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PubMed2001

[Large melanocytic nevi in generalized atrophic benign epidermolysis bullosa (epidermolysis bullosa nevi)].

Generalized atrophic benign epidermolysis bullosa (GABEB) is a nonlethal form of junctional epidermolysis bullosa. The expression of type XVII collagen (180 kDa bullous pemphigoid antigen) or of laminin 5 is markedly reduced in the skin. A 13-year-old patient with GABEB, developed several large, asymmetric, irregularly pigmented melanocytic nevi with poorly defined borders. They had appeared following blister formation since 8 years of age. Histological examination revealed an irregular proliferation of monomorphous melanocytes at the dermoepidermal junction. Small nests of melanocytes were focally present. This case further emphasizes the difficulty in differentiating nevi appearing in GABEB from malignant melanoma.

Adolescent↗
PubMed2001

Alterations of mismatch repair protein expression in benign melanocytic nevi, melanocytic dysplastic nevi, and cutaneous malignant melanomas.

Immunoperoxidase-staining methods were used to examine the expression of hMLH1, hMSH2, and hMSH6 mismatch repair (MMR) proteins in 50 melanocytic lesions. Microsatellite instability (MSI), screened previously in these lesions by polymerase chain reaction-based microsatellite assay, showed low-level microsatellite instability (MSI-L) in 11 of 22 melanocytic dysplastic nevi (MDN) and two of nine primary cutaneous malignant melanomas (CMMs) but not in the benign melanocytic nevi (BN). Mismatch repair proteins were widely expressed in the epidermis and adnexal structures. All lesions showed positive immunoreactivity with a gradual decrease in the MMR staining values during the progression from BN to MDN to CMMs. The average percentage of positively (PP) stained cells for hMLH1, hMSH2, and hMSH6 in BN was 85.50 +/- 1.95, 77.90 +/- 4.50, and 87.11 +/- 1.85, respectively. The PP cell values in CMMs were significantly reduced as compared with BN (75.22 +/- 3.57, p= 0.01; 56.11 +/- 8.73, p= 0.02; 65.22 +/- 6.47, p = 0.0002 for hMLH1, hMSH2, and hMSH6, respectively). No comparable significant difference was found between microsatellite stable and MSI-L lesions (p = 0.173, p = 0.458, and p = 0.385), suggesting a lack of correlation between MMR expression and MMR function. There was a direct correlation between PP cell values of hMSH2 and hMSH6 (R = 0.39, p = 0.008), implying that their expression could be regulated by a common mechanism. Thus, an important finding of these studies was the reduction of MMR protein levels in CMMs; whether this reflects underlying genetic or epigenetic mechanisms is still to be determined.

Adaptor Proteins, Signal Transducing↗
PubMed1992

Familial multiple lateral telangiectatic nevi (port-wine stains or nevi flammei).

Two families with multiple lateral telangiectatic nevi (LTN) (port-wine stains or nevi flammei) in various areas of the body in two and three generations are presented. In the second family, some members in addition to LTN also had superficial (strawberry) hemangiomas and hemangioma-like venous malformations. The pedigrees of these families indicate autosomal dominant inheritance of multiple LTN.

Adult↗
PubMed1997

Mode of c-myc protein expression in Spitz nevi, common melanocytic nevi and malignant melanomas.

The expression of c-myc protein was studied in formalin-fixed, paraffin-embedded sections of 16 compound Spitz nevi (SNs), 20 ordinary compound melanocytic nevi (MNs) and 30 malignant melanomas (MMs), using monoclonal antibody 9E10 and an immunoperoxidase technique. Nine (56%) SNs, 16 (80%) MNs and 23 (77%) MMs showed positive reactions in some of the tumor cells (P = non-significant). The staining reactions were mostly cytoplasmic, and moderate to strong in intensity. The frequencies of positively stained cells were higher in the MN and SN groups. Most of the lesions with a significant dermal component did not show stratification of staining with progressive descent into the dermis. Therefore, the mode of expression of c-myc in routinely processed specimens does not differentiate between SNs, MNs and MMs. One possible reason is that the increased expression of the c-myc protein is not sufficient alone to promote proliferation and malignant transformation in these types of tumors.

