Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Melanotic lesions of the mucosal membranes of the head and neck have been reported infrequently. Malignant melanomas are reported with much more frequency than benign nevi in this region. The first reported case of a nevus of the middle ear mucosa is presented. The distinctions between this lesion, nevus of Ota, meningioma, Schwannoma, and hematoma are discussed. The malignant potential for this lesion is not known, but it appears low enough to obviate interval tympanotomy.
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PMID:Pigmented lesion of the middle ear: report of a case. 93 65

Four melanin pigment-containing intracranial tumors were found in three Long-Evans rats in the course of experimental oncogenesis by transplacental ethylnitrosourea (ENU). One of them was a leptomeningeal melanoma. Aside from the presence of scattered melanin-pigmented cells, the other three had the typical histological features of ENU-induced malignant nerve sheath tumors. Two of the three tumors were studied by electron microscopy and in tissue and organ culture systems. One of them demonstrated progressive melanogenesis in vitro; the other failed to produce more melanin and showed increasing differentiation, with a Schwannoma-like pattern by light microscopy. Melanosomes and premelanosomes were identified in both tumors by electron microscopy; the other fine structural features were those of malignant Schwannomas. These observations are relevant to the controversy on the histogenesis of pigmented nerve sheath tumors occasionally encountered in man and on the relationship of these tumors to pigmented nevi. The findings in the present study support the view of Masson that neoplastic nerve sheath cells are capable of melanogenesis.
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PMID:Studies on experimental malignant nerve sheath tumors maintained in tissue and organ culture systems. III. Melanin pigment and melanogenesis in experimental neurogenic tumors: a reappraisal of the histogenesis of pigmented nerve sheath tumors. 127 30

We have tested the diagnostic value in malignant melanoma of HMB45, a monoclonal antibody available for use on paraffin-embedded tissue. MATERIAL AND METHOD. Tissues tested. The following pathological tissues were tested: 10 intradermal and 11 compound naevi; 6 spitz naevi; 20 dysplastic naevi; 10 blue naevi; 2 Bednar's tumours; 6 Sutton naevi; 15 melanonychias; 21 cutaneous and 11 ocular malignant melanomas (MM), and 3 achromic metastases. Control tissues were: vitiligo (20), carcinoma (5), malignant schwannoma of the orbit (1), soft tissue sarcoma (5) and malignant lymphoma (5). Antibodies. The antibodies used were antiprotein S100, antivimentin, anticytokeratin (KL1), monoclonal antileucocyte (CD45) antibodies and HMB45, a monoclonal antibody of the IgG 1 type obtained from lymph node metastases from pigmented malignant melanomas. RESULTS. None of the control tissues were stained by the HMB Ab. Intradermal naevi did not react positively. Compound naevi: the juntional cells were stained by HMB45 in 2/10 cases. Dysplastic naevi: HMB45 showed heterogeneous reactivity of junctional cells in 15/20 cases, and this correlated with the degree of atypia. Blue naevi: HMB45 stained the superficial and deep cells in 3/10 cases. Bednar's tumour: no cell was stained by HMB45. Spitz naevi: HMB45 gave an intensely positive reaction of junctional cells in 4/5 cases and a weaker reaction of dermal cells. Sutton naevi: the naevus cells were not stained by HMB45 in 5/6 cases. In simple melanocytic hyperplasia of the nail bed, only a few atypical cells were stained. In superficially spreading melanoma (SSM) all neoplastic cells were stained by HMB45 in proportion to their degree of atypia. Residual naevus cells were negative. The anti S100 and the antivimentin antibodies stained all neoplastic and naevus cells. In nodular melanoma (NM), HMB45 stained all neoplastic cells in proportion to their degree of atypia. The antivimentin Ab stained the neoplastic cells, and so did the anti-S100 Ab which also stained inflammatory cells. In acral-lentiginous melanoma (ALM), HMB stained the dermal tumoral cells moderately and the junctional cells more strongly. In ocular melanoma, HMB45 strongly stained the fusiform cells and less strongly the epithelioid cells. In achromic metastases from cutaneous malignant melanomas, HMB45 strongly stained the neoplastic cells but did not stain the peritumoral cells. DISCUSSION. The purpose of this study was to compare the value of HMB45 with that of other immunohistochemical staining methods A. Main data from the literature. (ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:[Contribution of monoclonal antibody HMB45 in the histopathologic diagnosis of melanoma]. 170 64

