Types Of Naevi Research Articles

Spotted grouped pigmented naevus type I.

Spotted grouped pigmented naevus type I.

Congenital Naevus: Case Report of an Atypical Atrial Location

Congenital naevi are a benign proliferation of melanocytes. Present at birth or appearing in the first weeks of life, they have the appearance of light to dark brown lesions, sometimes bluish, more or less hairy. It is a non-hereditary mosaic pathology. They are due to postzygotic somatic mutations involving key proteins in the mitogen-activated protein kinase pathway, mainly NRAS and BRAF. Its prevalence is estimated to be between 1 and 3% of newborns. This disease can affect any part of the skin. There are 3 types of naevi: small, medium and large naevi then called giant. The objective was to discuss the clinical and therapeutic aspect of a congenital auricular naevus of medium size. We report the case of an 18 years old girl presenting a sessile tumefaction at the level of the concha of the right auricle that appeared from birth, firm, rough, unique, about 5 cm in diameter, homogeneous in color, pigmented, hairy, painless to palpation, apyretic sometimes pruritic without any other associated sign. The diagnosis of benign congenital naevus was clinically made after confirmation by the dermatologist. Surgical removal was performed. The postoperative course was simple with complete healing after one month. The middle congenital naevus is a benign tumor linked to a genetic variation of low incidence, which is all the more rare as it is located on the ear, thus having a significant psychological impact due to its often unsightly appearance. The diagnosis of this genodermatosis is essentially clinical. When it is an isolated nodule, as in our study, total surgical removal is a good alternative with simple after-effects and an almost non-existent risk of malignant transformation.

Segmental hypomelanosis and hypermelanosis arranged in a checkerboard pattern are distinct naevi: flag-like hypomelanotic naevus and flag-like hypermelanotic naevus.

The categorization of congenital hypo- or hyperpigmented skin lesions following a segmental pattern has been a long-lasting matter of debate and have been reported under various and often incorrect terms. To reassess published hypomelanotic and hypermelanotic lesions that did not follow Blaschko lines nor a phylloid pattern of mosaicism, we carried out an extensive and critical review of the worldwide literature. Seventy-four retrieved cases consisted of lateralized hypomelanotic lesions arranged in a flag-like pattern or appearing as large patches of grossly oval or angulated shape and sharp, serrated margins. Sometimes lesions harboured maculopapular melanocytic naevi or cooccurred with other segmentally arranged naevi. A probably non-random association with extracutaneous anomalies was also reported on rare occasions. In 70 cases, lateralized hypermelanotic patches were arranged in a flag-like pattern that often appeared as large quadrangular patches. Sometimes lesions harboured Spitz naevi. Ten cases belonged to phacomatosis melanorosea, whereas several others were part of so far uncategorized cases of phacomatosis pigmentovascularis. Flag-like hypomelanosis is a distinct naevus type, for which the term 'flag-like hypomelanotic naevus' is suggested. Its cooccurrence with extracutaneous abnormalities might represent a specific syndrome. Flag-like hypermelanosis is a distinct naevus type, for which the term 'flag-like hypermelanotic naevus' is suggested. Its co-occurrence with naevus roseus defines phacomatosis melanorosea. Flag-like hypermelanotic naevus should be distinguished from the checkerboard-like areas of darker skin as observed in chimaeras.

Clinical and dermoscopic characteristics of new naevi in adults: results from a cohort study

Naevogenesis is a process known to occur throughout life. To date, investigators have made conclusions about new naevi in adults based on results of cross-sectional studies. To determine the incidence of new naevus development in adults and to describe the dermoscopic morphology of new naevi. A cohort of 182 patients seen at the outpatient dermatology clinic at Memorial Sloan-Kettering Cancer Center between 2000 and 2009 was evaluated with baseline total body photographs. The patients were aged 17years or older and had presented for routine follow-up surveillance examination at least 3months after baseline total body photographs. The number of new naevi and the dermoscopic morphology of these naevi were recorded. Of the 182 patients evaluated, 50 (27%) developed at least one new naevus during follow-up. The incidence of new naevi was 202 per 1000 person-years of follow-up. The most common types of naevi were reticular (47·1%), followed by the homogeneous (22·1%) and complex (reticuloglobular) patterns (15·4%). Our results provide support for the theory that there are two distinct pathways of naevogenesis, a dynamic process occurring throughout life. This study demonstrates that the predominant dermoscopic morphology of newly acquired naevi in adults is reticular.

