Diagnosis lesions

Limitations are obvious if the diseased tissue does not differ from normal tissue or successfully treated tissue in respect of the above-mentioned criteria. Under these conditions, even a contrast agent with high absorption of X-rays is of no help. Another drawback is the short-lasting contrast which requires repeated injections if the diagnosis is missed during the first scan or if persistent visualization of a lesion is required during an interventional procedure. 

Muscle biopsy is usually undertaken to confirm the provisional clinical diagnosis. Because the skin lesions normally precede those in muscle, biopsies of muscle taken early may show little abnormality. Inflammatory foci may be scanty or absent and muscle fiber diameters may be normal. However typical biopsies show discrete foci of inflammatory cells, with a predominance of B-lymphocytes (see Figure 18). These cells are situated in perimysial connective tissue rather than in the en-domysium and are often also perivascular in location. Muscle fiber necrosis occurs in JDM but muscle fibers do not appear to be the primary target of the disordered immune process. Rather, it is the micro vasculature of the muscle which appears to degenerate first and muscle necrosis is preceded by capillary necrosis, detectable at the ultrastructural level. 

The diagnosis of PIH is often made by history and clinical presentation. It is characterized by macules and patches of varying shades of hyperpigmentation limited to the sites of inflamed skin lesions. Lesions of the preceding inflammatory process may be present at vari-... 

Mastocytosis is recognized in most patients because of the presence of characteristic cutaneous lesions [10]. A positive Darier s sign and/or histological examination of the skin using metachromatic stains, or by immunohistochemistry using antibodies to mast cell tryptase, helps confirm the diagnosis of cutaneous disease. 

If the genetic lesion is understood and a specific probe is available, prenatal diagnosis is possible. DNA from cells collected from as little as 10 mL of amniotic fluid (or by chorionic villus biopsy) can be analyzed by Southern blot transfer. A fetus with the restriction pattern AA in Figure 40-10 does not have sickle cell disease, nor is it a carrier. A fetus with the SS pattern will develop the disease. Probes are now available for this type of analysis of many genetic diseases. 

The cultivation of viruses from material taken from lesions is an important step in the diagnosis of many viral diseases. Studies of the basic biology and multiplication processes of human viruses also require that they are grown in the laboratory under experimental conditions. Human pathogenic viruses can be propagated in three types of cell systems. 

INR > 1.7 (PT > 15 if no INR available) with or without chronic oral anticoagulant use Seizure at onset of stroke (This relative contraindication is intended to prevent treatment of patients with a deficit due to postictal Todd s paralysis or with seizure due to some other CNS lesion that precludes thrombolytic therapy. If rapid diagnosis of vascular occlusion can be made, treatment may be given.)... 

Differentiating an episode of acute pancreatitis from chronic pancreatitis maybe difficult because the clinical presentations can be similar. The diagnosis of chronic pancreatitis is made by looking for the effects of chronic pancreatic inflammation and scarring on the pancreas and the patient as a whole. Computed tomography or ERCP will allow visualization of chronic calcified lesions in the pancreas when present.37... 

Cenital herpes simplex virus. Characterized by vesicular or ulcerative lesions. Diagnosis confirmed by virologic or serologic testing. Prodrome manifests as pain, burning, or itching at the site where lesions will develop. 

Diagnosis of psoriasis is usually based on recognition of the characteristic plaque lesion, and not based on lab tests. 

Folliculitis presents as small, pruritic, erythematous papules. Location of the lesions and a good patient history are often all that are required in the diagnosis of folliculitis. While the papules may be cultured and Gram stains or potassium hydroxide stains done to help determine causative agent, it is not generally required because folliculitis often resolves spontaneously within a few days. 

Tissue biopsy or viral typing is only indicated if diagnosis is uncertain and is not recommended for patients with routine or typical lesions. 

Currently, the choice of therapy is based on the size, site, and morphology of lesions, as well as patient preference, treatment costs, convenience, adverse effects, and patient experience. Assuming that the diagnosis is correct, switching to alternate therapy is appropriate if there has been no response observed after three treatment cycles. A comparison of adverse effects related to treatment options maybe found in Table 77-2. 

In a patient with a previous diagnosis of genital herpes, the appearance of new vesicular lesions is synonymous with HSV reactivation. For most patients, genital herpes recurrence is self-limiting and short-lived, lasting approximately 6 to 7 days. 

Diagnosis is primarily based on identification of characteristic lesions. Although rarely necessary, diagnostic testing is possible if a definitive diagnosis is required. 

Unlike OPC, diagnosis of esophageal candidiasis is not based solely on clinical presentation, instead requiring endoscopic visualization of lesions and culture confirmation. Due to the invasive nature of these procedures, most practitioners opt to treat the infection presumptively, reserving endoscopic evaluation for patients who fail therapy. 

As many as 85% of American women have lumpy breasts and may have a clinical diagnosis of fibrocystic breast disease or benign breast disease. Data suggest that benign breast disease or fibrocystic disease is most often not associated with proliferation and that these women are not at an increased risk for developing breast cancer.4 However, it must be noted that lumpy breasts may lead to a delay in diagnosis of breast cancer because of an inability of the patient or physician to detect a true malignant lesion. 

The pathologic evaluation of breast lesions serves to establish the histologic diagnosis and to confirm the presence or absence of other factors believed to influence prognosis. These prognostic factors include the presence of necrosis, lymphatic or vascular invasion, nuclear grade, hormone receptor status, proliferative index, amount of aneuploidy, and HER-2/neu expression. 

The least expensive visualization method in the diagnosis of lung cancer. Readily accessible and does not require systemic administration of contrast dye. However, it often detects lesions that are not cancerous and is not capable of assessing lymph node status. 

The most definitive diagnosis of AD is a postmortem examination of the brain for the presence of two characteristic lesions the neuritic plaque (NP) and the neurofibrillary tangle. Both structures were originally described in 1906 by Alois Alzheimer using silver-based histological stains. The discovery of NPs was hailed as a watershed moment in the history of neurological disease as it helped shift society s perception of age-related dementia from social stigma to physical disease [2]. 

While IHC has become an increasingly important adjunct to pathologic diagnosis, it should not be considered a substitute for a careful morphologic evaluation of clinical biopsy samples. A wise pathologist once said, if you do not have a pretty good idea of what a lesion is before you stain it, IHC will only turn what you do not know brown, and in all likelihood, you still will not know what the lesion is. ... 

Peters, R. A. The biochemical lesion in vitamin B1 deficiency. Application of modern biochemical analysis in its diagnosis. Lancet 1 1161-1164,1936. 

---