Myositis Ossificans: Causes, Diagnosis, Imaging, and Treatment скачать в хорошем качестве

Myositis Ossificans: Causes, Diagnosis, Imaging, and Treatment

Join this channel to support the channel    / @nabilebraheim   Myositis ossificans is abnormal bone formation within a muscle, typically following blunt trauma. It can mimic osteogenic sarcoma both on X-ray and histologically on biopsy. This condition is most commonly seen in young, active males and results from trauma to a muscle or soft tissue, or from a hematoma within the muscle. Commonly involved muscles include: Quadriceps Brachialis Gluteal muscles Deltoid Clinical presentation involves pain, tenderness, swelling, and decreased range of motion—usually appearing within days after the injury. In some cases, the presentation includes a painless, enlarging mass with reduced motion, typically noted weeks after trauma. It is a self-limiting condition. Radiographic findings begin to appear around three weeks post-injury, with faint, irregular soft tissue densities visible on X-ray. This early appearance is sometimes referred to as a "dotted wheel" pattern. As the condition progresses, a zoning pattern emerges. This is characterized by peripheral mineralization (resembling an eggshell) made of lamellar bone, and a lucent central area composed of immature tissue. This peripheral maturation is the opposite of what is seen in malignant tumors such as osteosarcoma, where the central portion is more mature. Differential diagnosis includes: Extraskeletal osteosarcoma Parosteal osteosarcoma In malignant tumors, the center is more ossified, while the periphery remains lucent. On X-ray, the calcified or ossified lesion in myositis ossificans may not be attached to bone. A CT scan often confirms the eggshell appearance, and a bone scan will typically show increased activity (hot spot). Treatment usually begins when the patient presents with a painless mass appearing 2–4 weeks after injury. These patients are often young, active males who experience limited range of motion. Initial management includes: Rest Activity modification Physical therapy to maintain and restore range of motion Do not surgically excise the lesion in early stages, as this can result in recurrence. The size of the mass usually decreases after one year, and follow-up X-rays are essential. Surgical excision, if necessary, should be delayed until the lesion becomes fully mature, typically around one year post-injury, and when there is no increased uptake on bone scan. Early surgery is controversial, as it carries a higher risk of recurrence. There is a related condition called fibrodysplasia ossificans progressiva (FOP). In this rare genetic disorder, patients experience generalized stiffness of the spine and joints due to progressive heterotopic ossification, eventually leading to a frozen spine and joints. The ACVR1 gene is implicated in FOP. Quizzes 1. What is the most common cause of myositis ossificans? ✔️ a) Blunt trauma b) Autoimmune disease c) Infection d) Radiation Explanation: It typically results from direct trauma to muscle, causing hematoma and ossification. 2. Which muscle is most commonly involved in myositis ossificans? a) Biceps femoris b) Triceps ✔️ c) Quadriceps d) Psoas Explanation: The quadriceps is the most frequently affected muscle due to sports trauma. 3. What best describes the radiographic appearance of mature myositis ossificans? a) Central mineralization and peripheral lucency b) Complete radiolucency ✔️ c) Peripheral ossification with central lucency d) Diffuse homogeneous calcification Explanation: The lesion matures from the outside in, creating a zoning pattern. 4. What feature distinguishes myositis ossificans from osteosarcoma? a) Painful swelling ✔️ b) Peripheral bone maturation c) Central bone necrosis d) Bone marrow involvement Explanation: Myositis ossificans has mature bone at the periphery; osteosarcoma has central maturation. 5. When do early X-ray findings typically appear in myositis ossificans? a) Within 3 days b) 1 week ✔️ c) 3 weeks d) 6 months Explanation: X-ray changes such as faint calcification appear around 3 weeks after injury. 6. Which imaging best shows the eggshell ossification? a) Ultrasound ✔️ b) CT scan c) MRI d) Bone scan Explanation: CT is best for showing peripheral ossification and the classic zoning. 7. What is the initial treatment for early-stage myositis ossificans? a) Immediate surgery b) Radiation therapy ✔️ c) Rest and physiotherapy d) Chemotherapy Explanation: Rest, activity modification, and ROM exercises are first-line management. 8. When is surgical excision appropriate for myositis ossificans? a) Immediately after diagnosis b) After 4 weeks ✔️ c) After 1 year, once lesion matures d) After bone scan shows increased uptake Explanation: Surgery should be delayed until maturation to reduce recurrence. 9. What is a typical clinical symptom of myositis ossificans? a) Fever ✔️ b) Decreased range of motion c) Night sweats d) Bruising of the foot Explanation: Ossified muscle limits movement, even if painless.