Benign+Heterotopic+Bone

But can include. Typically symptoms are || []. []. ||
 * **Epidemiolgy:** || Heterotropic bone formation or ossification occurs in 30% of patients undergoing hip arthroplasty. [1] ||
 * **Etiology:** || Patients who have a history of ipsilateral or contralateral heterotropic hig ossification have a higher incidence of greater than 80%. Those with other high-risk factors such as hypertrophic arthritis, ankylosing spondylitis, and diffuse idiopathic skeletal hyperostosis have a higher incidence of 60%. [1] ||
 * **Signs & Symptoms:** || Heterotopic ossification will develop in 10-80% for cases with trauma to the hip and leg.[1] The most common post surgical site is the hip following total hip arthroplasty when the abnormal formation of bone within extra-skeletal soft tissues. The hip is also the most common site in patients with traumatic brain injury or spinal cord injury but can be found at any site in the body.[1]
 * Knees (frequently with spinal cord injuries)
 * Shoulders
 * elbows
 * acute inflammation
 * swelling (proximal to surgical site)
 * increased temperature ||
 * **Diagnostic Procedures:** || Diagnostic procedures can include but not limited to[3]
 * x-ray
 * 3 phase bone scan (earliest method)
 * Ct scan
 * PET scan
 * Ultrasounds ||
 * **Histology:** || Within 1 week of the index trauma, heterotopic ossification commences with a spindle cell proliferation. Within a few days of the spindle cell proliferation, peripheral primitive osteoid develops. Two weeks after index trauma, primitive cartilage and woven bone develops. Trabecular bone begins to appear 2-5 weeks after the index trauma. If a biopsy is performed on heterotopic ossification at 6 weeks following the index trauma, specimens reveal immature undifferentiated tissues centrally with mature lamellar bone peripherally, known as the zonal phenomenon.
 * **Lymph node drainage:** || Because heterotopic bone does not spread to other sites, there is no lymphatic drainage. ||
 * **Metastatic spread:** || This diagnosis does not metastasize to distant sites, but in extremely rare cases malignant degeneration to osteosarcoma can occur. ||
 * **Grading:** || Grading involves analyzing the cellular structure of a lesion to determine the abnormality and rate of growth of the tissues involved. A tumors grade effects the decision to treat or not and what options may be available for the patient. Grading also effect the predicted prognosis of the patient. Since a benign diagnosis is not cancerous, grading is not available.[2] ||
 * **Staging:** || Staging describes the extent or severity of the tumor and spread. This included the primary tumor site, size, nodal involvement, cell grade, and metastasis. Benign lesions are not cancerous and no staging is available.[2] ||
 * **Radiation side effects:** || Skin may temporarily become red, dry, itchy, and scaly after treatment.[3] ||
 * **Prognosis:** || Heterotopic bone formation appears in 30% of patients that have a hip arthroplasty. [1] This is not a cancerous formation. ||
 * **Treatments:** || Usually we treat a heterotopic bone with radiation therapy post-operatively. the dose given would be 7 Gy in one fraction. [1]
 * **TD 5/5:** || The TD 5/5 is not used for heterotopic bone. ||
 * **References:** || # Chao KS, Perez CA, Brady LW. Radiation Oncology: Management Decisions. Philadelphia, PA: Lippincott Williams & Wilkins; 2002.
 * 1) Cancer staging/ grading. Available at: http://www.cancer.gov/cancertopics/factsheet/detection/staging. Accessed on July 2,2012.
 * 2) // The Prevention of Heterotopic Ossification in High-risk Patients by Low-dose Radiation Therapy After Total Hip Arthroplasty. Available at: // [|http://www.ncbi.nlm.nih.gov]. Accessed on july 4,2012
 * 3) Reference: McLean, C. Traumatic Heterotopic Ossification Workup. Medscape Reference. May 2011. Available at: [|http://emedicine.medscape.com/article/1254416-workup#a0723]. Accesson: July 5, 2012. ||

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