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

Human Merkel cell regeneration in epidermis derived from cultured keratinocyte autografts was studied from 6 days to 6 years after transplantation. Cultured keratinocyte sheets derived from skin of the sole, axilla, groin, or scalp were transplanted to full-thickness wounds in 20 pediatric patients treated for massive burns or giant congenital nevi. Normal age- and site-matched skin as well as meshed split-thickness autografts from the same patients served as controls. Merkel cells were identified by immunohistochemistry using antibodies to cytokeratins #8 and #18. Cultured keratinocytes in vitro expressed no neuroendocrine markers, but nonspecific, simple-epithelial cytokeratin expression was observed in about 20% of cells. After transplantation, Merkel cells were identified only in cultured grafts derived from sole skin and appeared in the epidermis as early as 21 days postgrafting. Dermal Merkel cells were rarely observed, but their appearance invariably succeeded that of intraepidermal Merkel cells. Regenerated Merkel cells were never innervated, and their emergence was unrelated either spatially or temporally to epidermal reinnervation. In skin bridges of meshed split-thickness grafts, Merkel cells survived after degeneration of associated neurites, but no Merkel cells appeared within re-epithelialized interstices. Among the neuroendocrine markers tested, Merkel cells in cultured grafts, meshed skin grafts or normal pediatric skin expressed only neuron-specific enolase. They failed to stain for calcitonin, chromogranin A, Leu-7, synaptophysin, bombesin, or vasoactive intestinal polypeptide by immunohistochemistry. These findings suggest that: (a) Merkel cells derive from keratinocyte precursors which undergo neuroendocrine differentiation in the epidermis; (b) that keratinocyte stem cells are capable of undergoing Merkel cell differentiation postnatally; (c) that postnatal Merkel cell differentiation may be body-site dependent; and (d) that Merkel cell development and maintenance is independent of neural induction.
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PMID:Human Merkel cell regeneration in skin derived from cultured keratinocyte grafts. 169 32

A review was conducted of 335 malignant melanomas to identify variant morphologic patterns that might be confused with other tumors. In all, 27 predominantly amelanotic neoplasms with unusual histologic features were selected for additional study. These included nine with an adenoid or pseudopapillary pattern, seven small cell neoplasms, five with prominent myxoid stroma, four with a hemangiopericytoma-like appearance, and two composed of neoplastic cells with a signet-ring configuration. A diagnosis of melanoma was confirmed in all cases by Fontana-Masson strains for melanin pigment, electron microscopic examination, or the results of immunohistochemical analyses for cytokeratin, vimentin, S-100 protein, and the HMB-45 antigen. One tumor was associated with a congenital hairy melanocytic nevus, five were vulvovaginal lesions, four arose in the sinonasal tract, and one occurred in the rectum. Four of the specified microscopic patterns were observed in both primary and secondary neoplasms; the two signet-ring cell melanomas were recurrent lesions. The authors conclude that malignant melanomas may assume the histologic guise of adenocarcinomas, small cell carcinomas, and sarcomas, in a variety of tissue sites. Special studies designed to detect melanocytic differentiation are therefore appropriate in diverse differential diagnostic settings.
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PMID:Morphologic diversity in malignant melanomas. 224 3

An immunohistochemical study analyzing distributions of beta-subunit human chorionic gonadotropin (beta HCG), human placental lactogen (HPL), placental alkaline phosphatase (PLAP), and monoclonal anti-cytokeratin (PKK1) was undertaken to determine whether the reactivity of these antigens might assist in the differential diagnosis of molar and non-molar hydropic placentas. A total of 16 complete hydatidiform moles, 15 partial hydatidiform moles, 12 hydropic abortuses and 39 non-hydropic placentas with gestational age ranging from 4 to 40 weeks was examined. In both the complete and partial moles, many syncytiotrophoblasts stained for beta HCG, HPL, PLAP and PKK1 although the staining intensity of beta HCG in the partial moles was weak compared with the complete moles. The staining patterns in the hydropic abortuses were almost the same as those in the normal first trimester placentas and had no distinct features from the partial moles. Trophoblastic hyperplasia is an essential feature in differentiating partial moles from hydropic abortuses. With regard to the immunostaining patterns of these antibodies, there was no significant difference to enable delineation between partial and complete moles, or between a hydropic abortus and a partial mole. Monoclonal anti-cytokeratin was most sensitive for trophoblasts, but less specific for intermediate trophoblasts than HPL. Although an immunohistochemical study using antibodies against beta HCG, HPL, PLAP and PKK1 is very useful for characterizing various trophoblasts, it is considered that an immunohistochemical study may not be a suitable tool for the differential diagnosis of molar and non-molar hydropic placentas.
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PMID:Immunohistochemistry of molar and non-molar placentas with special reference to their differential diagnosis. 750 73

