Pterygium+(Benign)

"Internationally, the relationship between decreased incidence in the upper latitudes and relatively increased incidence in lower latitudes persists." 3 || ---the deep parotid lymph nodes which can be broken down into 2 groups: --- the submaxillary lymph nodes which are scattered over the infraorbital region. They are located from the groove between the nose and cheek to the zygomatic arch. ---the buccal lymph nodes which are scattered over the buccinator muscle. 1
 * Epidemiology: || The highest incidence of disease occurs in hot, dry, dusty and sun exposed regions, even people in there 20s and 30s are affected. 3 ||
 * Etiology: || "Occurrence within the United States varies with geographical location. Within the continental United States, prevalence rates vary from less than 2% above the 40th parallel to 5-15% in latitudes between 28-36°. A relationship is thought to exist between increased prevalence and elevated levels of ultraviolet light exposure in the lower latitudes."  3
 * Signs & Symptoms: || Pterygium are external to the eye, visibly apparent, and typically noted to grow before they cause symptoms. They can become irritated, causeing an itchy, burning sensation. If allowed to grow into the line of vision (pupillay axis), then a pterygium can cause impairment of vision. 8 ||
 * Diagnostic Procedures: || Pterygium is usually a clinical diagnosis based on appearance. An excision is usually suggested. When surgery is performed, the excised tissue should be sent to pathology for a histopathologic diagnosis. 8 ||
 * Histology: || An electron microscope study of the cap areas of several ptergia shows the presence of active fibroblasts in the natural tissue planes surrounding the Bowman's layer. 8 ||
 * Lymph Node Drainage: || Lymph drainage from the eye is:
 * <span style="color: #008000; font-family: 'Times New Roman',Times,serif; font-size: 110%;">the first group is embedded in the parotid gland. Its superior border is the TMJ, posterior border is the mastoid process, inferior border is the angle of the mandible, and the anterior border is the anterior ramus.
 * <span style="color: #008000; font-family: 'Times New Roman',Times,serif; font-size: 110%;">the second group is the subparotid nodes which are "located deep to the gland and lie on the lateral wall of the pharynx."

<span style="color: #008000; font-family: 'Times New Roman',Times,serif; font-size: 100%;">Figure 1. Diagram of head and neck lymph nodes. <span style="color: #008000; font-family: 'Times New Roman',Times,serif; font-size: 100%; vertical-align: super;">1 <span style="color: #008000; font-family: 'Times New Roman',Times,serif; font-size: 100%;"> || <span style="color: #0000ff; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Figure 2 || - Single dose of 2Gy = cataract. - Fractionated dose of 8Gy = cataract. - 48Gy = corneal injury. - Doses > 50Gy result in retinal damage. Retinopathy, retinal atrophy cause gradual vision loss. - Doses > 60Gy increase the risk of optic nerve atrophy. <span style="color: #0000ff; font-family: 'Times New Roman',Times,serif; font-size: 88%; vertical-align: super;"> 5 || <span style="color: #008080; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Table provided by Wikibooks. <span style="color: #008080; font-family: 'Times New Roman',Times,serif; font-size: 77%; vertical-align: super;">6 || References: <span style="color: #008000; font-family: 'Times New Roman',Times,serif; font-size: 110%;">1. Washington CM, Leaver D. //Principles and Practice of Radiation Therapy.// 2nd edition. St. Louis, MO: Mosby, Inc. 2004: 389. 2. Nature Publishing Group. Overexpression of p53 Tumor Suppressor Gene in Ptreygia. Available at: http://www.nature.com/eye/journal/v16/n5/full/6700150a.html. Accessed February 15, 2010. <span style="color: #ff00ff; font-family: 'Times New Roman',Times,serif;">3. Fisher JP, Trattler WB. //Pterygium. 2009. Emedicine. Retrieved February 19,2010, from// []. 4. Hawaiian Eye Center website avaliable at http://www.hawaiineye.com/othereye/pterygium.php. Accessed on Feb. 18, 2010. 5. Chao CK, Brady LW. //Radiation Oncology Management Decisions.// Second Edition. Philadelphia, PA: Lippincott Williams & Wilkins. 2002. 177-181, <span style="color: #008080; font-family: 'Times New Roman',Times,serif; font-size: 110%;">678. <span style="color: #008080; font-family: 'Times New Roman',Times,serif; font-size: 110%;">6. Radiation Oncology/Toxicity/Emami. Wikibooks. Available at: <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;">[]. <span style="color: #008080; font-family: 'Times New Roman',Times,serif; font-size: 119.79%;">Accessed: January 5, 2010. <span style="color: #ff00ff; font-family: 'Times New Roman',Times,serif;">7. Pterygium. 2007. Retrieved on February 19, 2009, from Neovision Eye Center website at: [] 8. Eye Cancer Network. Pterygium. Available at: []. Accessed February 21, 2010.
 * Metastatic Spread: || <span style="color: #008000; font-family: 'Times New Roman',Times,serif; font-size: 110%;">"It is known that pterygium is a lesion with limited local invasion and inability to send metastases." <span style="color: #008000; font-family: 'Times New Roman',Times,serif; font-size: 88%; vertical-align: super;">2 ||
 * Photos: || <span style="font-family: 'Times New Roman',Times,serif; font-size: 110%;"> Figure 2 is an example of a pterygium. 4
 * Grading and Staging: || <span style="color: #0000ff; font-family: 'Times New Roman',Times,serif; font-size: 110%;">There is not a staging or grading system for this benign disease. Early symptoms of a pterygium include eye irritation. ||
 * Radiation Side Effects: || <span style="color: #0000ff; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Radiation Therapy side effects include: erythema, depigmentation, atrophy, and telangiectasia (dilated superficial blood vessels).
 * Prognosis: || <span style="color: #ff00ff; font-family: 'Times New Roman',Times,serif; font-size: 110%;">"Most pterygia grow slowly and almost never cause significant damage, so the prognosis is excellent. Again, a diagnosis must be made to rule out other more serious disorders. The risks of pterygium excision surgery are low and, in general, if the pterygium is excised before it encroaches to the center area of the cornea, the prognosis for post-operative vision is excellent. Pterygia often come back after surgical removal. These recurrent-pterygia probably have no relationship with exposure to ultraviolet radiation." <span style="color: #ff00ff; font-family: 'Times New Roman',Times,serif; vertical-align: super;">7 ||
 * Treatments: || <span style="color: #008080; font-family: 'Times New Roman',Times,serif; font-size: 110%;">Surgery if the treatment of choice for pterygium, but the recurrance rate is 20-30% with surgery alone. One study reported a recurrence rate of only 1.4% in 1,300 pterygia in 1,064 patients treated with prophylatic postoperative beta-ray therapy with a strontium-90 applicator. Treatment consisted of 8-10 Gy given for each of three applications on days 0, 7, and 14 after the operation. Similar outcomes to other studies have been reported using this treatment option. Beta-radiation is more effective when given at the time of surgery rather than 4 days later. 5 ||
 * TD5/5: || [[image:eye_TD_5.5new.jpg width="307" height="229"]]