Level 10: Lesions requiring context
|Description||This chapter describes the dermoscopyThe examination of [skin lesions] with a 'dermatoscope'. This traditionally consists of a magnifier (typically x10), a non-polarised light source, a transparent plate and a liquid medium between the instrument and the skin, and allows inspection of skin lesions unobstructed by skin surface reflections. Modern dermatoscopes dispense with the use of liquid medium and instead use polarised light to cancel out skin surface reflections. pattern of lesions requiring contect|
|Author(s)||Ralph P. Braun · Aimilios Lallas · Ashfaq A. Marghoob|
|Owner||Ash Marghoob → send e-mail|
|Status update||July 2, 2018|
|Status by||Ralph P. Braun|
Step 2 If a specific diagnosisis the identification of the nature and cause of a certain phenomenon. Diagnosis is used in many different disciplines with variations in the use of logic, analytics, and experience to determine "cause and effect". In systems engineering and computer science, it is typically used to determine the causes of symptoms, mitigations, and solutions cannot be rendered then the observer moves to the second step of the algorithmIn mathematics and computer science, an algorithm (Listeni/ˈælɡərɪðəm/ AL-gə-ri-dhəm) is a self-contained sequence of actions to be performed. Algorithms can perform calculation, data processing and automated reasoning tasks.. Therefore, the second step includes lesions that are suspicious for melanomaThis glossary term has not yet been described. and lesions that cannot be safely diagnosed. The latter group of morphologically equivocal tumors consists mainly of neviThis glossary term has not yet been described. that demand special attention, but also of some melanomas lacking the usual disorganized distribution of structuresThis glossary term has not yet been described. and colorsThis glossary term has not yet been described.. Consequently, the main goal of the second step is to maximize melanoma detection and, thus, all lesions entering the second step should be evaluated for the presence or absence of melanoma specific patternsThis glossary term has not yet been described. and structures.
As a principleThis glossary term has not yet been described., the second step analysis should be always performed in conjunction with the overall clinical contextThis glossary term has not yet been described. of the lesion. This is because the diagnostic usefulness of each dermoscopic criterion for melanoma depends on the other tumors included each time in the differential diagnosis. Often, the differential diagnosis is narrowed by clinical data, since one or more diagnoses might be excluded (or considered very unlikely) based on epidemiologic characteristics of the patient (ex. ageprocess of becoming older). Therefore, the dermoscopic analysis should be adjusted each time to the clinically established differential diagnosis and aim to narrow it further.
Examples: i) A recently appeared pigmented macule in a 70 years old man, dermoscopically displaying regularly distributed brown dotsDots are small, round structures of less than 0.1 mm in diameter that have a red color when corresponding to blood vessels; however, when due to melanin, their color ranges from black, brown, to blue-gray depending on the depth and concentration of the melanin in the skin (Tyndall effect).: Regular dotsDots clustered at the center of the lesion, or located on the network lines (also called target network) are considered as suggestive of a nevusThis glossary term has not yet been described.. However, the diagnosis of a nevus is not included in the clinical differential diagnosis of a pigmented lesion developing at this age. Therefore, an epidemiologic characteristic (age) narrows the differential diagnosis into 2 main possible entities: melanoma and seborrheic keratosisThis glossary term has not yet been described./solar lentigoThis glossary term has not yet been described.. Between these 2 diagnoses, brown dots are strongly suggestive of melanoma. ii) Atypical networkNetwork with increased variability in the color, thickness, and spacing of the lines of the network; asymmetrically distributed; gray color is generally considered a melanoma-specific criterion. However, in a young individual with multiple atypical neviNevi that clinically look like melanoma but that histopathologically are not melanomas, a degree of networkThis glossary term has not yet been described. atypia in a nevus might be tolerated, especially in the presence of additional nevi with similar features. Precisely the same aspect in a solitary lesion would be considered as highly suspicious. iii) A pigmented lesion dermoscopically typified by regularly distributed peripheral streakslines radial (always at periphery) streaks Reed nevus melanoma recurrent nevus: in a child would be considered as diagnostic of Reed nevusThis glossary term has not yet been described.. In an individual of 60 years the same pattern would be strongly suspicious for melanoma. iv) A non-pigmentedThis glossary term has not yet been described. lesion dermoscopically displaying dotted vesselstiny pinpoint vessels flat melanocytic lesions inflammatory diseases Bowen disease: In a child, the differential diagnosis would include a Spitz nevusThis glossary term has not yet been described. and a viral wart. In an elderly individual, the differential diagnosis would include melanoma, intraepidermal carcinoma and lichen-planus like keratosis.