Heterotropic Bone Formation Flashcards
(24 cards)
Bone formation in soft tissues or where bone doesn’t normally exist is…
Heterotopic ossification (HO)
Where is the acquired form of HO most frequently seen?
Musculoskeletal trauma (M/C) [also, spinal cord injury/paralysis]
The severity of heterotopic bone formation depends on the size ____ -cm and number of mineralized bone fragments
> 1cm
Post-traumatic Mysoitis Ossificans (MO) is a _____ process characterized by heterotopic ossification usually within ____ muscles.
- Benign
- Large
The radiographic-clinical importance of MO stems from its ability to mimic more ___________ (eg. __)
aggressive pathological processes (eg. osteosarcoma)
What is the clinical presentation of MO most commonly viewed by?
Radiography and CT scanning
What is the physical clinical presentation of the site of soft tissue ossification?
- Fever
- ST swelling
- Poor mobility
______ is essentially metaplasia of the intramuscular connective tissue resulting in extraosseous bone formation…
Myositis ossificans
What is the most important feature of MO?
Zonal organization phenomenon
In looking at zonal phenomenon, what are the three characteristics of this development?
- Peripheral well organized mature lamellar bone
- intermediate osseous region
- central immature non-ossified focus
What may exacerbate the existing benign lesion?
Tissue biopsy
MO is known as “_________”
“Don’t touch.” or “Leave it alone lesions”
______ can occur within ____ days after the causative insult.
- Mineralization
- 10-14 days
Calcification from MO usually starts _____ and remains a very important diagnostic feature of _______
- Peripherally
- Zonal phenomenon
Circumferential calcification with a ___ centre, and a ______ that separates the lesion from the cortex of the adjacent bone.
- lucent centre
- radiolucent cleft STRING sign
Calcification of this lesion begins to become apparent on radiographs at what time interval?
2-6 weeks
The lesion of MO reaches its classic well circumscribed peripherally calcified appearance by ____ months.
2 months
The lesion in MO will end up doing what?
Become smaller and denser
What is the most likely cause of post-traumatic MO?
Blunt trauma [this is due to the bleeding/hematoma deep within the muscle]
Myositis Ossificans - what sign separates the lesion from the cortex?
Cleft-string sign
MO helped to differentiate from aggressive lesions by formation of what?
Zonal phenomenon
Marked osteopenia and Heterotopic bone formation in what type of patient, and usually occurs where in this type of patient?
- Paraplegic patient
- Pelvis/Hip
Post-traumatic MO should be differentiated from a form of sever and progressively fatal congenital disorder known as _______
Fibrodysplasia ossificans progressive (FOP)
[LOOK AT SLIDE 16-18 for pictures of this]
What is the difference between extra-osseous or extra-skeletal osteosarcoma vs. Zonal phenomenon?
osteosarcoma has more of a sclerotic center due to aggressive bone formation - Zonal proliferation has a sclerotic periphery [almost rim like with a radiolucent center]
