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

17 cases of giant congenital nevi were reported. The lesions were located on the scalp, on the back and on the shoulders. The histopathological study revealed two cellular types of giant nevus; nevus cell type and neuroid type. Two types of neuroid structures were observed in neuroid type: Verocay bodies and pseudo-Meissnerian corpuscles. The congenital nature of a benign nevus includes the presence of nevus cells, single or in nests within the follicular epithelium, eccrine ducts or glands. Essentially, all giant nevi show conspicuous nevic cell permeation not only of the reticular dermis but typically also of the subcutis and even the fascia.
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PMID:Giant congenital nevi. A clinical and histopathological study. 764 Mar 70

The histogenesis of malignant melanoma with particular reference to the role of melanocytic nevus is still controversial in oncological pathology. In order to differentiate between the proliferative activity of malignant melanomas and benign melanocytic tumors, immunohistochemical analysis was carried out. We used monoclonal antibody PC10 to identify the Proliferating Cell Nuclear Antigen (PCNA), a highly conserved 36 KD acidic nuclear protein which correlates with cell proliferation, and the AgNOR method to stain the Nucleolar Organizer Regions (NORs) whose number and configurations may reflect protein synthesis activity. 47 cases of primary melanoma, 63 metastatic melanoma lesions, and 23 cases of nevi are included in this study. Spitz nevi showed a higher index of cell proliferation compared with other common benign nevi but a much lower index compared with malignant melanoma cells. The metastatic lesions of malignant melanomas had a higher index of proliferation and activity of cells than the primary lesions. Skin-metastatic lesions had higher indexes of cell proliferation and NOR activity than lymph node-metastatic lesions. These results support the idea that metastatic melanoma cells are derived from a more advanced stage of tumor progression. These data suggest that the combination of PCNA and AgNOR is an useful marker for differentiating benign melanocytic tumors from malignant melanomas.
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PMID:PCNA expression and nucleolar organizer regions in malignant melanoma and nevus cell nevus. 773

We report seven cases of a distinctive type of malignant melanoma characterized by a deceptively benign histological appearance with an architecture resembling that of benign melanocytic nevi on scanning magnification. Two predominant architectural patterns were observed: a dome-shaped pattern (two specimens) and a verrucoid pattern (five specimens). The specimens with a dome-shaped pattern of growth were characterized by a smooth epidermal surface and a proliferation of epithelioid melanoma cells with an inconspicuous intraepidermal component resembling spindle and epithelioid cell nevi (Spitz nevi). Gradual diminution in the size of dermal nests toward the bases of the lesions simulating the maturation phenomenon of benign nevi was observed; however, the dermal organization in cords and strands of melanoma cells and the persistence of cellular atypia extending to the bases of the tumors allowed their recognition as malignant melanomas. On the other hand, the specimens with a verrucoid growth pattern consisted of broad, exophytic tumors with a verrucous epidermal surface resembling that of papillomatous dermal nevi but distinguished from them by the presence of a continuous proliferation of melanocytes along the dermal-epidermal junction and by confluent sheets of melanoma cells in the dermis without evidence of true maturation. Clinical follow-up showed local recurrence in three patients after intervals ranging from 5 months to 5 years and regional metastasis in one patient after 2 years. The lesions described here may constitute a serious pitfall for diagnosis because of their innocent silhouette on scanning magnification and their superficial resemblance to spindle and/or epithelioid cell nevi and benign verrucous melanocytic nevi. Proper attention to cytological detail and subtle architectural features will aid in recognizing this unusual variant of malignant melanoma.
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PMID:Nevoid melanoma: a clinicopathological study of seven cases of malignant melanoma mimicking spindle and epithelioid cell nevus and verrucous dermal nevus. 786 47