The apocrine nevus (AN) is a rare tumor occurring in the upper chest and the axilla. We report a case of a AN in a 33-year-old female occurring unilaterally. The presenting complaint related to tenderness and swelling in the right axilla. The initial impression was hidradenitis suppurativa. The gross specimen revealed the presence of irregular thickening just beneath the dermal subcutaneous interface. Microscopically the lesion was composed of mature apocrine glands with apical snouts. The glands were arranged in lobules divided by thin fibrous septa. Immunohistochemical studies revealed the following profile in the glandular epithelium: positive low molecular weight cytokeratin, epithelial membrane antigen, and gross cystic disease fluid protein reactivity and negative high molecular cytokeratin and S-100 protein reactivity. Carcinoembryonic antigen reactivity was found in the duct epithelium. Ultrastructural studies revealed cells lining the lumen of the glands with a concentration of granules in the apical region and light and dark granules. These findings support the previously described light microscopic observations and provide unreported ultrastructural studies in this rare tumor.
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PMID:Apocrine nevus: light microscopic, immunohistochemical and ultrastructural studies of a case. 846 22

The human ABH blood-group antigen expression of cytokeratin, S-100 protein, and the melanoma-associated antigen was studied in 12 cases of pigmented nevi. The biotin-streptavidin immunostaining system was applied. ABH antigens were found both in the endothelial cells and in the germinative epidermal layer. The flat overlaying epithelium, single melanocytes and melanoblasts were positive for cytokeratin. Some basilar cells and the giant multinucleate cells in the Spitz nevi stained for S-100 protein. The melanoma-associated antigen was visualized in the upper epidermal layers as well as in some melanocytes. The present article discusses the specificity of the antigens studied as well as some immunologic traits of potential malignant development of Spitz nevi.
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PMID:Immunohistochemical study on pigmented nevi (preliminary communication). 856 4

We present five cases of a hitherto unreported cutaneous neoplasm. The tumors appeared as solitary slow-growing flesh-colored nodules arising in young and middle-aged adults. They were located on the trunk, the upper extremities, and the face, and did not recur after complete excision. Clinically, they were diagnosed as dermal nevus, Spitz's nevus, fibroma, or neurofibroma. Histology revealed polypoid flat-dome-shaped lesions with a sharply demarcated matrix consisting of coarse hyalinized collagen bundles arranged in a prominent storiform pattern and separated by mucin-containing clefts. Despite a low overall cellularity, the tumors contained numerous, occasionally bizarre-shaped, multinucleate giant cells with crowded vesicular nuclei and a pale staining foamy cytoplasm, as well as plump fibroblastlike cells with analogous nuclear morphology. Atypical nuclei or mitotic figures were not observed. The cells were strongly positive for vimentin but negative for cytokeratin, smooth muscle actin, desmin, S-100 protein, CD34, factor XIIIa, and the macrophage markers KP1, Mac 387, and Ki-M1p, suggesting a fibroblastic origin. Based on the overall architecture, we conclude that these tumors probably represent a distinctive variant of solitary circumscribed storiform collagenoma (sclerotic fibroma) and propose the designation of giant cell collagenoma.
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PMID:Giant cell collagenoma: a benign dermal tumor with distinctive multinucleate cells. 959 25

The term Spitz's nevus refers to a large spectrum of nevi composed of spindle and/or epithelioid cells. We report on a hitherto undescribed tubular variant of a dermal epithelioid nevus, characterized by aggregates composed exclusively of cuboidal cells with the prominent feature of tubular or microcystic structures. Immunohistochemically, the epithelioid cells expressed melanocytic markers (S-100, NKI/C3) lacking markers for cytokeratin or carcinoembryonic antigen. The three-dimensional analysis of the lesions by confocal laser scanning microscopy revealed the structural configuration of tubular or microcystic empty spaces bordered by cuboidal nevus cells. This rare variant of epithelioid nevus is another example for the remarkable diversity of Spitz's nevi.
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PMID:'Tubular' epithelioid cell nevus: a new variant of Spitz's nevus. 1047 62