Frequency, clinical and dermoscopic features of benign papillomatous melanocytic naevi (Unna type)

Most previous studies on melanocytic naevi have not distinguished between the different types of naevi, except for some studies trying to define atypical naevi. No large, population-based studies on papillomatous or Unna-type melanocytic naevi have been performed. To investigate the dermoscopic and clinical features of papillomatous naevi and to study some of the factors which could potentially influence their development. Seven hundred and seven caucasians aged 1-82 years participated in a screening campaign at open-air recreation facilities in Austria. The volunteers underwent a total body examination by experienced dermatologists and answered a questionnaire. Clinical and dermoscopic images of one representative papillomatous naevus per person were taken. Twenty-nine per cent of the volunteers exhibited papillomatous naevi, the highest frequency being found in young adults. No correlation between the frequency of papillomatous naevi and gender, skin type, sunburns, sunbed use or hormonal factors was found. Most lesions were brown papules (median diameter 5.0 mm), located on the trunk. Dermoscopy showed a predominance of homogeneous and globular pattern, multifocal hypo/hyperpigmentation and comma vessels. Of the papillomatous naevi, 9.8% showed suspicious scores with dermoscopic algorithms. The lack of exogenous influencing factors and the predominance of globular dermoscopic pattern strengthen the hypothesis that papillomatous naevi belong to the same spectrum as small congenital melanocytic naevi. As the role of papillomatous naevi as precursors of melanoma remains unclear and they are frequently not recognized by the patients, one should perform dermoscopy of papillomatous naevi during skin cancer screening.

Viewpoint 2

Viewpoint 2

Clinical selection of melanocytic lesions for dermoscopy decreases the identification of suspicious lesions in comparison with dermoscopy without clinical preselection

In most cases dermoscopy is performed only on lesions selected by clinical inspection which present worrying clinical features or appear to deviate from the patient's average type of naevus. Thus, possible early malignant melanomas (MMs) or MM precursors, lacking typical clinical characteristics, may elude the dermoscopic examination. To perform a comparison between two different approaches to the patient's examination, one based on a clinical preselection of lesions to be examined by dermoscopy, and the other consisting of the dermoscopic scrutiny of all melanocytic lesions with a diameter>or=2 mm (total dermoscopy). Sixty-three consecutive patients with MM, undergoing periodic dermoscopic examinations of their naevi, were enrolled in the study. The patients first underwent an assessment of the entire skin with the unaided eye for the identification of lesions for dermoscopy. Subsequently, the patients underwent dermoscopic examination of all melanocytic lesions. Images of naevi identified by clinical examination or by total dermoscopy as having dermoscopic aspects characteristic of a suspicious lesion, i.e. necessitating either surgical excision or follow-up examinations, were separately recorded, classified and described employing the ABCD rule of dermoscopy and the seven-point checklist. Five hundred and fifty-one lesions were chosen by clinical inspection for subsequent dermoscopic examination; among these, 117 were considered for excision or follow-up. Ninety-two further lesions were identified for excision or follow-up by employing only total dermoscopy. Dermoscopy scores of lesions selected by clinical inspection plus dermoscopy were similar to those identified by dermoscopy alone. In the former group, 13 lesions showed either an ABCD or a seven-point score corresponding to a suspicious lesion, whereas eight such lesions were identified only by total dermoscopy. Thus, by clinical selection plus dermoscopy we were able to identify only 62% of dermoscopically suspicious lesions. Clinical selection of melanocytic lesions for dermoscopic examination is associated with the 'loss' of a conspicuous number of lesions which deserve surgical excision or follow-up examinations. Total dermoscopy, enabling the detection of suspicious lesions, together with storage, retrieval and sequential comparison of their images, could enhance MM diagnosis by follow-up, in comparison with clinical preselection for dermoscopy.