Stimulation of epidermal growth factor (EGF) receptor by ligands such as transforming growth factor (TGF) alpha may be associated with cell proliferation or transformation in both nevocytes and keratinocytes. Previously, EGF receptors have been identified within a variety of pigmented lesions, suggesting a possible responsiveness to ligands such as TGF alpha. In the present study, we characterize the intralesional expression and distribution of immunoreactive TGF alpha protein by avidin-biotin immunoperoxidase localization in benign nevi, congenital nevi, dysplastic nevi, and malignant melanomas. In situ hybridization techniques with TGF alpha riboprobes confirmed the constitutive production of TGF alpha in all types of pigmented lesions. The localization of TGF alpha expression to nevocytes when coupled with the previous reports of expression in basal keratinocytes suggests the possibility of either an autocrine mechanism of action for TGF alpha or a paracrine interplay of TGF alpha between keratinocytes and nevocytes within melanocytic lesions. An increase in immunoreactive TGF alpha in nevocytes was noted in both benign and dysplastic nevi from dysplastic nevus patients, as compared to benign nevi from normal patients. Congenital nevi and malignant melanomas showed an intermediate and variable level of TGF alpha immunoreactivity. When coupled with previous studies the data suggest linkage of the TGF alpha/EGF receptor pathway in the evolution of melanocytic lesions.
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PMID:Expression and distribution of transforming growth factor-alpha within melanocytic lesions. 796 61

Studies on melanoma cell lines indicate the expression of actin-binding protein (ABP), a peripheral cytoplasmic protein that crosslinks actin, is important for melanoma cell motility. We used an ABP-specific monoclonal antibody to characterize ABP expression in 18 benign nevi and 28 primary and metastatic malignant melanomas. Heterogeneous expression of ABP staining was observed in metastatic melanoma. No clear differences in ABP staining were identified among compound nevi, dysplastic nevi, and superficial spreading melanoma; however, the lentiginous intraepidermal component of the benign and malignant lesions and the pagetoid cells of superficial spreading malignant melanoma were negative for ABP. In contrast, the nested intraepidermal and dermal components of both benign nevi and primary malignant melanoma were positive. The differential expression of ABP of the lentiginous component as opposed to the intraepidermal nests and pagetoid cells of benign nevi or melanoma may represent a capacity of the nested melanocytes to migrate from the epidermis to the dermis during maturation or invasion. Taken together, the findings support that ABP may be important for cell-cell adhesion during tumorigenesis and may play a role in tumor cell ameboid motility during tissue invasion.
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PMID:Actin-binding protein expression in benign and malignant melanocytic proliferations. 786 58

Because the differential diagnosis of melanocytic tumors is sometimes difficult, we performed a morphometric analysis of 20 benign nevi, 20 malignant melanomas, and 10 Spitz's nevi. The nuclear pleomorphism and the maturation to the depth of the tumor were quantified by measuring nuclear area and nuclear density at serial levels of the tumor (every 220 microns of thickness). Data obtained were analyzed statistically. Linear regression was used to represent the variation of nuclear area to the depth, and the standard deviation of nuclear areas reflected nuclear pleomorphism. We attempted to separate different tumors from each other using the Jacknife procedure and morphometric data. Using the Jacknife procedure rather than the usual histological procedures, we were able to distinguish benign nevi from Spitz's nevi and malignant melanoma in as many as 92% of cases, but we distinguished Spitz's nevi from malignant melanoma in only up to 60% of cases. In conclusion, we found it difficult to distinguish between Spitz nevi and melanoma using nuclear morphometric parameters. Other studies using new morphometric parameters are needed in order to improve our ability to make this discrimination.
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PMID:Morphometric analysis of melanocytic tumors. A study of nuclear area and density. 803 Jul 66

The basic fibroblast growth factor (bFGF) is an angiogenic factor and also a mitogen for epidermal keratinocytes. In order to investigate the role of bFGF in human skin we examined the distribution of bFGF immunoreactivity in normal and diseased human skin. Antigen expression was demonstrated by direct immunofluorescence staining of cryostat sections with a polyclonal anti-bFGF antibody. In normal human skin, bFGF-like immunoreactivities were observed in the basal cells, while in the case of psoriasis, positive immunoreactivities were observed in the basal cells and several supra-basal layers at rete ridges. Seborrheic keratosis and basal cell epithelioma showed diffuse immunoreactivities in the basaloid cells of the tumor. Concurrently, benign nevus cell nevus, capillary hemangioma, squamous cell carcinoma and malignant melanoma displayed negative immunoreactivities. These results suggest that bFGF is important for basal or basaloid cell proliferation.
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PMID:Immunohistochemical localization of basic fibroblast growth factor in skin diseases. 810 71

