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

Cultured melanoma cells are known targets for the pigment-inducing actions of melanotropins such as alpha-melanocyte-stimulating hormone (alpha-MSH). The objectives of the present studies were to determine the binding properties and functional relevance of MSH binding sites in a mouse melanoma cell line and to determine whether MSH receptors are expressed in situ. The binding properties of MSH receptors in intact cells of a highly metastatic, highly MSH-responsive mouse melanoma cell subline (B16-F10C23) were determined using a radiolabeled, biologically active preparation of the superpotent alpha-MSH analogue, [Nle4,D-Phe7]-alpha-MSH (125I-NDP-MSH). A single high-affinity class of binding site was detected (Kd for NDP-MSH, 5.6 x 10(-11) M; Kd for alpha-MSH, 2.6 x 10(-9) M as determined by Scatchard analysis and heterologous inhibition assays, respectively). alpha-MSH showed nearly identical concentration-response relationships in the radioreceptor assay (inhibition of 125I-NDP-MSH binding) and a bioassay (stimulation of intracellular cyclic AMP accumulation). Furthermore, the respective potencies of three melanotropins, NDP-MSH, alpha-MSH, and adrenocorticotropic hormone, in binding and biological assays were highly correlated. These results indicate that the 125I-NDP-MSH binding site represents the functional MSH receptor. Tumors were induced by inoculation of C57BL/6 mice with B16-F10C23 cells, and the presence of 125I-NDP-MSH binding sites was determined by in situ radiolabeling of frozen tissue sections followed by autoradiography. Specific MSH binding sites were distributed throughout the tumor tissue, but not in associated fibrovascular elements or in neighboring nonmelanoma tissues. As in cultured B16-F10C23 cells, melanotropins inhibited 125I-NDP-MSH binding to tissue sections in a concentration-dependent manner. These results support the hypothesis that functional MSH receptors are expressed in melanoma in situ, suggesting that the activities of melanoma cells in vivo may be subject to modulation by endogenous melanotropins. The methods described will be applicable for studies of the expression and regulation of MSH receptors in human melanoma and other target tissues.
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PMID:Melanotropin receptors of murine melanoma characterized in cultured cells and demonstrated in experimental tumors in situ. 215 54

Fluorescence in malignant melanoma cells was investigated. The specimens from 18 cases of malignant melanoma and 26 cases of nevocellular nevus, which were fixed with formalin and embedded in paraffin wax, were studied by the fluorescence microscopic method. On the fluorescence microscope, the malignant melanoma cells emitted intense fluorescence from the cytoplasm. The nevus cells with large amounts of melanin granules showed moderate fluorescence. The tumor cells of melanoma in situ and nevus cells with few melanin granules emitted little fluorescence. Not only malignant melanoma cells but also nevus cells in the formalin fixed specimens had various degrees of fluorescence. Many cases of malignant melanoma emitted intense fluorescence, but this was rarely found in nevocellular nevus. This method is also useful in differentiating melanoma from nevocellular nevus.
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PMID:A comparative study of fluorescence in malignant melanoma and nevocellular nevus using a fluorescence microscope and formalin-fixed specimens. 227 43

Neither the involvement of hairfollicles nor of the ducts of the sweat glands by melanoma cells nor the thickness of the epidermis are helpful in differential diagnosis of lentigo maligna melanoma and superficial spreading melanoma in situ. The epidermis was thinner in LMM, however, LLM is mostly localized in the face where the epidermis is thinner than in other areas of the integument.
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PMID:[Is involvement of skin appendages or thickness of the epidermis an aid in differential diagnosis between lentigo maligna melanoma and superficially spreading melanoma in situ?]. 229 Dec 95

Lentigo maligna is a precancerosis or a melanoma in situ, whose level of malignancy has not yet been definitively clarified. Recurrences are not rare after excision, even when an ample safe margin is observed. One reason for this is the existence of a subclinical ramification in the marginal area of the lentigo maligna. Such subclinical ramifications were investigated by means of excision with histological monitoring of the margins by the paraffin section technique. There was a clear relationship between the frequency of these ramifications and the clinical safe margin left in 64 excisions. With the aid of parametric evaluation methods the distribution of the subclinical portion referred to the distance from the clinical margin could be determined with a special formula. If an invasion, in the form of a lentigo maligna melanoma had already taken place, then the subclinical portion within the marginal area was significantly more extensive. For the treatment of lentigo maligna, and especially of lentigo maligna melanoma, we therefore recommend excision with histological monitoring of the margins. There were no local recurrences within an average follow-up period of about 2 1/2 years.
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PMID:[The subclinical portion in the periphery of lentigo maligna and lentigo maligna melanoma]. 234 98

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).
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PMID:[Histologic analysis of intraepidermal melanocytic proliferation in the peripheral area of superficially diffused melanoma]. 236 85

Primary malignant melanoma is an unusual lesion in the esophagus that is not infrequently seen in association with melanosis. A case of esophageal invasive malignant melanoma with melanosis is described in which the melanosis exhibited melanocytic atypia extending through to melanoma in situ. The authors know of no previously reported such finding.
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PMID:Primary malignant melanoma of the esophagus with diffuse melanocytic atypia and melanoma in situ. 258 47

