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Background: We tested the relevance of clinical information in the histopathologic evaluation of melanocytic skin neoplasm (MSN)., Methods: Histopathologic specimens from 99 clinically atypical MSN were circulated among ten histopathologists; each case had clinical information available in a database with a five-step procedure (no information; age/sex/location; clinical diagnosis; clinical image; dermoscopic image); each step had a histopathologic diagnosis (D1 through D5); each diagnostic step had a level of diagnostic confidence (LDC) ranging from 1 (no diagnostic certainty) to 5 (absolute diagnostic certainty). The comparison of the LDC was employed with an analysis of variance (ANOVA) for repeated measures., Findings: In D1 (no information), 36/99 cases (36.3%) had unanimous diagnosis; in D5 (full information available), 51/99 cases (51.5%) had unanimous diagnosis (p for difference between proportions <0.001). The observer agreement expressed as kappa increased significantly from D1 to D5. The mean LDC linearly increased for each observer from D1 through D5 (p for linear trend <0.001). On average, each histopathologist changed his initial diagnosis in 7 cases (range: 2-23). Most diagnostic changes were in D2 (age/sex/location)., Interpretation: The histopathologic criteria for the diagnosis of MSN can work as such, but the final histopathologic diagnosis is a clinically-aided interpretation. Clinical data sometimes reverse the initial histopathologic evaluation.

The efficacy of the histological criteria currently used in the diagnosis of melanoma is still to be defined. We performed a quantitative analysis of 72 conventional (non-Spitzoid, nondesmoplastic) melanomas and 73 conventional melanocytic naevi, used as controls, for 13 histological diagnostic parameters (dimension >6 mm, asymmetry, poor circumscription, irregular and confluent nests, single melanocytes predominating, absence of maturation, suprabasal melanocytes, asymmetrical melanin, melanin in deep cells, cytological atypia, mitoses, necrosis and dermal lymphocytic infiltrate). Differences in the distribution of selected parameters between the two groups were investigated by Fisher's exact test; for each parameter sensitivity and specificity were calculated. Results showed that all parameters, except poor circumscription, seemed to be significantly associated with melanoma (P<0.05). Cytological atypia, dermal lymphocytic infiltrate, asymmetry, dimension >6 mm and absence of maturation showed a high sensitivity (>90%); absence of maturation, mitoses, necrosis, asymmetrical melanin, suprabasal melanocytes and melanin in deep cells showed a high specificity (>90%); irregular-confluent nests and single melanocytes predominating were poorly sensitive and poorly specific. In melanomas < or =2 mm, two additional parameters were sensitive (> or =90%): suprabasal melanocytes and single melanocytes predominating. We conclude that not all parameters showed to have the same diagnostic value. Absence of maturation and, limited to melanomas < or =2 mm, suprabasal melanocytes were the most discriminating (sensitive and specific) histological features. Cytological atypia, dimension >6 mm, suprabasal melanocytes and mitoses were additional reliable diagnostic features, showing a relatively high sensitivity and a relatively high specificity. Other useful features were dermal lymphocytic infiltrate and asymmetry (sensitive) and necrosis, asymmetrical melanin and melanin in deep cells (specific).

Most nodal nevi are intracapsular and present the morphology of conventional nevi; less frequently, they show the appearance of common and cellular blue nevi. We report a case of an nodal capsular, trabecular and intraparenchymal melanocytic nevus with balloon-cell change in a patient with a malignant melanoma which arose in a pre-existing cutaneous giant congenital nevus, showing balloon-cell degeneration.

Background: Melanocytic nevi in the genital, acral, and flexural sites often display clinical and histologic features that may simulate melanoma. We verified whether this is the case also for nevi of the breast., Methods: Eleven dermatopathologists, from nine Italian Institutions, collected the specimens of melanocytic lesions from the breast and other body sites, excluding the acral, genital, and flexural areas, as controls. Cases and controls were matched for sex and age. All nevi were observed 'blindly' and simultaneously by all participants. For each lesion, 10 histological parameters were analyzed: asymmetry, absence of lateral demarcation of melanocytes, lentiginous proliferation, nested and dyshesive pattern, intraepidermal melanocytes above the basal layer, involvement of the hair follicle, absence of maturation of dermal melanocytes, melanocytic atypia, fibroplasia of the papillary dermis, and lymphocytic dermal infiltrate. Each parameter was scored 2 when present and 1 when absent or not valuable. A total score was calculated for each lesion. Results were statistically analyzed by the chi-square test and the Mann-Whitney U-test., Results: One hundred and one nevi came from the breast area and 97 from elsewhere. Breast nevi exhibited significantly more atypical features than nevi from other sites. In particular, breast nevi with intraepidermal melanocytes, melanocytic atypia, and dermal fibroplasia were significantly more numerous. We did not find any sexual difference., Conclusions: To avoid undue concerns, dermatopathologists should be aware that melanocytic nevi of the breast may show a high degree of atypical features.

