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Query: UMLS:C0025202 (melanoma)
 69,561 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A causative role of UV light in the development of melanocytic neoplasms has often been suggested. In order to investigate the short-term effects of UV light on melanocytic nevi, the morphological and immunohistochemical changes in nevi after a single UV irradiation are studied in 12 nevi from 10 patients and compared with the nonirradiated part of the same nevus. After irradiation more melanocytes above the dermal-epidermal junction are observed in seven nevi, simulating a melanoma in situ in three nevi. Moreover, a marked increase in the expression of HMB-45 is found after irradiation in all investigated nevi, indicating an activation of the melanocytes and active melanosome formation. The metabolic activity correlates with the ultrastructural findings, which show a large cytoplasm, hypertrophic Golgi apparatus, abundant mitochondria, and an increased number of melanosomes of different stages. One week after irradiation, no increase in the proliferative activity of the melanocytes is found. The morphological and immunohistochemical changes after one low dose of UV irradiation should be considered in the differential diagnosis of pigmented skin lesions. The UV-irradiated nevus should be added to the list of so-called simulators of malignant melanoma.
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PMID:UV-irradiated melanocytic nevi simulating melanoma in situ. 769 3

Ultraviolet (UV) light represents one of the factors that might play a role in the initiation and promotion of malignant transformation of human melanocytes. To determine the short-term effects of UV irradiation on melanocytic nevi in vivo, we investigated one half of symmetric melanocytic nevi after a single UV exposure with double the patient's minimal erythema dose. This half was compared with the nonirradiated, shielded half of the same nevus. The different parts were examined histologically for differences and immunohistochemically for the presence of HMB-45 antigen and proliferating cell nuclear antigen. The features were assessed quantitatively by image analysis. One week after the single UV irradiation, we observed a significant increase of suprabasally located melanocytes and a markedly enhanced expression of HMB-45, whereas proliferative activity of the cells was unchanged. In nevi that were excised 2 or 3 weeks after irradiation, no significant differences were observed between the irradiated and the nonirradiated part. The results indicate that a single UV irradiation may induce transient melanocytic activation with morphologic and histologic changes. Although these data do not formally assess resemblance to melanoma, these changes may be similar to those of melanoma in situ.
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PMID:Ultraviolet irradiation induces acute changes in melanocytic nevi. 770 61

Epidermotropic metastatic malignant melanoma (EMMM) is a well-recognized entity that can simulate primary malignant melanoma, and in the past reports of numerous (> or = 100) such lesions were misconstrued as multiple primary lesions. We present the cases of two patients who had not only numerous epidermotropic metastases that simulated primary melanomas but also 10 lesions that mimicked melanoma in situ. After removal of a primary malignant melanoma, the two patients developed 35 and 22 epidermotropic metastases over a 4-year period before dying with brain and pulmonary metastases, respectively. In these patients, 29 and 22 of the skin lesions were excised, respectively. All had epidermotropic metastases, of which seven and three showed pagetoid melanocytes in a pagetoid pattern exclusively within the epidermis and epithelial structures of adnexa, an "epidermal only" (in situ) pattern. Other lesions showed a continuum of dermal involvement, from the more conventional description of EMMM with the extent of dermal involvement > or = epidermal (n = 2) to epidermal involvement > dermal disease (n = 36). This histologic spectrum of dermal versus epidermal involvement in conjunction with the extremely small size (2.8 mm average histologic diameter), symmetry, large number, and time course of development argues strongly that these lesions represent metastases rather than multiple primary melanomas. The lesions illustrate the diagnostic dilemma posed by EMMM that simulates primary melanoma and further exhibits an "epidermal only" (melanoma in situ) pattern.
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PMID:Epidermotropic metastatic malignant melanoma simulating melanoma in situ. A report of 10 examples from two patients. 855 19

