[But...was there ever a Clark classification of melanomas?]. / Pero...hubo alguna vez una clasificación de Clark de los melanomas?

For the past 40 years, the Clark classification of cutaneous melanoma has been accepted and used by the vast majority of dermatologists and pathologists throughout the world. However,after careful rereading of the most relevant articles by Clark and his collaborators, we can affirm that the classification was only ever of passing validity. Today, the possible morphological differences between one case of cutaneous melanoma and another are of no proven prognostic implication. In addition, the morphological differences that can be found are much more closely related to the different localization that to the tumor itself.

Chromosomal copy number changes supporting the classification of lentiginous junctional melanoma of the elderly as a subtype of melanoma.

Recently the term lentiginous melanoma of the elderly has been suggested for a pattern of melanocytic neoplasia characterized by frequent occurrence in elderly patients, broad lentiginous growth pattern, with poorly cohesive nesting, suprabasilar extension of melanocytes and moderate cytological atypia. However, there are limited reported cases with follow-up information to confirm the malignant nature of these neoplasms. Using fluorescence in situ hybridization (FISH) targeting chromosomal loci that are frequently found to have copy number changes in melanoma, we evaluated cases of lentiginous junctional melanoma of the elderly in order to compare with the frequencies and patterns of chromosomal aberrations identified in other subtypes of melanoma. Previous studies have shown that by using a FISH assay targeting 6p25, 6q23, 11q13 and CEP6 with previously validated criteria, one could discriminate benign nevi from melanoma with high sensitivity and specificity. In this study, 16 of 19 cases (84%) showed sufficient copy number changes in one of the targeted chromosomal loci to meet FISH criteria for melanoma. A total of 17 control cases of lentiginous junctional nevi tested negative for all criteria. These findings support the classification of this pattern of melanocytic neoplasia as a subtype of melanoma.

Lentigo maligna and superficial spreading melanoma are different in their in situ phase: an immunohistochemical study.

Clinical and pathologic observations have prompted the categorization of malignant melanoma into 4 subtypes. Although some authorities challenge the value of this classification, nevertheless it is generally accepted that lentigo maligna (LM), or melanoma on sun-damaged skin, has a different biological behavior than so-called superficial spreading melanoma (SSM), at least in the early stage of its evolution. To characterize some aspects of this different behavior, the in situ phase of SSM and LM was studied using immunohistochemical methods. Seventeen cases of SSM in situ and 13 cases of LM were chosen for the study. All cases qualified with strict histologic criteria. Sections from these lesions were stained with antibodies against HMB-45 antigen, basic fibroblast growth factor (bFGF), proliferating cell nuclear antigen (PCNA), and factor VIII. Semiquantitative analysis was performed. Cases classified as either LM or SSM corresponded well to the epidemiologic and clinical characteristics as described in the literature; that is, LM appeared in older patients and occurred mostly on the face, whereas SSM occurred mostly on the trunk and lower limbs. Although no difference in HMB-45 stain was observed, melanoctyes of SSM showed greater proliferative activity, as reflected by PCNA stain (P < 0.02) and higher levels of bFGF (P < 0.001), than melanocytes of LM. More blood vessels were counted under SSM than under LM (P < 0.05). These results are in accordance with the biological behavior of SSM and LM, that is, the longer in situ phase of the latter. bFGF is both a growth factor for melanocytes and an angiogentic factor. The differences in PCNA, a proliferation marker, and blood vessel count may be related to the bFGF effect. Thus this study reveals some of the biological differences between LM and SSM. Location and sun exposure habits may contribute to these differences, which already exist in the in situ phase.

[Lentigo maligna and lentigo maligna melanoma of the cheeks. Analysis of different growth patterns via photographic records]. / Altersmelanome (LM, LMM) an beiden Wangen Analyse der unterschiedlichen Wachstumsdynamik anhand photokatamnestischer Befunde. Analyse der unterschiedlichen Wachstumsdynamik anhand photokatamnestischer Befunde.

The dynamics of tumor growth of malignant melanoma may be reconstructed by evaluation of suitable private photographs of the patient. Photohistorical investigations can greatly aid in following the course of development of malignant melanomas and show impressively the slow and protracted growth of initial melanomas. We report on a 90-year-old patient with an in situ melanoma (lentigo maligna) and an invasive lentigo maligna melanoma in the facial region. We were able to obtain complete series of photographs from this patient, which show the different development of the two melanomas over a period of more than 30 years. The first tumor to appear developed very slowly while the later one showed invasive growth after a short time period. Development of multiple primary melanomas is a well recognized phenomenon. The presence of multiple primary melanomas does not appear to be a negative prognostic factor. However, patients with primary melanoma should be made aware of increased risk of development another primary and physicians should do careful total body skin examinations for new primary melanomas as well as for recurrences of the original melanoma.

Malignant melanoma, dysplastic melanocytic nevi, and Spitz tumors. Histologic classification and characteristics.

The classification and pertinent histopathologic features of cutaneous melanoma, dysplastic melanocytic nevi, and Spitz tumors are presented. A discussion on melanoma emphasizes an objective approach to classification based on histomorphologic features including location in the skin, disposition and frequency of melanocytes, other specific morphologic features, and cell type. Other topics addressed include common and unusual variants of melanoma, the use of immunohistochemistry, and the histopathologic reporting of melanoma.

Lentigo maligna and malignant melanoma in situ, lentigo maligna type.

Some authors have considered lentigo maligna to be an atypical melanocytic proliferation, whereas others have considered it to be melanoma in situ. We reviewed 50 cases of lentigo maligna. We have identified two subsets of lesions. The first has atypical melanocytic hyperplasia, which we postulate to be correctly designated lentigo maligna. The second subset has the following features in addition to the melanocytic hyperplasia: individual and nests of cells at varying layers of the epidermis, confluence of the melanocytes replacing the basilar region, uniformity of the cytological atypia, and nesting of uniformly atypical melanocytes. These lesions we designate as malignant melanoma in situ, lentigo maligna type. We are proposing that the lesions that have been termed lentigo maligna represent a spectrum of atypia and that the application of some of the traditional features for the diagnosis melanoma may permit the segregation of more and less aggressive lesions.