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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A series of 233 consecutive primary cutaneous melanomas was histologically and clinically studied. Histologically, 53 melanomas (22.7%) were associated with naevus cells. Such a high degree of association suggests that melanocytic naevus may be a precursor of a large number of melanomas. Analysing the cases according to Clark's levels and Breslow's index, a decrease in the naevus-melanoma association was seen with tumour progression, suggesting that advanced tumours may overgrow pre-existing nevus cells, appearing as de novo melanomas. The comparison between histological and clinical data suggest some interpretations of the natural history of melanoma.
Melanoma Res
PMID:Spatial association of melanocytic naevus and melanoma. 182 33

Congenital nevi (CN) can be recognized at birth or shortly thereafter. In adults, only those nevi over 5 cm in diameter can be assumed to be congenital in the absence of documentation in infancy. CN cannot be identified with certainty by histological examination, nor can melanomas be presumed to originate from CN on the basis of histologic findings. Up to 5% of patients with large CN (as defined by the National Institutes of Health (NIH) consensus information) will develop melanoma, and 80% of these will appear before the age of seven years. Increased risk of melanoma from smaller CN has not been substantiated. Although total excision of large CN immediately following birth would reduce the approximate 5% risk for melanoma from these lesions, because of the complexity of the procedure, large lesion removal is seldom completed prior to the ages of 7 to 10 years, and nevus cells frequently remain at the base of the excision with resultant negligible risk reduction. Melanoma risk from large CN is predominantly risk of melanoma in childhood. CN do not contribute significantly to risk for adult melanoma. Sunburn constitutes the most important reducible risk factor for adult melanoma. Ultimately, the greatest hazard of large CN is not melanoma risk but cosmetic deformity.
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PMID:The management of congenital pigmented nevi. 207 85

Melanoma growth stimulatory activity (MGSA) was originally described as an endogenous growth factor for human melanoma cells. To test the hypothesis that an MGSA autocrine loop is responsible for the partial freedom from growth control observed in nevocytes and melanoma cells, MGSA growth response and MGSA mRNA/protein levels were examined in these cells compared with normal melanocytes. As a single agent, or in combination with other factors, MGSA stimulated the growth of normal human epidermal melanocytes as well as other growth promoters for melanocytes. Nevocytes were not as responsive to exogenous MGSA as melanocytes. MGSA mRNA was minimal or not detected in cultured normal melanocytes, although the protein was present when the cells were cultured in the presence of serum/growth factors and absent when serum/growth factors were omitted. In contrast, MGSA mRNA was constitutively expressed in the absence of exogenous growth factors in cultures established from benign intradermal and dysplastic nevi and melanoma lesions in different stages of tumor progression. Nevus cultures contained immunoreactive MGSA protein in the presence of serum but were negative or only faintly positive in the absence of serum. Melanoma cell lines were positive for MGSA protein in both the presence and the absence of serum. Thus, continued expression of both MGSA mRNA and MGSA protein in the absence of exogenous hormones or serum factors may correlate with partial freedom from growth control exhibited by malignant melanocytes.
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PMID:Characterization of the role of melanoma growth stimulatory activity (MGSA) in the growth of normal melanocytes, nevocytes, and malignant melanocytes. 209 66

Melanoma incidence is rapidly increasing in several countries. This neoplasm has been consistently studied in patients with dysplastic (pleomorphic) nevus, mainly in Anglo-Saxon populations. There is no evidence that among Italians the sequence pleomorphic nervus----cutaneous malignant melanoma shares the identical pathophysiologic mechanisms with the above mentioned form. Pleomorphic nevi are generally thought to be precursors of malignant melanoma of the skin, due to their chromosomal instability. Also common acquired nevi are lesions which can exhibit, although exceptionally, chromosomal abnormalities. Consequently, the sequence pleomorphic nevus----cutaneous malignant melanoma could also include the common nevus. The clinical implications of this stand-point, however, are to be more extensively investigated.
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PMID:[Etiopathogenesis of malignant melanoma of the skin. I. Clinico-biological and nosologic considerations]. 219 27

