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

The present study discusses, in the light of the comparatively restricted data in the speciality literature, two cases of anorectal melanoma emphasizing the histologic diagnostic difficulties linked to appraisal of the limits of the benign naevus formations, predominance of the achromatous zones, alternation of the benign and sarcomatous fascicular proliferations and those of the anaplastic carcinoma type. Stress is laid on the importance for the diagnosis of the histologic examination and of serial sections, in all pedunculate formations in the anorectal region as well as of the tests applied for detecting melanin.
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PMID:Anorectal melanoma. Problems of histopathologic diagnosis. 13 75

An unusual variant of juvenile melanoma, namely a sclerosing juvenile melanoma occurring on the buttock, has been studied by light and electron microscopy. The diagnosis of a pigment tumour was confirmed by the presence of structures common to these lesions, i.e. melanosomes, intracytoplasmic fibrils and microvilli on the cell surface. The tumour consisted of two cell configurations, namely a multinucleated giant cell and a second cell made up of two separate cells lying in close apposition, the cytoplasm of one cell being dark and the other light. This tumour can be differentiated from a benign naevus by the bizarre histological appearance on light microscopy. On electron microscopy the distinction is made by the presence of the very large multinucleated giant cells, the apposition of the light and dark cells, the scanty melanosomes and the presence of intracytoplasmic lumina. The value of electron microscopy in the determination of the nature of unusual skin tumours is discussed.
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PMID:An ultrastructural study of a juvenile melanoma. 42 24

Familial occurrences of malignant melanoma may be related to an inherited syndrome of precursor cutaneous lesions with distinct clinical and histologic features. Recognition of the syndrome in the relatives of melanoma patients identifies a subset of family members at high risk for melanoma, facilitating their early diagnosis and treatment. Further studies of these families may provide insight into the biology of malignant melanoma and the pathophysiology of malignant transformation in benign nevi.
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PMID:Precursor lesions in familial melanoma. 63 99

Previous studies have demonstrated a specific cytoplasmic fluorescence in human melanocytes, as well as in pigmented nevi and in malignant melanomas, when the formaldehyde histofluorescence method for visualization of certain catechol and indole derivatives was used. In malignant melanoma two fluorogenic substances, dopa and cysteinyldopa, were found previously. In human melanocytes and benign nevi cells the fluorogenic catechols have so far not been characterized, since chemical analyses are difficult to perform on skin, due to the small amounts of catechols present. However, using split thickness skin quantitative determinations are possible by sensitive fluorometric methods. The chemical analyses of cysteinyldopa showed that in human adult skin most or all was located in the superficial layers. The only specific fluorescence in the thin skin was found in dendritic melanocytes. The findings leave little doubt that cysteinyldopa is stored in melanocytes although the possibility of a concomitant occurrence of other thioethers is not excluded. Nevi and giant nevi were also similarly studied and we found considerable amounts of cysteinyldopa in the nevi. It seems as if the cysteinyldopa is stored in the fluorescent nevi cells. There was no consistent difference in the content of the catechol derivatives between intradermal and compound nevi.
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PMID:On the occurrence of cysteinyldopa and dopa in melanocytes and benign nevi cells. 105 47

Direct leukocyte migration inhibition (LMI) assays were performed to investigate whether cell-mediated immune reactions could be detected in response to tumor-associated antigens of human melanoma. The antigens were 3 M KCl-soluble extracts of different fresh melanomas, other cancers, and benign nevus tissue. A total of 48 of the 79 (61%) blood samples from melanoma patients (64 patients) reacted with extracts of melanoma tissue. Since the subjects were usually tested with two or three extracts, 57/134 (42%) tests with melanoma patients' leukocytes were inhibited by KCl extracts of melanoma tissue, whereas only 3/50 (6%) tests with leukocytes of normal donors and 4/27 (15%) with patients having other cancers gave positive results. No positive reactions were obtained when 13 melanoma patients were tested with a 3 M KCl extract of benign nevus tissue. Likewise, only 2/26 (8%) positive tests were obtained from melanoma patients tested with extracts of other cancers. Individuals in all stages of disease had similar incidences of positive reactions to the soluble melanoma extracts, except for patients with stage-1 disease who exhibited a somewhat higher incidence of reactivity. The highest incidence of reactivity was observed in patients before surgical resection of the tumor, and somewhat decreased reactivity was seen 0-14 days post surgery. The results indicate that the direct LMI assay may be used to measure cell immune reactivity against melanoma-associated antigens. Since many of the positive results were obtained with allogeneic extracts, the results also indicate that different melanomas possess common antigens.
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PMID:Inhibition of leukocyte migration by tumor-associated antigens in soluble extracts of human malignant melanoma. 105 54

