Clark's nevus

Clark nevus, also referred to as a dysplastic nevus, is a specific type of pigmented skin lesion characterized by features intermediate between a benign nevus and malignant melanoma (melanoma malignum). These lesions exhibit architectural and cytological atypia of melanocytes, but do not meet the criteria for a diagnosis of malignancy. Clark nevus is considered a marker of increased risk for the development of melanoma, especially in individuals with numerous atypical nevi or a positive family history. In clinical practice, it requires close dermoscopic observation and individual dermatological assessment.

Clark's nevus – what it looks like

Clark's nevus is characterized by a distinctive clinical and dermatoscopic appearance that distinguishes it from typical melanocytic nevi. These lesions most often take the form of irregular spots or slightly elevated foci with varied pigmentation.

The most important clinical features include:

shape asymmetry – lack of regularity and symmetry,
irregular, blurred borders – often merging into the surrounding skin,
varied coloration – from light brown to dark brown, sometimes with shades of pink or black,
diameter over 5 mm, although smaller lesions occur,
flat or slightly elevated surface, sometimes with a papular component.

In the dermatoscopic examination, the following are observed:

irregular pigment network (atypical pigment network),
presence of globular structures of various sizes,
structural and pigmentary asymmetry,
areas of hypopigmentation or regression.

Clark's nevus is most commonly located on:

the trunk (especially the back),
the limbs,
less frequently on the face.

An important aspect is the fact that these lesions can exhibit a dynamic nature, which means the possibility of slow evolution of appearance over time. This is why monitoring changes using videodermatoscopy and photographic documentation is of key importance.

It is worth emphasizing that a single Clark's nevus does not determine the development of melanoma, whereas the presence of numerous dysplastic nevi defines the so-called dysplastic nevus syndrome, which is associated with a significantly increased oncological risk.

Clark's nevus – how to treat

The management of Clark's nevus is based on the principle of vigilant oncological observation and selective surgical intervention. Not every lesion requires removal – the therapeutic decision depends on clinical and dermoscopic assessment as well as the patient's risk factors.

1. Observation and dermatological control

In most cases, the following is recommended:

regular dermoscopic examinations (every 6–12 months),
photographic documentation of lesions (so-called mole mapping),
patient education on skin self-examination (ABCDE rule: asymmetry, border, color, diameter, evolution).

Particular attention should be paid to lesions showing:

rapid growth,
change in color or structure,
the appearance of subjective symptoms (itching, burning, bleeding).

2. Surgical treatment

Indications for the removal of Clark's nevus include:

suspicion of neoplastic transformation,
significant atypia in dermoscopic examination,
difficulty in differentiating from melanoma,
location exposed to chronic irritation.

The standard of procedure is:

surgical excision of the lesion with a margin of healthy tissue,
performing a histopathological examination, which allows for the final diagnosis.

It should be emphasized that destructive methods (e.g., laser, electrocoagulation) do not constitute appropriate management for suspicious nevi, as they prevent histopathological assessment.

3. Importance of prevention

A key element of management remains prevention, including:

sun protection (SPF 50+ filters, avoiding UV exposure),
elimination of tanning beds,
control of risk factors (skin phototype, family history).

4. Procedures supporting diagnostics and aesthetics

In the practice of aesthetic medicine and dermatology, procedures supporting the assessment and improvement of skin condition are used; however, in the case of Clark's nevi, they are supplementary:

digital videodermoscopy – precise diagnostics and monitoring of lesions,
dermatological laser therapy – used exclusively for clearly benign lesions,
surgical removal of skin lesions – the standard in cases of suspected atypia.

The offer of modern dermatological and aesthetic medicine clinics also includes procedures that improve skin quality and allow for better assessment of lesions, such as:

regenerative treatments (e.g., mesotherapy, stimulating therapies),
advanced skin diagnostics.