Nestin is a newly identified intermediate filament expressed in proliferating neuronal progenitor cells, but not in the adult brain. Nestin expression reappears in many tumors of the central nervous system and has in human glioblastomas been associated with a high degree of malignancy. Because melanocytes are of neuroectodermal origin, we studied nestin expression in benign and malignant cells of the melanocytic lineage using Northern blot and immunohistochemical analyses. Nestin mRNA was detected in 24 of 34 metastatic melanomas and in 1 of 4 benign nevi, whereas the protein was expressed in 10 of 15 primary melanomas, in 29 of 34 metastatic tumors, and in 3 of 4 nevi. Neither normal melanocytes nor any of 4 basal cell carcinomas showed detectable levels of the protein. The high fraction of melanocytic tumors which express nestin, particularly the metastatic melanomas, suggests that nestin may be a useful marker for such malignancies. Furthermore, although no significant correlation between nestin expression and tumor malignancy was observed, the protein was most abundantly expressed in the infiltrating part of the tumors, indicating a possible involvement of nestin in tumor invasion.
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PMID:Expression of the neuroectodermal intermediate filament nestin in human melanomas. 827 67

Two cases of melanocytic lesions in lymph node associated with congenital naevus are presented. The first was a 30-year-old man with a nodular melanoma arising in a small congenital naevus. The second was a 2-year-old male infant with a giant congenital naevus. In both cases, naevus cell aggregates were observed in the capsule, trabeculae, perisinusoidal areas and lymphatic vessels surrounding the nodes. In the first case, clusters of large atypical melanocytes were present amongst naevus cell aggregates in the perisinusoidal areas as well as in the lymphoid parenchyma. Between the naevus cells and large atypical melanocytes, transitional forms were observed which supports the idea that the presence of large atypical melanocytes is indicative of benign naevus cells. In the second case, marginal sinuses were packed with clusters of large melanin-rich cells. Immunohistochemically, these cells were S-100 protein negative, but ultrastructural studies proved them to be melanocytes. They were considered indicative of spread of benign naevus cells via lymphatic vessels. Arrested migration of naevus cells during embryogenesis and benign spread of naevus cells are possible explanations for the histogenesis of naevus cell aggregates in lymph nodes associated with congenital naevus.
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PMID:Melanocytic lesions in lymph nodes associated with congenital naevus. 831 18

In order to evaluate a possible discriminatory diagnosis interest of HMB-45 monoclonal antibody in different melanocytic population, it was tested on 48 benign and malignant melanocytic lesions embedded in paraffin. There were made of 16 benign nevus (33%), 18 dysplastic nevus (38%) and 14 malignant melanomas (29%). The reaction was positive in 11 benign tumors (69%), 18 dysplastic nevus (100%), and 12 malignant melanomas (86%); negative in 5 dermal nevus (31%) and 2 desmoplastic melanomas (14%). We have researched, by the KHI square (chi 2) statistical test, a relation between the reaction intensity, its cutaneous location, and the tumor type. The reaction intensity is not statistically linked with the tumor type. The cutaneous location of the reaction is statistically more heterogeneous in malignant melanoma than in benign or dysplastic melanocytic lesions. Among the dysplastic nevus, 6 cases (38%), of the familial type, have an heterogeneous reaction looking like the malignant melanoma's one. However, there is no significant difference, in the reaction pattern, between dysplastic and benign lesions. Nevertheless some dysplastic nevus seems to have a phenotypic expression for HMB-45 midway between benign and malignant melanocytic lesion, that will be interesting to precise. Otherwise, the simple use and the staining of HMB-45 monoclonal antibody are of great interest to assess the depth of primary cutaneous melanoma and to diagnose secondary melanoma. However, the negativity of the spindle cell type justify the association of other markers, particularly the S100 protein, which is more sensitive, in the diagnosis of desmoplastic malignant melanoma.
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PMID:[Comparative study of HMB-45 monoclonal antibody uptake on various benign and malignant melanocytic lesions]. 836 67


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