Misclassification of melanocytic lesions

From dermoscopedia

Main PageExceptions to rules & mimickersMisclassification of melanocytic lesions
(0 votes)

 Authored by: Ayelet Rishpon     ·  Ashfaq A. Marghoob

 Keywords:   melanocytic · algorithm
Description this chapter describes the misclassification of melanocyticThis glossary term has not yet been described. lesions in 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.
Author(s) Ayelet Rishpon · Ashfaq A. Marghoob
Owner Ash Marghoob→ send e-mail
Status released
Status update July 9, 2018
Status by Ralph P. Braun


Misclassification of melanocytic lesions

When melanocytic lesions do not display clear-cut melanocytic features, or on the contrary show features associated with non melanocytic lesionsThis glossary term has not yet been described., the diagnostic process could result in their misclassification as non-melanocytic.

Melanomas mimicking Basal cell carcinomas

When a melanomaThis glossary term has not yet been described. expresses a pink background, crystalline structuresThis glossary term has not yet been described. and/or arborizing vesselsanalytic term is branched vessels; Bright red sharply in focus large or thick diameter vessels dividing into smaller vessels; BCC, it could be misdiagnosed as a basal cell carcinomais the most common skin cancer, and one of the most common cancers in the United States.[1] While BCC has a very low metastatic risk, this tumor can cause significant disfigurement by invading surrounding tissues. Of the features noted above only arborizing vessels are considered specific for basal cell carcinomas, having a PPD of 94%. However, this feature has been described infrequently in melanomas, challenging the dermoscopic distinction of the two entities and having the final 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 made by the pathologist.

Melanomas mimicking benignis any condition that is harmless in the long run non-melanocytic lesions

Melanomas occasionally display features seborrheic keratosesThis glossary term has not yet been described. such as milia-like cystsThis glossary term has not yet been described. and comedo-like openings[[Comedo like openings]]. One should remember not to rule out a melanocytic lesion by noticing non-melanocytic structures. Adhering to the algorithms’ first step by deciding whether a lesion is melanocytic based on the presence or absence of a networkThis glossary term has not yet been described., globulesThis glossary term has not yet been described., streakslines radial (always at periphery) streaks Reed nevus melanoma recurrent nevus or a homogenous blue pattern, would helpRefers to giving assistance or support to others for mutual benefit avoiding this misclassification.

Melanomas mimicking dermatofibromas

The gestalt pattern of melanomas and dermatofibromas can be similar, thus to achieve high diagnostic accuracyThis glossary term has not yet been described. it is imperative to notice specific structure which support the global pattern. As stated above, contrary to dermatofibromas, melanomas generally do not show vesselsThis glossary term has not yet been described. and crystalline structures within the scar-like areas and lack a dimple sign. However, whenever an atypical dermatofibromaDermatofibromas are hard solitary slow-growing papules (rounded bumps) that may appear in a variety of colours, usually brownish to tan; they are often elevated or pedunculated. A dermatofibroma is associated with the dimple sign; by applying lateral pressure, there is a central depression of the dermatofibroma. is suspected a reasonable managementThis glossary term has not yet been described. strategy would be to biopsy the lesion.

melanomas mimicking lichen planusThis glossary term has not yet been described.-like keratosis

Both melanomas and LPLKThis glossary term has not yet been described.’S can feature pigmentation and extensive regression structure making their distinction occasionally challenging. A clue to lplkThis glossary term has not yet been described.This glossary term has not yet been described.’s diagnosis is a seborrheic keratosisThis glossary term has not yet been described. or solar lentigoThis glossary term has not yet been described. at the periphery of the lesion and rather coarse blue gray granules in contrast to the fine granularityThis glossary term has not yet been described. associated with melanoma. In addition, both lesions can at times exhibit a pink structureless pattern with remnants of a pigment networkGrid-like pattern consisting of interconnecting pigmented lines surrounding hypopigmented holes., and the definite diagnosis is rendered though histologic examination.

Melanomas mimicking pyogenic granulomas

Both amelanotic melanomas and pyogenic granulomas can present as red evolving nodules, occasionally ulcerated or eroded. Pyogenic granulomas can exhibit vascular structuresThis glossary term has not yet been described., further adding to the confusion .Considering the dismal consequences of missing a nodular melanomaThis glossary term has not yet been described., it is strongly suggested that all pyogenic granulomas would be removed and sent to histologic examination.


As the human decision making is an intricate process, its’ reduction into a stepwise linear process can result in oversimplification leading to the incorrect diagnosis. Confusing a melanoma with a malignantThis glossary term has not yet been described. non-melanocytic lesion (ie BCCAbbreviation for Basal Cell Carcinoma or pigmented Bowenalso known as squamous cell carcinoma in situ[1] is a neoplastic skin disease. It can be considered as an early stage or intraepidermal form of squamous cell carcinoma. It was named after John T. Bowen’s disease) would frequently result in similar management. However, confusing a malignant lesion with a benign lesion could have dismal consequences. It is essential to integrate history and clinical features with the algorithmic process and diagnostic cluesEvidence, in an investigation in order to reduce diagnostic errors.

Table 1- Features and mimickers