Gene Expression↗
PubMed2000

A comparative immunohistochemical study of MART-1 expression in Spitz nevi, ordinary melanocytic nevi, and malignant melanomas.

BACKGROUND: The histopathologic differential diagnosis of Spitz nevus (SN) from malignant melanoma (MM) may be difficult. OBJECTIVE: We attempted to elucidate the pattern of expression of a newly recognized melanocyte-specific melanosomal protein MART-1 in routinely processed specimens of SNs, MMs, and ordinary melanocytic nevi (MNs) and to see whether it can help to differentiate between them. METHODS: Twenty SN, 22 MM, and 27 ordinary MN were immunostained with anti-MART-1 monoclonal antibody (clone A103). RESULTS: All SNs, MNs, and MMs demonstrated cytoplasmic staining for MART-1 in some of their tumor cells, of which 17 of 20 (85%) and 24 of 27 (89%) of SN and MN, respectively, demonstrated positive stainings in more than half of their tumor cells, as compared with only 10 of 22 (45%) of the MM (P <.05). The majority of lesions in all 3 types of tumors showed a homogeneous mode of staining, although MM tended to show a more heterogeneous pattern. A consistent pattern of stratification of staining with progressive descent into the dermis was not demonstrated in these tumors. CONCLUSION: MART-1 does not differentiate between SN, MM, and ordinary MN in a consistent pattern, but it may be used as a marker for these tumors.

Antigens, Neoplasm↗
PubMed2002

Loss of heterozygosity analysis of cutaneous melanoma and benign melanocytic nevi: laser capture microdissection demonstrates clonal genetic changes in acquired nevocellular nevi.

The molecular pathology of the common nevocellular nevus (NCN) and its relationship to the genetic model of malignant melanoma (MM) progression has not been fully characterized. We used laser capture microdissection of archival formalin-fixed material to study 34 melanocytic lesions (19 MM and 15 NCN). Twelve of the 15 NCN were acquired, 3 of which were congenital; none had dysplastic features. Ten polymorphic markers on five chromosomal regions (1p36, 6q22-23.3, 8p22-24, 10q23, and 11q23) were selected for loss of heterozygosity (LOH) analysis, based on previous studies demonstrating involvement in MM pathogenesis and progression. Loss of heterozygosity at any allelic locus was observed in 18 of 19 (95%) MM and in 9 of 15 (60%) NCN. Of the three congenital nevi analyzed, none showed LOH at any informative locus. The frequency of allelic loss was highest in the MM at 6q22-23.3 (64%), followed by 10q23 (62%), 8p22-24 (43%), 11q23 (43%), and 1p36 (13%). In the 15 NCN, the most frequent allelic losses were detected at 6q22-23.3 (29%), 1p36 (27%), and 10q23 (25%), with lower frequencies of LOH at 11q23 (10%) and 8p22-24 (7%). LOH at a single polymorphic marker, D6S1038, was detected in 70% of the MM and in 36% of the NCN, suggesting the presence of putative tumor-suppressor genes (TSGs) critical in melanocytic neoplasia at 6q22-23.3. The presence of clonal genetic alterations in acquired NCN justifies their classification as a benign neoplasm. The pattern of LOH in NCN is not random; rather, the relative frequencies of LOH at the chromosomal regions examined are consistent with a multistep model of MM progression that begins with NCN. Molecular analysis of NCN reiterates established epidemiologic and morphologic notions that NCN are precursor lesions for MM.

Adult↗
PubMed1996

Multivariate DNA cytometry discriminates between Spitz nevi and malignant melanomas because large polymorphic nuclei in Spitz nevi are not aneuploid.

