Answer and Discussion of Quiz Set: W-001

2.    Metastatic carcinoma is more common to be found in the axial skeleton?

A.  True

B.  False

Answer and Discussion: The answer is (A). Bone metastasis is present in about 70% of patients at autopsy who died of cancer but many of them are asymptomatic and too small to be detected by radiographic methods. One of the reason for metastasis to be more common in the axial skeleton is the persistence of red marrow in these locations. Metastasis to the fatty marrow in adults are far less common. WIth this token, the femoral head and neck is far more likely to harbor metastasis than the femoral shafts in adults. The most common initial metastasis are see in the vertebral column particularly the thoracolumbar spine, ribs, pelvis, and occasionally cranial bone. Tumor cells can enter the vertebral circulation through Batson's vertebral venous plexus without first passing through the lung. The Batson's vertebral venous plexus is a network of valveless veins that connect the deep pelvic veins and thoracic veins to the internal vertebral venous plexuses. Both infection and malignancy arising in the pelvis including the rectum, prostate, and ovary can spread through this plexus.

Further Reading:

Osteolytic metastatic tumors:http://radiopaedia.org/articles/lytic-bone-metastases

Osteosclerotic tumors: http://radiopaedia.org/articles/sclerotic-bone-metastases

Skeletal metastasis: http://www.ncbi.nlm.nih.gov/books/NBK12348/