Instrument-, age- and site-dependent variations of dermoscopic patterns of congenital melanocytic naevi: a multicentre study

Recently, we identified and described dermoscopic aspects, present with a higher frequency in congenital melanocytic lesions with respect to acquired naevi. We also classified small- and medium-sized congenital naevi (CN) into nine subtypes according to their macroscopic and dermoscopic aspects. Because the recognition of dermoscopic features may be instrument dependent, in this study, we wanted to check whether dermoscopic patterns specific for CN can be identified in digital images acquired by means of different instruments. We also wanted to check the validity of our previously proposed classification and assess possible age- and site-dependent variations of dermoscopic patterns and naevus subtypes. Images corresponding to 384 small- or medium-sized CN were collected in eight different centres employing four different instruments. Lesion images were evaluated and checked for the presence of specific dermoscopic criteria, classified, and compared with a database of 350 acquired naevi. Specific and unspecific dermoscopic features were identifiable in images acquired by means of all four instrument types. The mean number of identified features per lesion did not vary according to the instrument employed for the acquisition of the images; however, it was lower for lesions recorded employing low magnifications. The previously proposed classification was easily applied to the whole image database. The variegated naevus type was identified as a highly specific clinical/dermoscopic pattern. Dermoscopic features varied according to age and location. The globular type prevailed in subjects under 11 years of age and on the trunk, whereas the majority of reticular lesions were located on the limbs. Because definite clinical and histological criteria for the diagnosis of the congenital nature of naevi are lacking, the use of dermoscopy can be of great help in identifying those lesions where the presence of specific dermoscopic features makes the diagnosis of CN more likely. Moreover, dermoscopy can be useful both for the classification of lesions already identified as congenital according to definite clinical and anamnestic data and for a possible correlation of naevus phenotype and dermoscopic patterns to the risk of developing a malignant melanoma in prospective studies.

Combined naevus: a benign lesion frequently misdiagnosed both clinically and pathologically as melanoma

Combined naevi are characterised pathologically by the presence of two or more different types of melanocytic naevi in a single lesion. They are prone to clinical and pathological misdiagnosis as melanoma. Misdiagnosis may result in inappropriate treatment, patient anxiety and medicolegal consequences. With the aim of reducing the incidence of misdiagnosis, this study documents the clinical and pathological features of a large series of combined naevi and describes how to distinguish them from melanoma. The slides of skin lesions from 220 patients that were coded as combined naevus between 1990 and 2001 were retrieved from the archival files of the Department of Anatomical Pathology, Royal Prince Alfred Hospital, Sydney, Australia. The clinical notes, letters from referring pathologists (for consultation cases) and slides were reviewed and for each lesion clinical and pathological features were assessed. Thirty-eight cases were excluded either because they included only one naevus component or because there were atypical pathological features in the slides available for review. The remaining 182 cases formed the study population. The patients included 92 females and 87 males (1.1:1). In three cases the gender was not known. Mean and median patient ages were 29.6 and 28 years, respectively. The anatomical site of involvement was the trunk in 64 cases (35.2%), head and neck region in 43 cases (23.6%), upper extremity in 40 cases (22.0%), lower extremity in 18 cases (9.9%) and perineum and buttock region in eight cases (4.4%). In nine cases the site of involvement was not known. A pre-operative clinical diagnosis was recorded in 126 cases; of these, melanoma was suspected clinically in 33 cases (26.2%) while combined naevus was diagnosed clinically in only three cases (2.4%). Histologically, 180 cases included two different naevus components, and in two cases three different naevus components were present. The most common combination was a common acquired naevus of compound type associated with a blue naevus of deep penetrating naevus type; this occurred in 57 cases (31.3%). The referring pathologist recorded a preferred diagnosis in 88 of 122 consultation cases; of these, melanoma was suspected in 23 cases (26.1%) and in 23 cases combined naevus was favoured (26.1%). Combined naevus is an uncommon type of melanocytic naevus that is frequently misdiagnosed both clinically and pathologically. Knowledge and recognition of the pathological features of combined naevi and the important features that distinguish them from melanomas should reduce the frequency of misdiagnosis.

Use of multiple cytometric markers improves discrimination between benign and malignant melanocytic lesions: a study of DNA microdensitometry, karyometry, argyrophilic staining of nucleolar organizer regions and MIB1-Ki67 immunoreactivity.