The 3H-thymidine labelling (LI) and mitotic (MI) indexes were calculated in 29 cutaneous melanocytic lesions: 6 common nevi (CN), 11 dysplastic nevi, subclassified as nevi with architectural atypia (NAA = 4) and nevi with cyto-architectural atypia (NCAA = 7), 2 melanomas in situ (MIS), 4 invasive superficial spreading melanomas (IM) and 6 metastatic melanomas (MM). The LI mean values resulted to be: CN = 0.23%, NAA = 0.98%, NCAA = 1.79%, MIS = 5.75%, IM = 5.16%, MM = 3.80%. In CN, NAA, NCAA and MIS, these values were calculated at epidermal level; in IM and MM at dermal level. At dermal level, the LI mean values of CN, NAA and NCAA were: 0.20%, 0.20%, 0.23% respectively. The MI mean value was close to 0 in CN, NAA, NCAA, MIS; 0.18% in IM, 0.16% in MM. Confirming a low proliferative activity in CN and a high activity in melanomas (MIS, IM, MM), the results showed that dysplastic nevi (NAA, NCAA) had a proliferative activity intermediate between common nevi and melanomas. The lesions with melanocytic atypia (NCAA) resulted to have a higher proliferative activity than those without this histological feature (NAA).

Fifty cutaneous pigmented lesions characterized by an intraepidermal proliferation of atypical melanocytes were reviewed. Several histological parameters (position of melanocytes in the epidermis, nuclear melanocytic atypia, presence or absence of pagetoid melanocytes, nucleoli, and others) were evaluated. On the basis of the results, the investigated cases were classified into three groups. In group 1, pagetoid melanocytes were present, melanocytic atypia was severe and continuous, all epidermal layers were involved by melanocytic proliferation, and a pattern of epidermal infiltration was recognized. In group 2, pagetoid melanocytes were absent, melanocytic atypia was mild-moderate and discontinuous, the lower epidermis only was involved by melanocytic proliferation, and a pattern of epidermal pseudoinfiltration was recognized. Group 3 cases were in an intermediate area between the two major groups. The results showed that intraepidermal proliferations of atypical melanocytes lie on one line, in which groups 1 and 2 account for the extremes.

Histological analysis of intraepidermal melanocytic proliferation in the peripheral areas of superficial spreading melanoma. The intraepidermal melanocytic proliferation in the areas adjacent to the invasive component of 100 superficial spreading melanomas of the skin (levels III and IV) was studied. Three patterns were identified: 1) melanoma in situ type (MIS); 2) melanocytic dysplasia type (DYS); 3) normal skin or increased number of typical melanocytes (0). The different distribution of these patterns in the areas adjacent to the invasive melanoma led to a histological classification of the tumors into 4 topographical models. Two models showed MIS areas and contiguous normal skin (A1, A2); two models showed MIS areas adjacent to DYS areas, that in turn were contiguous to normal skin (B1, B2). In all cases, however, in centrifugal sense, more severe alterations preceded less severe ones. These observations suggest that superficial spreading melanoma grows horizontally by induction of neighbour cells (neoplastic recruitment). The neoplastic transformation seems to progress in two ways: directly to melanoma in situ or through an intermediate phase (melanocytic dysplasia).