Nine granular cell tumors (GCTs) were studied using the immunoperoxidase technique with a mouse monoclonal antibody to keratan sulfate and a polyclonal antibody to S-100 protein. Various lectins and basic dye stains were also employed. Schwannomas benign and a malignant, a neurofibroma, a leiomyoma, two examples of nevus pigmentosus and a congenital epulis were similarly examined to compare the histochemical reactivities. Tumor cells of all the GCTs reacted intensely with the antibodies to keratan sulfate and S-100 protein. Peripheral nerve bundles and other neurogenic tumors showed stained for S-100 protein but not for keratan sulfate. Basic dye stain indicated the presence of sulfated glycoconjugates in GCTs. Lectin stains demonstrated that GCTs were rich in glycoconjugates but the reactivity patterns for 14 lectins differed between GCTs and normal tissue components. None of the lectins used in this study was specific for GCTs. These results indicate that GCTs contain abundant glycoconjugates and that the monoclonal antibody to keratan sulfate may be an immunohistochemical marker for GCT.
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PMID:Characterization of glycoconjugates found in granular cell tumors, with special reference to keratan sulfate. 197 Jun 84

Autopsy findings of primary malignant melanoma arising in an ovarian dermoid cyst in an 86-year-old woman are presented. The right ovary was replaced by a dermoid cyst, 14 x 9 x 9 cm in size, in which several nodular tumors with diameters less than 3.2 cm were localized. They comprised diffusely proliferating anaplastic cells with prominent nucleoli. Some of them contained melanin pigments in the cytoplasm. The tumor cells were positive for S-100 protein and ultrastructurally showed melanosomes. In addition, several benign pigmented lesions resembling dermal nevus, pigmented schwannoma, or cellular blue nevus were present in the dermoid cyst, one of which contained a malignant melanomatous component. Histologic transition between benign and malignant components and the presence of another small focus of atypical melanocytes in the benign lesion suggested that the malignant melanoma arose in close association with the previously existing benign pigmented lesions in the dermoid cyst.
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PMID:Malignant melanoma arising in a dermoid cyst of the ovary. 204 57

The majority of melanocytic tumours are easily diagnosed but they become a problem when they are amelanotic and the tumour cells resemble those of other tumours. This applies particularly to secondary melanoma. Detection of S100 protein is a useful identifying marker. S100 protein, so named for its solubility in saturated ammonium sulphate, is derived from brain tissue. It is a dimer and belongs to a calcium binding group of proteins. The protein was first thought to be in neural or neural crest derived tissues but has been found in chondrocytes, adipocytes, myoepithelial cells, dendritic cells of lymphoid tissue, Langerhans cells and T lymphocytes. The protein is present in a high proportion of malignant melanomas and nevocytic nevi of skin, but is less positive in eye melanomas. It is present in gliomas, Schwannomas and neurofibromas but not in neurone derived tumours such as neuroblastomas. Chondromas, chondrosarcomas, liposarcomas, some osteogenic sarcomas and some histiocytic tumours are positive. The tumours that do not contain S100 protein are listed. Pending development of melanoma-directed monoclonal antibodies, the use of anti-serum to S100 protein plus anti-keratin and anti-leukocyte reagents is useful in the identification of tumours of doubtful histogenesis.
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PMID:S-100 protein as a marker for melanocytic and other tumours. 299 6