Confident separation of benign naevi and malignant melanoma can sometimes be very difficult using conventional microscopy. This study evaluated the combined diagnostic abilities of multiple cytometric markers in separating various types of naevi from melanomas. The lesions studied included 27 benign compound naevi, 20 dysplastic naevi, 10 Spitz naevi and 24 melanomas. The cytometric features investigated were: (i) nuclear DNA content and chromatin compactness, measured by video imaged DNA microdensitometry; (ii) nuclear morphology, measured by nuclear morphometry (karyometry); (iii) transcriptional activity of nucleolar organizer regions, measured as the number and size of argyrophilic staining of nucleolar organizer regions (AgNORs); and (iv) cellular proliferative activity detected by quantifying the immunoreactivity of MIB1-Ki67 antigen. These variables were evaluated in the superficial, middle and deep zones of each lesion. Using multivariate discriminant analysis, a total diagnostic effectiveness of 97% could be achieved in separating the benign and malignant melanocytic lesions by co-evaluating variables for DNA microdensitometry, karyometry and AgNORs. A diagnostic effectiveness of 100% could be achieved if further co-evaluation with MIB1-Ki67 immunoreactivity was performed. Our study suggests that co-evaluation of multiple cytometric markers can improve the diagnostic abilities of individual techniques in separating benign naevi from malignant melanomas. This may be of particular significance in the diagnosis of melanocytic lesions whose biological behaviour cannot be confidently predicted by their histological features using conventional microscopy.

Hormonal therapy of malignant melanoma

Combined naevi are characterised pathologically by the presence of two or more different types of melanocytic naevi in a single lesion. They are prone to clinical and pathological misdiagnosis as melanoma. Misdiagnosis may result in inappropriate treatment, patient anxiety and medicolegal consequences.With the aim of reducing the incidence of misdiagnosis, this study documents the clinical and pathological features of a large series of combined naevi and describes how to distinguish them from melanoma.The slides of skin lesions from 220 patients that were coded as combined naevus between 1990 and 2001 were retrieved from the archival files of the Department of Anatomical Pathology, Royal Prince Alfred Hospital, Sydney, Australia. The clinical notes, letters from referring pathologists (for consultation cases) and slides were reviewed and for each lesion clinical and pathological features were assessed. Thirty-eight cases were excluded either because they included only one naevus component or because there were atypical pathological features in the slides available for review. The remaining 182 cases formed the study population.The patients included 92 females and 87 males (1.1:1). In three cases the gender was not known. Mean and median patient ages were 29.6 and 28 years, respectively. The anatomical site of involvement was the trunk in 64 cases (35.2%), head and neck region in 43 cases (23.6%), upper extremity in 40 cases (22.0%), lower extremity in 18 cases (9.9%) and perineum and buttock region in eight cases (4.4%). In nine cases the site of involvement was not known. A pre-operative clinical diagnosis was recorded in 126 cases; of these, melanoma was suspected clinically in 33 cases (26.2%) while combined naevus was diagnosed clinically in only three cases (2.4%). Histologically, 180 cases included two different naevus components, and in two cases three different naevus components were present. The most common combination was a common acquired naevus of compound type associated with a blue naevus of deep penetrating naevus type; this occurred in 57 cases (31.3%). The referring pathologist recorded a preferred diagnosis in 88 of 122 consultation cases; of these, melanoma was suspected in 23 cases (26.1%) and in 23 cases combined naevus was favoured (26.1%).Combined naevus is an uncommon type of melanocytic naevus that is frequently misdiagnosed both clinically and pathologically. Knowledge and recognition of the pathological features of combined naevi and the important features that distinguish them from melanomas should reduce the frequency of misdiagnosis.

Proliferative activity of cutaneous melanocytic neoplasms defined by a proliferating cell nuclear antigen labelling index.

To evaluate the proliferative activity of benign, borderline and malignant cutaneous melanocytic neoplasms, 30 cases of malignant melanoma (MM) and 41 cases of naevi were studied by immunostaining using a monoclonal antibody against proliferating cell nuclear antigen (PCNA). PCNA is a nuclear antigen expressed in the late G1 and S phase and serves as a marker of proliferating cells. Invasive MM and MM in situ showed much higher PCNA positivity rates than melanocytic naevi (invasive MM, 18.0%; MM in situ, 11.3%; ordinary melanocytic naevi, 2.6%). The PCNA positivity rate did not increase significantly with the thickness of MM. Among ordinary melanocytic naevi, junctional naevi had a higher PCNA positivity rate than compound or intradermal naevi. Mean PCNA positivity rates for Spitz's naevi and sporadic dysplastic naevi were within the range for ordinary melanocytic naevi, indicating the benign nature of both types of naevus. Contrary to some previous studies, MM in situ showed high proliferative activity, indicating that cells of MM in situ are actively proliferating. This study clearly demonstrates that MM and various types of naevi can be separated according to differences in proliferative activity defined by the PCNA labeling index.