Nuclei of melanocytes in 10 common acquired melanocytic nevi, 10 malignant melanomas and 10 dysplastic melanocytic nevi (melanocytic dysplasia) (MD) were morphometrically analyzed. MD group consisted of 6 lesions with (MD 1) and 4 without (MD 2) the clinical features of dysplastic nevi. The considered parameters were area, perimeter and form Ar. In the MD group, the results showed that median values of each considered parameter of MD 1 were close to those of MD 2. For each evaluated parameter, median values of MD turned out to be intermediate between those of common acquired melanocytic nevi and of malignant melanomas. Confirming the histologic evidence of a double - nonatypical and atypical - melanocytic population in melanocytic dysplasia, our data showed that nonatypical melanocytes were indistinguishable from melanocytes of common acquired nevi, while the atypical melanocytes were close to melanoma cells. The importance of atypical melanocytes is stressed in the diagnosis of melanocytic dysplasia.

Nuclei of melanocytes in 10 lentigines simplices, 10 junctional, 10 compound and 10 intradermal acquired melanocytic nevi were morphometrically evaluated, at three different skin levels: epidermis, papillary and reticular dermis. The considered parameters were: area, perimeter, form Ar, and form Ell. Mean values of nuclear area and form Ell demonstrated a progressive increase from lentigines to junctional to compound to dermal nevi. This trend was also observed for each considered level. In compound nevi mean values of nuclear area showed an increase from the epidermis to the papillary dermis. In compound and intradermal nevi they showed a decrease from the papillary to the reticular dermis. Mean values of nuclear form Ell presented a continuous increase from the epidermis to the papillary and reticular dermis. Our study shows that, in the evolution of the considered melanocytic lesions (from lentigo to dermal nevi), the nuclei of melanocytes become larger and rounder. In compound nevi, epidermal nuclei were smaller and more elongated than those of the papillary dermis. In compound and intradermal nevi, superficial dermal nuclei appeared larger but less round than the deep ones. These peculiar findings have been generally referred to as a melanocytic maturation process. They are also probably due to other factors, perhaps local factors, because a similar trend is observed in some malignant melanomas.

Aims: To assess the interobserver reproducibility of certain histological features proposed for the diagnosis of melanoma. Methods: In a series of melanomas, 13 histological parameters were analysed: dimension > 6 mm, asymmetry, poor circumscription, irregular confluent nests, single melanocytes predominating, absence of maturation, suprabasal melanocytes, asymmetrical melanin, melanin in deep cells, cytological atypia, mitoses, dermal lymphocytic infiltrate, and necrosis. Results: The agreement (reproducibility) between the nine observers was excellent (κ > 0.75) for 10 of the 13 examined features (dimension > 6 mm, poor circumscription, irregular confluent nests, single melanocytes predominating, absence of maturation, suprabasal melanocytes, asymmetrical melanin, melanin in deep cells, mitoses, and necrosis). The agreement for asymmetry was very close to excellence (κ = 0.74), and that for cytological atypia (κ = 0.65) and dermal lymphocytic infiltrate (κ = 0.47) was slightly lower, but in the fair to good agreement range. The κ values obtained by comparison with the majority diagnosis were generally high (⩾ 0.85); the mean value of κ was lower (0.70) for only one parameter (dermal lymphocytic infiltrate). Conclusions: The parameters investigated showed an overall good reproducibility. [ABSTRACT FROM AUTHOR]

Aims: The histological features used in the diagnosis of melanoma may be present in benign naevi, but quantitative data are not available. The aim of this study was to establish the real prevalence of such features in naevi. Methods: Ten dermatopathologists, from nine Italian institutions, studied a series of naevi. Eleven histological parameters currently used in melanoma diagnosis were analysed: asymmetry, poor circumscription, predominance of single melanocytes, irregular confluent nests, suprabasal melanocytes, hair follicle involvement, absence of maturation, cytological alypia, dermal lymphocytic infiltrate, mitoses, and necrosis. Results: Ninely one naevi were examined: 22 junctional, 59 compound, and 10 intradermal. None of the studied parameters was seen in 22 of the benign naevi studied. One or more investigated features were found in 69 naevi. Poor circumscription was found in 49 cases, single melanocytic predominating in 42, asymmetry in 41, irregular confluent nests in 16, cytological atypia in 14, suprabasal melanocytes in seven, and hair follicle involvement in seven; absence of maturation, mitoses and necrosis were not found. Conclusions: The histological features used for the histological diagnosis of melanoma are often present in benign melanocytic naevi. This suggests a critical, non-mechanical use of them in melanoma diagnosis. [ABSTRACT FROM AUTHOR]