Normal human cells, cells from nonmalignant proliferative lesions, and primary and metastatic tumor cells can be maintained in vitro and analyzed for requirements for growth in chemically defined media. The human melanocytic cell system with normal melanocytes, precursor nevus cells, and primary and metastatic melanoma cells has been extensively studied for the phenotypic properties of the cells, including their requirements for exogenous growth factors and other mitogens. In high calcium-containing W489 medium, normal melanocytes require four supplements: IGF-I (or insulin); bFGF, TPA, and alpha-MSH. Nevus cells are largely independent of bFGF. Depletion of TPA from medium is not as detrimental to nevus cells as it is to melanocytes, but the phorbol ester is still essential for maintenance of the typical nevic phenotype. Primary melanoma cells require at least one growth factor, IGF-I (or insulin), for continuous proliferation. On the other hand, metastatic cells of melanoma as well as of carcinomas of colon and rectum, bladder, ovary, and cervix are able to proliferate after a short adaptation period in medium depleted of any growth factors and other proteins. Doubling times of metastatic tumor cells in protein-free medium are only 30-60% longer than in FCS-containing medium. The growth autonomy of human tumor cells is apparently due to the endogenous production of growth factors. Likely candidates for autocrine growth stimulation of human tumor cells are TGF-alpha, TGF-beta, and PDGF. Melanoma and colorectal carcinoma cells express functional EGF/TGF-alpha receptors, and produce TGF-alpha, indicating that this growth factor is produced for autocrine stimulation. In addition to the use of anti-growth factor antibodies, other strategies for the inhibition of autocrine growth stimulation include mAbs to growth factor receptors, soluble receptors, receptor-mimicking antiidiotype antibodies, and active immunization against growth factors. Whether any of these therapeutic approaches is clinically feasible will need to be determined in extensive preclinical investigations.
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PMID:Growth-regulatory factors for normal, premalignant, and malignant human cells in vitro. 240 78

A study of 121 melanoma patients and 139 control subjects was conducted among whites to examine and compare the distribution of non-dysplastic and dysplastic naevi and other pigmented lesions in each group. Melanoma patients had a mean of 97 melanocytic naevi which were greater than 2 mm in diameter and controls had a mean of 36 such naevi, while the medians were 58 and 22 respectively (p less than 0.0001). 55% of melanoma patients and 17% of controls had at least one clinically determined dysplastic naevus, and 26% of melanoma patients and 6% of controls had at least 5 dysplastic naevi. Men were found to have more naevi on the trunk than women in both melanoma cases (p = 0.01), and controls (p = 0.005). Dysplastic naevi were most often found on the trunk and were present at this location in 51% of cases and 17% of controls. Melanoma patients and control subjects with dysplastic naevi, when compared to those without these lesions, had larger number of non-dysplastic naevi. Lentigines were more common among melanoma patients that among control subjects (p = 0.02). There were no differences in the number of non-dysplastic naevi among cases with light and dark hair and eyes, or among controls with these characteristics. There also was little variation in the number of naevi according to number of blistering sunburns.
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PMID:The distribution of melanocytic naevi in melanoma patients and control subjects. 248 46

Melanoma most often develops in the skin; usually at the site of a preexisting nevus. It is quite rare in the oral cavity and the maxilla is the most common location there. It appears that males between 60 and 70 years old are affected more often than females. The etiology is unknown. However the melachromatic nevus and the color of the skin are considered predisposing factors. Based on clinical and histologic criteria it is classified in three categories. Unfortunately the frequency of the occurrence of each category into the mouth separately, is inversely proportional to the prognosis. The 5 year survival rate of intraoral melanoma does not exceed 5-9%. The treatment of melanoma is surgical and comprises radical excision of the lesion and radical neck dissection. Radiotherapy and chemotherapy do not seem to contribute to the treatment. We present our experience of two patients with melanoma of the maxilla. In one case submandibular lymphadenopathy had already been established and a radical neck dissection was performed. In the other case subtotal maxillectomy was performed with intraoral approach.
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PMID:[Primary melanoma of the oral cavity]. 264 Jun 48