An assessment of the value of Ag NOR staining in the identification of dysplastic and other borderline melanocytic naevi

One hundred and six melanocytic lesions were studied to determine the value of the so called Ag NOR technique in differentiating dysplastic naevi, Spitz naevi and spindle cell naevi of Reed from malignant melanoma and from 'banal' compound or intradermal naevi. In 79 cases Ag NOR counts were possible. The banal naevi (36) had a mean count of 1.54, (SD 0.3), and the unequivocally malignant superficial spreading melanomas (13), lentigo maligna melanomas (4) and secondary melanomas (4) had a mean count overall of 3.9 (SD 1.59). For dysplastic naevi (16) the mean Ag NOR count was 1.63 (SD 0.36) and for Spitz and spindle cell naevi (in toto 6) the figure was 1.72 (SD 0.55). The difference in Ag NOR counts between all types of naevi and all types of melanoma was highly statistically significant, but there was no difference between banal naevi and dysplastic, Spitz, and spindle cell naevi. Correlation of Ag NOR counts between three independent observers was good. This technique may, therefore, be a useful adjunct in separating true melanoma from borderline melanocytic naevi.

Naevus fusco-caeruleus zygomaticus.

One hundred and ten cases of an unusual type of naevus, which we have called naevus fusco-caeruleus zygomaticus were studied. The naevus presents as a bilateral speckled discolouration of the skin of the face principally in the zygomatic region. The condition usually does not become apparent until the second decade of life, and is much commoner in females. No association with any other abnormalities was found. Light and electron microscopy of the speckles showed the presence of dermal melanocytes mostly in the upper dermis. A survey was also carried out to determine the prevalence of this naevus in the general population.

Relative increase of Langerhans cells in 'banal' and dysplastic melanocytic naevi.

Langerhans cell counts were carried out in 16 normal or banal melanocytic naevi and 22 dysplastic naevi, and the numbers in the naevi compared with Langerhans cell numbers in perilesional, clinically normal, epidermis. Langerhans cell numbers were found to be raised in both types of naevi, but no significant difference between Langerhans cell numbers in the two types of naevi was found.

Variations in S-100 protein expression in naevocellular naevi may be related to metabolic activity.

Significant amounts of S-100 protein were demonstrated in naevus cells by an immunoperoxidase technique. Distribution of S-100 protein was similar in the various types of naevi tested. In most lesions, the superficial A-type naevus cells stained most heavily, while staining was weaker in the deeper B- and C-type naevus cells. The intensity of staining was not, however, homogeneous in the cells of the various layers of the naevus. S-100 protein was especially abundant in giant naevus cells which occurred in the vicinity of sub-epidermal A-type naevocytes. Cells from neurocutaneous melanosis contained extremely large amounts of S-100 protein. Normal melanocytes in the epidermis over dermal naevi contained variable amounts of S-100 protein, but mainly showed weak staining. However, in the basal epidermis of traumatized naevi there were many unusually large and partly dendritic melanocytes. In this part of the epidermis, S-100 protein-positive cells lay close together, and many stained strongly. In earlier work, large amounts of metabolic enzymes were found at the same sites in traumatized naevi and giant cells. These results suggest that a high degree of expression of S-100 protein is due to metabolic activity shown, for example, by giant naevus cells and basal melanocytes of the regenerating epidermis over traumatized naevi.

Proposed alternative terminology and subclassification of so called "dysplastic naevi".

The term "dysplastic" melanocytic naevus has recently been used to describe pigmented naevi with unusual histological and clinical features. There is currently no clear clinical or pathological definition of the term, and this has led to a lack of comparability of material described in reports on these lesions. As a result of careful histological study and a clinicopathological correlation of 100 naevi, we suggest that three distinct groups of histopathological features distinguish so called dysplastic naevi from banal melanocytic naevi. These are architectural atypia, cytological atypia, and a host response. Description of each of these features in routine reports and in published series in place of the loose use of the term "dysplastic" would enable comparisons to be made between series of melanocytic lesions reported from different centres. In the course of this study we observed a considerably increased incidence of naevus type giant cells in the dermal portion of the atypical naevi. These giant cells should not be confused with possibly premalignant cytological atypia.