Solar lentigines ("liver spots") commonly occur on sun-damaged skin in the elderly population. Although they are benign, it is difficult in practice to distinguish solar letigines and junctional nevi from melanoma in situ. We report a patient who developed melanoma on the same site as a previously diagnosed solar lentigo. We also review the histopathological criteria for differentiating these benign lesions from potentially malignant ones.
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PMID:Melanoma in situ on facial skin damaged by sunlight. 803 Jul 70

We have applied DNA flow cytometric analysis to paraffin-embedded tissue sections of primary malignant melanomas. Conventionally, flow cytometric analysis of paraffin-embedded tissue sections has been done by the method of Hedley et al. We added ultrasound treatment to the method of Hedley et al. and a lower value of coefficient of variation was shown. Furthermore, a new technique, fluorescence in situ hybridization with a chromosome-specific repetitive DNA probe, was used for the analysis of chromosomal numerical aberrations in the same paraffin-embedded tissue sections. The DNA flow cytometric analysis showed that in 8 cases six primary malignant melanomas were of the aneuploid pattern and two cases of lentigo maligna (melanoma in situ) were of the diploid pattern. By fluorescence in situ hybridization, the two cases with the diploid pattern had spots/nucleus of 1.28 and 1.12, and those with the aneuploid pattern had spots/nucleus from 2.01 to 2.27. Only one nodular melanoma in an aneuploid case showed spots/nucleus of 1.71. These data indicate that fluorescence in situ hybridization with chromosome-specific repetitive DNA probes can serve as a cytogenetic tool for the analysis of interphase nuclei of solid human tumors and may be useful for the study of tumor cell heterogeneity.
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PMID:Applications of DNA flow cytometry and fluorescence in situ hybridization using a chromosome-specific DNA probe on paraffin-embedded tissue sections of primary malignant melanomas. 815 16

The discrimination between subungual pigmented nevus and subungual melanoma in situ is still a clinical problem. We measured DNA ploidy in six cases of subungual melanotic lesions which exhibited the features of subungual pigmented nevus or lentigo simplex histologically. Five cases presented a diploid pattern with or without a slight increase of hyperdiploid cells. One case presented a polyploid pattern; it also exhibited histologically abnormal melanocytes with large nuclei and pigment-filled elongated dendrites. The DNA ploidy pattern and histologic features suggest that the lesion of this latter case contains abnormal melanocytes which probably have the potential to undergo a malignant transformation into a subungual melanoma. DNA ploidy analysis, therefore, is likely to provide information for evaluating the biologic behavior of subungual melanotic lesions.
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PMID:Subungual pigmented nevus: evaluation of DNA ploidy in six cases. 824 7

The role of estrogen in the initiation and progression of melanoma remains unclear. Some findings that suggest a hormonal role in melanoma initiation or progression include the following: (1) melanomas arising during pregnancy are thicker than those in nonpregnant women, (2) pregnant women with stage II (regional nodal metastases) melanoma have a worse prognosis than nonpregnant women of similar stage, and (3) melanoma is rare prior to puberty. Although biochemical assays have shown that estrogen-binding proteins are present in malignant melanoma, studies using a sensitive and more specific immunohistochemical technique have not found estrogen receptors (ERs) in melanoma. In our laboratory an immunohistochemical technique using monoclonal antibody H222 can detect ER in tumors with receptor levels lower than 9 fmol/mg protein and detects ER in a variety of tissues and species. In addition, monoclonal antibody KD68 is used to detect progesterone receptors immunohistochemically. We studied 14 cases of pregnancy-associated melanoma. None of our cases, ranging from melanoma in situ to metastatic melanoma, showed positive nuclear staining for ER, nor did any of these cases show positive immunohistochemical staining for progesterone receptor. Despite the wide tissue and species distribution of ER detected by the monoclonal antibody H222, this immunohistochemical technique does not appear to be useful in the study of possible hormonal effects on the progression of malignant melanoma. The estrogen-binding proteins in melanoma detected by biochemical techniques in previous studies probably are distinct from the well-defined human ER.
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PMID:Estrogen and progesterone receptor analysis in pregnancy-associated melanoma: absence of immunohistochemically detectable hormone receptors. 831 59