The incidence of cutaneous malignant melanoma (CMM) is increasing at an alarming rate. Risk factors that may contribute to the increase include ultraviolet (UV) radiation, lack of skin pigmentation, and genetic, hormonal, and immunologic factors. Although the exact nature of the relationship between melanoma and UV radiation is unclear, evidence suggests a correlation between sun exposure and CMM incidence. Caucasians with fair skin who sunburn and freckle easily and individuals with numerous nevi or moles and/or atypical nevi or moles are also at increased risk of CMM. Melanoma almost always is curable by surgery if it is detected early. Nursing can make a major contribution to reducing the morbidity and mortality of CMM both through educating the public in prevention and early detection measures and by screening individuals for suspicious lesions.
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PMID:Cutaneous malignant melanoma: nursing's role in prevention and early detection. 266 Jan 18

Malignant melanomas of the skin are becoming more common. Earlier diagnosis has led to better individual prognoses, but this has not prevented the death rate in the population from rising. This paper brings up-to-date studies on the etiology of malignant melanoma, and supplements various fuller but earlier reviews. Melanoma risk is increased in lightly pigmented people who burn in the sun and do not tan well. People with an increased number of nevi are also at increased risk. Latitude of residence is important, risk in white populations increasing with distance from the poles. Phenotypic factors can over-ride location, so that Mediterranean people have lower rates than Scandinavians. Melanomas are concentrated on sites exposed by clothing, but this concentration is not as strong as for the other skin cancers. Migrants to sunny climates are at less risk than similar people born locally, provided that they migrated as adults. Outdoor work carries only a small excess risk of malignant melanoma, in contrast to the other skin tumors. Melanomas are commoner, and kill more often, among people of high socioeconomic status than low. The two most detailed contemporary reconciliations of these pieces of evidence are based on the ideas that intense brief exposure is the critical factor, or that exposure in childhood is of major importance. With the expected changes in the global concentration of ozone in the stratosphere, it is necessary to estimate the relationship between the intensity of sunlight and melanoma risk.
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PMID:The relationship between malignant melanoma of skin and exposure to sunlight. 268 4

Nevus cell components have been observed in up to 40% of melanomas, but little is known of the pathobiology of these components in relation to their malignant potential. We studied 44 nevi of the typical, dysplastic, congenital, and Spitz types with a battery of monoclonal and polyclonal antibodies that react on formalin-fixed, paraffin-embedded tissues (HMB.45, S-100 protein, RAP-5, epithelial membrane antigen [EMA], and neuron-specific enolase [NSE]) by avidin-biotin immunohistochemical methods. EMA and RAP-5 (which detects the ras oncogene-associated P21 protein) were negative in all cases. Melanoma-specific HMB.45 was strongly reactive with the epidermal component and had a weak to negative reaction with the dermal component in the typical nevi. However, the reaction seen with HMB.45 in the junctional component of dysplastic nevi, congenital nevi, and some Spitz nevi was heterogeneous. One Spitz nevi showed HMB.45 staining in a pattern near to that of melanoma. In contrast to HMB.45, S-100 protein labeled nevomelanocytes, regardless of whether they were within the epidermis or dermis, although, in half of the dysplastic nevi, the reaction was heterogeneous, with some atypical cells failing to stain. But, with cytologically atypical junctional component (dysplastic-appearing), congenital nevi also stained heterogeneously for S-100 protein compared with the dermal component. NSE stained the central component of some Spitz nevi more intensely than the lateral component. Junctional nevomelanocytic subsets of some congenital nevi revealed HMB.45 and S-100 reactivity similar to dysplastic nevi.
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PMID:Typical, dysplastic, congenital, and Spitz nevi: a comparative immunohistochemical study. 229 3


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