MSK: Random Trivia Flashcards
Liposclerosing myxofibroma
Note: Lucent lesion with sclerotic border in the intertrochanteric region.
Why is it important to follow liposclerosing myxofibroma?
10% undergo malignant degeneration (mostly to osteosarcoma)
What is the only benign skeletal tumor associated with radiation?
Osteochondroma
Osteochondroma
Can osteochondroma undergo malignant transformation?
Yes, to chondrosarcoma
How can you estimate the risk of an osteochondroma undergoing malignant degeneration?
Look at the size of the cartilage cap
Note: A cap > 1.5 cm is concerning for malignant transformation.
Osteochondromas of the posterior knee are associated with an increased risk of…
Popliteal artery pseudoaneurysm
How can you differentiate an osteochondroma from dysplasia epiphysealis hemimelica?
Osteochondromas are exostoses that point away from joints
Dysplasia epiphysealis hemimelica (AKA Trevor disease) involves exostoses that point into the joint, which is why they cause so many joint issues
Is there bone marrow within osteochondromas?
Yes, which is classically seen on T1 images
Multiple hereditary exostoses
An autosomal dominant condition with multiple osteochondromas (sessile and/or pedunculate)
Trevor disease
AKA dysplasia epiphysealis hemimelica: A disease characterized by the development of osteochondromas at the epiphysis which result in significant joint deformity (rather than pointing away from the joint like normal osteochondromas, these point into the joint and cause problems)
Treatment for dysplasia epiphysealis hemimelica (AKA Trevor disease)
Surgical excision of the epiphyseal osteochondromas that are causing joint problems
Think dysplasia epiphysealis hemimelica (AKA Trevor disease)
Note: Osteochondroma arising from an epiphysis (especially distal femur). These cause joint problems are are treated with surgical excision.
Dysplasia epiphysealis hemimelica (AKA Trevor disease)
Note: These cause joint problems are are treated with surgical excision.
Supracondylar spur (AKA Avian spur)
Note: This is a normal variant that can compress the median nerve. You know this is not an osteochondroma because it points towards the joint.
An Avian spur can lead to compression of the…
Median nerve (compression is by the ligament of Struthers, which attaches to the supracondylar spur)
Pediatric pt
Think periosteal chondroma (AKA junta-cortical chondroma)
8 y/o
Think osteofibrous dysplasia
Note: This looks like a nonossifying fibroma in the anterior tibia with associated tibial bowing in a pt under age 10. It occurs with Adamantinoma (cannot distinguish the two on imaging).
Cortical desmoid (AKA distal femoral metaphysis irregularity), a normal finding
Note: This is a lucency seen along the back of the posteromedial aspect of the distal femoral metaphysis. It is often bilateral. This is a normal finding (do not touch lesion, no MRI, no biopsy).
What is the most common location for hydroxyapatite deposition?
The shoulder (specifically the supraspinatus tendon)
Calcific tendonitis (calcium hydroxyapatite deposition disease)
Neck pain
Calcific tendonitis of the longus coli
What are the common causes of secondary calcific tendonitis?
- Chronic renal disease
- Collagen-vascular disease
- Tumoral calinosis
- Hypervitaminosis D
Osteopoikilosis (idiopathic or autosomal dominant development of numerous bone islands)
Note: Numerous bone islands centered around a joint (if bone islands are more randomly distributed, consider sclerotic metastases).
Pts with osteopoikilosis tend to be predisposed to ______ formation
Keloid
Osteopathia striata (linear parallel longitudinal lines in the metaphyses of long bones)
Note: This usually doesn’t mean anything but can be associated with pain.
Engelmann’s disease (AKA progressive diaphysial dysplasia)
Note: Fusiform bony enlargement and sclerosis of the long bone diaphyses. It is bilateral and symmetric.
Can Engelmann’s disease affect the skull?
Yes, where the bony enlargement/sclerosis can cause optic nerve compression