Five cases of primary vaginal melanoma were treated at UCLA Medical Center between 1976 and 1986. Two additional cases of melanoma arising at the junction of the vulva and vagina are presented. One of seven (13%) patients is alive, with a median time to recurrence of 7 months, and median survival of 31 months. Four of five vaginal melanomas were located in the distal vagina, and all were advanced at diagnosis (greater than 3 mm depth). Mean size was 3 cm. Initial therapy was local excision in four patients and radical surgery in three. All patients had suboptimal surgical margins: two vaginal primaries had positive margins after local excision, both recurred vaginally within 5 months. Two patients had margins less than 1 mm, one died of distant metastases, the other is alive with disease 30 months after radical distal vaginectomy and hemivulvectomy with post-op pelvic radiotherapy. Three patients had melanoma in situ at the surgical margins, and each had pelvic recurrences between 6 and 26 months. Five of seven cases developed local recurrence as the initial site of treatment failure. All five vaginal cases ultimately developed distant disease, but only two patients had distant disease without local-regional recurrence. Chemotherapy and immunotherapy enabled disease stabilization in three patients. The vulvovaginal junction at the introitus is a high risk site for vaginal and vulvar melanoma. Intraoperative management requires assessment of lateral and deep spread of invasive and in situ melanoma.
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PMID:Vulvovaginal melanoma: report of seven cases and literature review. 264 20

Primary acquired melanosis (PAM), a disease that affects mostly middle-aged white patients, is predominantly a proliferative condition of the melanocytes that normally populate the conjunctival epithelium. Primary acquired melanosis without atypia (low risk for the development of melanoma) is typically created by increased numbers of melanocytes restricted to the basilar region of the epithelium without nuclear hyperchromasia or prominence of the nucleoli. Primary acquired melanosis with atypia, a formal precursor of melanoma, is characterized by the proliferation of small polyhedral cells, spindle cells, large dendritiform melanocytes, or epithelioid cells that may: remain restricted to the basilar region (basilar nests); form nests at all levels of the epithelium; spread individually to all levels of the epithelium (pagetoid extension); or proliferate in a sheet-like fashion approximating a melanoma in situ. Lesions composed of epithelioid cells or exhibiting intraepithelial pagetoid extension have, respectively, a 75 or 90% chance of eventuating in invasive melanoma. Primary acquired melanosis in an adult should not be confused with "a junctional nevus," which is almost always restricted to childhood. Invasive melanomas measuring less than 0.8 mm in thickness tend not to be associated with metastases; the tumor cells may be small polyhedral (in which case confusion with a compound nevus often arises), epithelioid, spindled, or ballooned. Nodules composed of spindle cells in part or in toto tend to have less metastatic potential at a given thickness measurement than comparable nodules composed of epithelioid or polyhedral cells. The clinical features, electron microscopic findings, and biologic principles underwriting clinical management are also presented.
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PMID:Clinicopathologic characteristics of premalignant and malignant melanocytic lesions of the conjunctiva. 264 38

This report describes the efficacy of skin examination for the early detection of second primary cutaneous melanomas among patients with nonfamilial melanoma. A series of 121 patients with newly diagnosed first primary cutaneous melanomas participated in a study of melanoma and dysplastic nevi. Of the 121 study participants, six patients were subsequently diagnosed with a second primary melanoma. For five of these patients, frequent skin examinations resulted in the detection of second primaries that were shallower in depth than was the first primary melanoma. In four cases, the second primaries were identified in low-risk growth phases (less than 0.76 mm); three of these low-risk tumors were melanoma in situ.
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PMID:Usefulness of frequent skin examination for the early detection of second primary cutaneous melanoma. 274 53

Subungual melanomas are one of the most common types of malignant melanoma among the Japanese population. Although most pigmented nail streaks are benign and remain unchanged in their color and shape for a long time, rarely are they precursor lesions of subungual melanomas i.e., a rapid growing pigmented nail streak resulting in diffuse melanosis of the nail is thought to be an early stage of subungual melanoma in situ. We found four patients with these changes: three of these patients were children. The lesions occurred on the right index finger, right thumb, left middle finger, and right great toe, respectively. A slightly haphazard combination of colors ranging from dark brown to black, the important characteristic of subungual melanoma in situ, was observed in two cases. In the remaining two cases, although the haphazard combination of colors was not distinctive, many fine, dark longitudinal lines were seen within diffuse, light-brownish pigmentation. Serial histologic examination of the excised tissue specimens showed great proliferation of vacuolated melanocytes with variable nuclear atypicality along the entire basal layer in all cases. These histologic changes were compatible with those of atypical melanocytic hyperplasia or intraepidermal melanoma (in situ melanoma), which is an early lesion of subungual melanoma. An adult case is thought to be a definite example of a subungual melanoma in situ. We also made the diagnosis of melanoma in situ in the remaining three cases of children with rapidly growing pigmented nail streaks because their histopathologic features were distinguishable from those of the adult case. However, there remains some hesitation about this because invasive subungual melanoma is rare in children.
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PMID:A rapidly growing pigmented nail streak resulting in diffuse melanosis of the nail. A possible sign of subungual melanoma in situ. 280 9


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