Conditions of the human integumentary system constitute a broad spectrum of diseases, also known as dermatoses , as well as many nonpathologic states (like, in certain circumstances, melanonychia and racquet nails ).   While only a small number of skin diseases account for most visits to the physician , thousands of skin conditions have been described.  Classification of these conditions often presents many nosological challenges, since underlying etiologies and pathogenetics are often not known.   Therefore, most current textbooks present a classification based on location (for example, conditions of the mucous membrane ), morphology ( chronic blistering conditions ), etiology ( skin conditions resulting from physical factors ), and so on.   Clinically, the diagnosis of any particular skin condition is made by gathering pertinent information regarding the presenting skin lesion (s), including the location (such as arms, head, legs), symptoms ( pruritus , pain), duration (acute or chronic), arrangement (solitary, generalized, annular, linear), morphology ( macules , papules , vesicles ), and color (red, blue, brown, black, white, yellow).  Diagnosis of many conditions often also requires a skin biopsy which yields histologic information   that can be correlated with the clinical presentation and any laboratory data.   
Study 4 was a randomized, multicenter, open-label trial in which 1466 patients were randomized to receive second-line treatment for metastatic NSCLC; 729 patients received IRESSA 250 mg daily and 715 patients received docetaxel. The median duration of treatment with IRESSA was months. The study population characteristics were: median age 61 years, age less than 65 years (61%), female (36%), Caucasian (79%), Asian (21%), NSCLC adenocarcinoma histology (54%), never smoker (20%), ECOG PS 0 or 1 (88%) and two or more prior therapies (16%).