Ninety-five cases of malignant choroidal melanoma collected during a 15-year period have been studied with special emphasis on histological type, coexistence of benign nevus, and prognosis. Elements of benign nevus were found in 78% of the cases. The data tend to support the hyposis that most cases of malignant choroidal melanoma have their origin in a preexisting benign nevus, and that the tumours undergo a gradual change from a differentiated to a less differentiated type.
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PMID:Malignant melanoma of the choroid as related to coexistent benign nevus. 117 95

In 21 patients with a variety of skin tumors (squamous cell carcinomas, malignant melanomas, basal cell epitheliomas and mycosis fungoides) or pre-cancerous lesions (Bowen's disease, actinic keratosis, junctional nevus cell nevus) the radioactive phosphorus uptake test demonstrates a significantly increased concentration of P32 in those tumors. There were no false negative tests. The possibility of differentiation of malignant melanoma from benign nevus cell nevus and the early recognition of cutaneous metastases is described. Furthermore recurrence of previously irradiated or excised basal cell epitheliomas can be detected without a biopsy. No hematological side-effects were observed.
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PMID:[The radiophosphorus (32P)-test in precanceroses and malignant tumors of the skin]. 127 Feb 58

Expression of the endothelial adhesion molecule VCAM-1 was studied in human malignant melanoma lines by flow cytometry. Clones 2/4 and 2/14 (derived from the same lesion) had appreciable levels of VCAM-1 expression, whereas clone 2/21 and the lines A2058, Mel24, and A375 were negative. Clone 2/14 was selected for further analysis. Exposure to tumor necrosis factor (TNF) markedly augmented VCAM-1 on melanoma cells. Surface VCAM-1 was associated with expression of specific transcripts that were augmented by TNF. Analysis by reverse transcriptase and polymerase chain reaction using appropriate primers revealed that TNF-stimulated melanoma cells expressed both 7 and 6 immunoglobulin domain transcripts with predominance of the longer species. Tumor necrosis factor--stimulated melanoma cells bound more VLA-4-expressing cells (melanoma and monocytes) than resting tumor cells and anti-VCAM-1 monoclonal antibodies significantly inhibited binding, thus suggesting that surface VCAM-1 on melanoma is functional. Analysis of melanoma tissue sections demonstrated that VCAM-1 is not a marker of transformation of melanocytes because it can be detected in benign nevi. Although, unlike ICAM-1, VCAM-1 is not correlated with tumor progression, its expression in a fraction of primary melanomas indicates that it may play a role in regulating host immune response and homotypic interactions in some malignant melanomas.
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PMID:Regulated expression of vascular cell adhesion molecule-1 in human malignant melanoma. 128 17

Malignant melanoma can produce diagnostic problems for the histopathologist because of its protean histologic patterns. The recently recognized signet cell pattern can be particularly confusing and must be distinguished from adenocarcinoma, tumors of vascular endothelium or adipose tissue, lymphoma, and epithelioid smooth muscle lesions. We report four new cases of signet cell melanoma and illustrate this pattern in primary as well as metastatic sites. In addition, we document the signet cell pattern in benign nevi for the first time, expanding the concept of this pattern to melanocytic cells in general. The differential diagnosis of signet cell melanoma and its mimics is discussed and the utility of immunohistochemical stains in this diagnosis is stressed.
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PMID:Signet cell melanocytic lesions. 134 15

Data obtained in experimental murine tumors and in clinical specimens of human breast cancer have suggested that the nm23 gene may function as a metastasis suppressor gene. In this report we examined the nm23 mRNA level in tumor tissue obtained from distant metastases in 33 patients with malignant melanoma. The gene was differentially expressed in the tumors with a 20-fold range in hybridization intensities. The levels of nm23 mRNA in benign nevi obtained from 12 of the 33 patients were relatively low, with a mean value of 17% of that in the melanomas. In attempts to relate the level of nm23 expression in the tumor metastases to progression of the disease, the time from biopsy of the primary tumor to the appearance of metastases was used as a clinical end point. It was found that patients developing metastases during the first 2 years after diagnosis had significantly lower levels of tumor nm23 expression (56% of the mean value) compared to patients with less aggressive disease (164%) (P < 0.0004). In concordance with previous data the association found here between low levels of nm23 mRNA and the malignant potential of melanomas suggests that the nm23 gene may be implicated in the mechanism of disease progression in some types of human cancer.
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PMID:Levels of nm23 messenger RNA in metastatic malignant melanomas: inverse correlation to disease progression. 135 24


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