To elucidate the reasons for the malignant histologic appearance of melanocytic nuclei within benign Spitz nevi (SN), we evaluated nuclear DNA distribution and nuclear size using a computerized image analysis system. In each case of 28 SN and 34 malignant melanomas (MM), about 100 randomly sampled nuclei were analyzed, prepared as monolayers from paraffin-embedded tissues. Large nuclei in MM (nuclear area > mean nuclear area of normal melanocytes + 4 delta) were significantly more likely to be aneuploid (DNA content > or = 5c) than large nuclei in SN chi2 test, p < 0.0001). Only two of 990 large SN nuclei exhibited DNA values higher than 5c, whereas 236 of 2,024 large MM nuclei were aneuploid or polyploid. Accordingly, in multivariate analysis, five features of DNA distribution proved to be most important for objective discrimination between MM and SN: 2c deviation index, 5c exceeding rate, standard deviation of the nuclear DNA content, and both the 85th and the 95th percentiles of DNA distributions. On the basis of these features, we could define a linear discriminant function that allowed a correct diagnosis in 94% of the cases. Our data demonstrate that diagnostically misleading large nuclei in SN are euploid, in contrast to MM. It is thus possible to discriminate SN and MM with high accuracy using DNA cytometry. Because paraffin-embedded tissue can be used, this technique could be a valuable complement to routine histology in equivocal cases.

Algorithms↗
PubMed2004

Variability in nomenclature used for nevi with architectural disorder and cytologic atypia (microscopically dysplastic nevi) by dermatologists and dermatopathologists.

BACKGROUND: Although a nevus with the microscopic features of a "dysplastic nevus" is commonly seen, the nomenclature used to describe such a lesion has been thought to be inconsistent. A 1992 National Institutes of Health (NIH) Consensus Conference sought to unify nomenclature and suggested that the term "nevus with architectural disorder" be used along with a comment on melanocytic atypia. METHODS: We performed a cross-sectional mail survey to determine preferred terminology as well as the level of adherence to the NIH-recommended nomenclature. All 856 active members of the American Society of Dermatopathology (ASDP) and 1100 (13.0%) of the 8471 active members of the American Academy of Dermatology (AAD) were surveyed. RESULTS: Five hundred and thirty-three ASDP members and 483 AAD members who fulfilled eligibility criteria completed the questionnaire. The term "dysplastic nevus" was favored by the largest number of responders (favored by 39.1% of ASDP members and 62.3% of AAD members), while the 1992 NIH Consensus Conference-recommended terminology was the second most popular term (25.3% of ASDP and 15.1% of AAD members). Dermatopathologists (OR = 1.9, p = 0.0001) and those who had dual training in dermatology and dermatopathology (OR = 1.6, p = 0.02 for ASDP members; OR = 2.3, p = 0.02 for AAD members) were more likely to adhere to the 1992 NIH Consensus Conference nomenclature. CONCLUSIONS: Despite attempts to unify nomenclature for microscopically dysplastic nevi through the NIH Consensus Conference, wide variation in terminology persists.

Consensus Statements as Topic↗
PubMed1990

A hypothesis incorporating the histologic characteristics of dysplastic nevi into the normal biological development of melanocytic nevi.

A lentiginous pattern of intraepidermal melanocytic hyperplasia, with mild to moderate, random cytologic atypia, forms the conventional basis for the histologic definition of a dysplastic nevus. It is proposed here that these changes actually represent the histologic pattern of a nevus in an active phase of radial growth. The lesser degrees of atypia considered by others to be required for the diagnosis are suggested to overlap changes commonly seen in banal nevi and lentigines. This hypothesis allows the parsimonious concept that a nevus, originating as a lentigo, can at the later sequential junctional, compound, or intradermal stages expand peripherally by a resumption or persistence of the lentiginous pattern of proliferation. The random atypia that is seen in such lesions is suggested to be incidental to the proliferative process rather than indicative of dysplasia as conventionally defined. A familial melanoma-associated phenotype could be accommodated in this model by postulating a heritable defect in mechanisms that control the number or sizes of these hyperplastic lesions.

Dysplastic Nevus Syndrome↗
PubMed1979

Birthmarks with serious medical significance: nevocullular nevi, sebaceous nevi, and multiple café au lait spots.

Birthmarks of potential medical significance were identified among 4,641 newborn infants: 1.1% had a nevocellular nevus and 0.3% had a sebaceous nevus; 1.8% of black infants, but no white infants, had three or more café au lait spots. The large nevocellular nevus is considered premalignant, but the significance of the small nevocellular nevus has not been established. The sebaceous nevus fades after birth but undergoes hyperplasia at puberty. Multiple café au lait spots occur less commonly in white than in black infants, and are therefore of greater concern as possibly an early sign of neurofibromatosis.

Child, Preschool↗