Aside from melanomas, other nonmelanocytic pigmented tumors synthesize melanin or contain benign passenger melanocytes. While Stage IV melanosomes (mature melanosomes) occur in neoplasms which synthesize melanin as well as in those with benign companion melanocytes, Stage II melanosomes (premelanosomes), which are found in melanocytes and cells of pigmented nonmelanocytic tumors of neural crest origin, are considered the morphologic hallmark of in vivo melanin synthesis. To test this widely held concept, we studied the ultrastructure of representative malignant melanomas and other pigmented tumors (pigmented variants of the nevocellular nevus, squamous cell carcinoma, schwannoma, basal cell carcinoma, and seborrheic keratosis). Discrete intracytoplasmic Stage II melanosomes were noted in neoplastic cells of tumors of neural crest origin (melanoma, schwannoma, and nevocellular nevus), which are widely believed to synthesize melanin. In addition, they were also detected in neoplastic epithelial cells of a squamous cell carcinoma, basal cell carcinoma, and seborrheic keratosis. In these epithelial tumors, a spectrum of melanosomes from Stage II through Stage IV were presumably acquired from nonneoplastic companion melanocytes, which were an integral part of the tumor. Because squamous epithelium has not been shown to synthesize melanin, this study suggests that the finding of intracytoplasmic Stage II melanosomes does not necessarily imply melanin synthesis. When accompanied by melanocytes, epithelial and perhaps other tumors may contain ingested Stage II melanosomes.
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PMID:The presence of stage II melanosomes (premelanosomes) in neoplasms other than melanomas. 323 89

A primary cellular blue nevus (melanocytoma) of the spinal canal in a 21-year-old woman is reported. Light microscopic examination revealed a melanotic neoplasm with histological patterns resembling schwannoma, dermal nevi, and neuroblastic-like tumor. The ultrastructural features of the neoplastic cells were similar to those in dermal blue nevi and melanomas. There was no evidence of arachnoidal cell differentiation. Immunohistochemistry revealed positive reactions for S-100 protein and neuron-specific enolase in many cells and no reactions for glial fibrillary acidic protein, cytokeratins, epithelial membrane antigen, 70-kD neurofilament protein, or Leu-7. Vimentin was strongly positive in the melanocytic cells as well as in the arachnoidal cells of involved meninges. The ultrastructural and immunohistochemical features support the nevoid nature of this tumor, which is frequently mislabeled as "melanotic meningioma."
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PMID:Cellular blue nevus ("melanocytoma") of the spinal meninges: electron microscopic and immunohistochemical features. 337 92

Melorheostosis was diagnosed in a 13 year old female. Two years later an x-ray of the skull showed an calcified intracerebral mass. At the age of 18 years the patient died. The autopsy confirmed the diagnosis of melorheostosis and revealed a meningioma of falx cerebri in close proximity to predominantly intraventricular calcified tissue. A neurinoma of the left acoustic nerve was also found. In the literature melorheostosis has been anecdotally described in combination with nevi, hemangiomas, pelvic lipoma, lipoma of the spinal cord, chondrofibromas of the median nerve, tuberous sclerosis and neurofibromatosis. The nature of the relationship between melorheostosis and neoplasms has not been clarified. Those observations as well as the present report indicate an increased frequency of tumors (particularly of the nervous system) in patients with melorheostosis.
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PMID:[The relation between melorheostosis and tumors]. 343 2

Using an immunoperoxidase method, S-100 protein was localized in 51 nonpigmented or slightly pigmented nevi, eight malignant melanomas, three neurofibromas, and one neurilemmoma of the conjunctiva. Clinico-immunohistochemical correlations are presented. Cells of these neuroectodermal tumors contain S-100 protein. Epithelial invaginations arising from the conjunctival surface and lying between melanocytes are S-100 protein-negative. This facilitates the differential diagnosis of particularly amelanotic lesions of the conjunctiva. Immunohistochemical identification of the S-100 protein represents an improvement in current histochemical differential diagnosis of these tumors.
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PMID:[S-100 protein in non-pigmented melanocytic and neuro-ectodermal tumors of the conjunctiva]. 355 17


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