with metastases to the bone. After regional lymph nodes, liver, and lungs, the skeletal system is the fourth most common site of metastases, which usually disseminate hematogenously. Cancers of the pelvis, including the prostate, spread to the lumbosacral spine via the vertebral venous plexus (VVP). The VVP communicates with a number of venous networks, including the prostatic venous plexus, which receives the venous supply from the prostate, penis, and bladder. It runs up the entire spinal column and connects with the venous supply of the brain via a valveless system, which allows for bidirectional flow and regulation of intracranial pressure. This venous connection to the cerebral circulation may help explain the propensity of tumors to metastasize to the brain. (Choices A and F) The VVP also communicates with the azygos vein in the chest, which explains in part why breast and lung cancers frequently metastasize to the thoracic spine. Similarly, due to pulmonary venous drainage into the left side of the heart, lung tumors often spread systemically via the arterial system. (Choices B and D) Although lymph nodes are the most common sites of metastasis in general, lymphatic spread to the skeletal system is very rare. (Choice C) The pampiniform plexus receives venous drainage from the testis, epididymis, and ductus deferens and drains into the testicular veins. Educational objective: The skeletal system is a common site of metastasis due to hematogenous seeding. Cancers of the pelvis, including the prostate, spread to the lumbosacral spine via the vertebral venous plexus, which in turn communicates with a number of venous networks, including the prostatic venous plexus. __________ References: The cerebrospinal venous system: anatomy, physiology, and clinical implications. (http://www.ncbi.nlm.nih.gov/pubmed/16915183) The craniospinal venous system. (http://www.ncbi.nlm.nih.gov/pubmed/16960456) Physiopathology of spine metastasis. (http://www.ncbi.nlm.nih.gov/pubmed/22312491)

A 70-Year-Old Man Comes to the Office Due to 3