A seventeen-year-old Korean girl had a reddish-brown papular lesion on the nose. Histopathologically, it proved to be a "hyalinizing Spitz nevus" with the characteristic features of a discohesive growth pattern of nevus cells and hyalinized stroma. Immunohistochemical stains showed positive reactivity of nevus cells with S-100 protein and Vimentin and negative stainings with HMB45, CD68, CEA and low molecular weight cytokeratin. Hyalinizing Spitz nevus may represent a variant in the spectrum of Spitz nevus.
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PMID:Hyalinizing Spitz nevus. 1082 93

Pagetoid dyskeratosis is an incidental finding in a variety of lesions of the skin and squamous mucosa. The lesion is considered a selective keratinocytic response in which a small part of the normal population of keratinocytes is induced to proliferate in response to friction. As far as we know, pagetoid dyskeratosis has not been reported in the lips. In this article, we describe the location of the lesion in the lips and its incidence in a group of 90 unselected patients who underwent biopsy or were surgically treated for diverse labial lesions. Histochemical staining and immunohistochemical studies were performed in selected cases. Pagetoid dyskeratosis was found in 38 cases (42.2%) but only in 6 cases (6.7%) the lesion was conspicuous. There was no significant difference between the upper and the lower lip in terms of incidence of the lesion. Labial pagetoid dyskeratosis was more frequent in younger patients (46.7 +/- 25.0 versus 58.5 +/- 20.5; p < 0.05) and in women (chi(2) = 3.89; p < 0.05). Pagetoid cells were more common in suprabasal location and in the labial mucosa. These cells showed positivity for high-molecular weight cytokeratin and negative reaction for low-molecular weight cytokeratin, epithelial membrane antigen, carcinoembryonic antigen, and human papilloma virus. The immunohistochemical profile is different from the surrounding keratinocytes, indicating premature keratinization. The main differential diagnoses include white sponge nevus, leukoedema, oral koilocytoses, hairy leukoplakia, pagetoid squamous cell carcinoma in situ, and extramammary Paget's disease of the oral mucosa. The morphologic features of dyskeratotic pagetoid cells are distinctive and easily recognized as an incidental finding, thus preventing confusion with other important entities including an intraepidermal tumor.
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PMID:Pagetoid dyskeratosis of the lips. 1148 26

Multiple factors affect skin pigmentation, including those that regulate melanocyte and/or keratinocyte function. Such factors, particularly those that operate at the level of the melanosome, are relatively well characterized in mice, but the expression and function of structural and enzymatic proteins in melanocytes in human skin are not as well known. Some years ago, we generated peptide-specific antibodies to murine melanosomal proteins that proved to be instrumental in elucidating melanocyte development and differentiation in mice, but cross-reactivity of those antibodies with the corresponding human proteins often was weak or absent. In an effort to characterize the roles of melanosomal proteins in human skin pigmentation, and to understand the underlying mechanism(s) of abnormal skin pigmentation, we have now generated polyclonal antibodies against the human melanocyte-specific markers, tyrosinase, tyrosinase-related protein (TYRP1), Dopachrome tautomerase (DCT) and Pmel17 (SILV, also known as GP100). We used these antibodies to determine the distribution and function of melanosomal proteins in normal human skin (adult and newborn) and in various cutaneous pigmented lesions, such as intradermal nevi, lentigo simplex, solar lentigines and malignant melanomas. We also examined cytokeratin expression in these same samples to assess keratinocyte distribution and function. Immunohistochemical staining reveals distinct patterns of melanocyte distribution and function in normal skin and in various types of cutaneous pigmented lesions. Those differences in the expression patterns of melanocyte markers provide important clues to the roles of melanocytes in normal and in disrupted skin pigmentation.
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PMID:Production of melanocyte-specific antibodies to human melanosomal proteins: expression patterns in normal human skin and in cutaneous pigmented lesions. 1154 13


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