di imaging II exam 3 benign tumors

giant cell tumor (also called an osteoclastoma)

neoplasm that originates from non-bone forming supportive connective tissue of the marrow - 80% are benign and 20% are malignant - age of occurence is 20-40 years - M:F is 1:1

osseous location of giant cell tumor

85% in long bones (distal femur and proximal tibia 50-60%, distal radius, and proximal humerus), 15% in flat bones (pelvis, sacrum near SIJ, spine 5%, rib and skull), lesions of distal radius higher chance of being malignant

what is the most common benign tumor of the sacrum?

giant cell tumor

clinical presentation of giant cell tumor

localized pain (!) of an aching nature, restricted joint motion - malignant variety female to male 1:3

radiographic findings for giant cell tumor

geographic, eccentric, metaphyseal-epiphyseal (extend to the end of the bone), subarticular, expansion/soup bubble/or purely lytic, cortical thinning, short zone of transition

giant cell tumor treatment and prognosis

surgical curettage and with liquid nitrogen freezing, bone packing, or grafting (recurrence rate of 12-50% - radiation often for spinal lesions - 5 year survival for malignant lesions is 10%

solitary osteochondroma

bone exostosis on the external surface of a bone and usually lined by a hyaline cartilage cap - the most common benign osseous tumor (50% of all benign bone tumors) - unknown cause, displaced cartilage from the physis - seen in those under 20 years old with M:F is 2:1

clinical features of solitary osteochondroma

most are asymptomatic, unless they disturb surrounding nerves or vessels, complaints of a painless hard mass, pain from a fractured stalk or cord compression with spinal lesions, obstructive uropathy from pelvic tumor, pain and new growth may indicate malignant transformation

sessile solitary osteochondroma

has a broad base and no stalk, common in the humerus and scapula

pedunculated solitary osteochondroma

has a long stalk with a cartilage cap, common in knee, hip, and ankle - coat hanger exostosis, cauliflower cap

location for solitary osteochondroma

metaphysis of long bones (femur and tibia 50%, humerus, proximal radius), flat bones (scapula, ribs, pelvis, spine 1-5%), any bone formed by enchondral ossification

radiographic features of solitary osteochondroma

metaphyseal bone exostosis, peduculated and/or sessile, en face may appear as a dense cortical rim around an area of lucency, sessile lesion may cause metaphyseal widening or appear as an asymmetrical bump, growth stops when growth plates close (if it’s still growing, think malignancy), malignant degeneration 1%

radiographic appearance of solitary osteochondroma

cortex and spongiosa blend imperceptibly with the host bone, growth is at an angle to the long axis and towards the midshaft (project away from the joint - coat hanger exostosis), if multiple are present and it’s widespread, usually there’s a family history and is hereditary multiple exostosis