A 60-year-old woman with superficial spreading melanoma in situ, measuring 2.5 mm in diameter, was examined. She had noticed a very small pigmented lesion 1.2 mm in diameter on her left lower leg in April of 1989. By April of 1990, it had grown to 2.5 mm in diameter. Its edge was irregular, and its color was variegated black to brown. Skin surface markings had disappeared in the center portion. Histopathologically, the lesion was asymmetrical. Atypical large cells nested in the lower epidermis and were scattered singly in the mid and upper epidermis, as seen in Paget's disease. At the periphery of the lesion, single large tumor cells were scattered in the mid epidermis. The tumor cells reacted to monoclonal anti-melanoma antibody HMB-45.
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PMID:A case of superficial spreading melanoma in situ 2.5 mm in diameter. 840 26

The National Institutes of Health Consensus Development Conference on Diagnosis and Treatment of Early Melanoma brought together experts in dermatology, pathology, epidemiology, public education, surveillance techniques, and potential new technologies, as well as other health care professionals and the public, to address (a) the clinical and histological characteristics of early melanoma; (b) the appropriate diagnosis, management, and follow-up of patients with early melanoma; (c) the role of dysplastic nevi and their significance; and (d) the role of education and screening in preventing melanoma morbidity and mortality. Following 2 days of presentations by experts and discussion by the audience, a consensus panel weighted the evidence and prepared a consensus statement. The panel agreed (a) that melanoma in situ is a distinct entity that can be treated effectively by surgery with 0.5-cm margins and that thin, invasive melanoma < 1 mm thick has the potential for long-term survival in < 90% of patients after surgical excision with a 1-cm margin; (b) that elective lymph node dissections and extensive staging evaluations should not be recommended in early melanoma; (c) that patients with early melanoma are at low risk for relapse but may be at high risk for development of subsequent melanomas and therefore should be followed closely; (d) that some family members of patients with melanoma are at increased risk for melanoma and therefore should be enrolled in surveillance programs; and (e) that education and screening programs have the potential to decrease morbidity and mortality from melanoma. The full text of the consensus panel's statement follows.
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PMID:National Institutes of Health Consensus Development Conference Statement on Diagnosis and Treatment of Early Melanoma, January 27-29, 1992. 843 32

Cutaneous malignant melanoma and its precursors were the general subjects of the National Institutes of Health Consensus Conference held in January 1992. Particular emphasis was placed on the diagnosis of early melanoma, especially melanoma in situ, and the controversies surrounding dysplastic nevi. Recent studies of unusual nevi often confused with melanoma, eg, deep-penetrating (plexiform) nevus, combined nevus, desmoplastic melanocytic nevus, and Spitz nevus in childhood, provided detailed histologic criteria for their discrimination from melanoma. Rare or unusual forms of melanoma, including desmoplastic melanoma, neurotropic melanoma, a newly described variant angiotrophic melanoma, subungual melanoma, and balloon cell melanoma have been the subject of comprehensive histologic studies. Other histopathologic investigations have described the prevalence of histologic regression and intraepidermal pagetoid spread in melanomas and the histologic features of reexcision specimens of melanoma. New evidence suggests that the predominant cell type infiltrating melanoma is the monocyte-macrophage, and the expression of monocyte chemotactic protein-1 by melanoma may explain the recruitment of this cell type. Immunopathologic studies of melanocytic lesions were performed with various melanocyte-associated antigens (eg, HMB-45), proliferation antigens (eg, Ki-67), and progression markers (eg, epidermal growth factor receptor and HLA-DR). HMB-45 binding has been localized ultrastructurally to early melanosome formation. Various prognostic factors, including gender, high-risk anatomic sites (particularly the scalp), race (black vs white patients), microscopic satellites, tumor volume, indices of proliferation and tumor cell motility, volume-weighted mean nuclear volume, DNA ploidy, and nucleolar organizer regions have been the subject of recent investigations. Analysis of many patients with long-term follow-up has facilitated better prognostic modeling of melanoma.
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PMID:Pathology and prognostic factors. 845 20


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