Cases reported "Skin Neoplasms"

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1/31. Squamous carcinoma in situ of the skin containing premelanosomes, with melanocytic colonization of the tumor.

    Premelanosomes in nonmelanocytic epithelial neoplasms and "colonization" of nonmelanocytic tumors by melanocytes are two phenomena rarely documented in the literature. We report a squamous carcinoma-in-situ of skin displaying both phenomena. light microscopy showed clusters of tumor cells in the epidermis, some of which contained melanin. Dendritic melanocytes were admixed with the tumor cells. No ulceration was present. Immunoperoxidase stains for keratin showed no staining of tumor cells. Some nondendritic cells stained for HMB-45, consistent with a melanocytic lesion. Electron microscopy showed two cell types, one with desmosomes, tonofilaments, and premelanosomes and a second dendritic type with only premelanosomes. Premelanosomes were also present free in the intercellular space. These findings suggest that premelanosomes may first be discharged by melanocytes into the intercellular space and are then phagocytosed by the neoplastic cells. Thus the presence of premelanosomes in a tumor cell is not pathognomonic for melanoma or other neural crest tumors.
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2/31. A localized variant of paraneoplastic pemphigus: acantholysis associated with malignant melanoma.

    We report a 72-year-old male patient with a nodular malignant melanoma that was associated with focal suprabasal acantholysis (FSA). This phenomenon, which is regarded as an incidental finding by dermatopathologists, may be associated with inflammatory and also neoplastic skin diseases. Haematoxylin and eosin stained sections from an erythematous plaque surrounding the patient's tumour showed FSA, direct immunofluorescence (DIF) and indirect immunofluorescence (IIF) on normal human skin, monkey oesophagus and rat urinary bladder were negative. On electron microscopy few desmosomes could be detected in the basal cell layer of the acantholytic areas and there was a nearly complete loss of these structures in the spinous cell layer. Only remnants of cytoplasmic plaques and keratin filaments could be observed in those areas. In contrast, adherens junctions appeared to be well preserved. An enzyme-linked immunosorbent assay (ELISA) using recombinant fusion proteins as antigens did not show circulating autoantibodies against desmoglein 1 (Dsg1) or desmoglein 3 (Dsg3). In contrast, immunoblotting revealed autoantibodies directed against keratinocyte antigens with a molecular weight of 85 kDa and 250 kDa, the first band corresponding to the molecular weight of comigrating plakoglobin. immunoprecipitation with patient serum also revealed a 85-kDa band. We conclude that these autoantibodies, probably in conjunction with cofactors produced by the tumour, could play a part in the pathogenesis of this variant of FSA, for which we propose the term 'localized paraneoplastic pemphigus.'
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3/31. Cutaneous spindle cell carcinoma following basal cell carcinoma.

    A spindle cell carcinoma arose three years after the seeming excision of a so-called "infiltrative" basal cell carcinoma (IBCC) in the cheek of an 87-year-old Japanese woman. The patent had no history of irradiation. The tumor was composed of short fascicles and whorling arrangements of spindle to polygonal cells without residual IBCC. Immunohistochemically, the tumor was positive for vimentin, cytokeratin 8 & 18, epithelial membrane antigen, and alpha-smooth muscle actin. Ultrastructurally, the tumor cells had tonofilaments and desmosomes. The patient died after a local recurrence with metastatic lesions in the lung and the neck lymph nodes that were indicated by CT scanning and MRI at nine months after diagnosis. This case and others support the concept that spindle cell carcinoma can pursue an aggressive clinical course.
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4/31. Meningeal hamartoma of the scalp. A variant of primary cutaneous meningioma.

    A case of meningeal hamartoma of the scalp is reported. A 15-year-old girl was admitted complaining of scalp nodules in the midline occipital region. A midline skull defect was found under the nodular lesions. Histologically, the mass had a fibrocollagenous tract extending to the dura and showed an admixture of mature adipose tissue, small vessels, strands of fibrocollagenous tissue, and scattered foci of meningocytes. Immunohistochemically, the meningocytes desmosomes, interdigitating processes, and intermediate filaments. The patient's brother also had the meningeal hamartoma of the scalp. Meningeal hamartoma as a variant of primary cutaneous meningioma is extremely rare, and this is the first report of such a case in japan.
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5/31. Clear cell trichoblastoma: a clinicopathological and ultrastructural study of two cases.

    Clear cell change in basal cell carcinomas is a well-recognized phenomenon, but is obviously rare in trichoblastomas. We present two cases of clear cell trichoblastoma in which clear cell change was very much prominent, and the results of an ultrastructural study intended to explore the basis of that feature. Both our patients were women, aged 56 and 77 years, who presented with solitary, slowly growing nodules that measured 3 to 5 cm in largest dimension and were located on the scalp and the flexor aspect of the lower arm. Microscopically, the tumors in both cases were symmetric, non-ulcerated, and composed of variably sized and shaped (cribriform, racemiform, strands, cords, nodules) aggregations of monomorphous basaloid epithelial cells that were associated with a specific trichogenic stroma. Common to both tumors was clear cell cytoplasm evident in the majority of the epithelial cells in one case and almost in the entire epithelial cell population in the other. In most epithelial aggregations the epithelial cells with clear cytoplasm often appeared columnar and were arranged in a palisade along a recognizable basal membrane, thus indicative of outer sheath differentiation at the bulb. There were other signs of follicular differentiation. Ultrastructurally, variably sized clusters of uniform small basaloid epithelial cells were separated from the stroma by a thin discontinuous basement membrane. In addition to the usual organelles, the cytoplasm contained fairly conspicuous tonofilaments and variably sized vacuoles devoid of a limiting membrane, located between the palisaded nuclei and the outer cell membrane. The majority of vacuoles were empty, although clumps of a finely granular substance were occasionally evident. No distinct lipid droplets or glycogen particles were identified. The basaloid cells were joined by scattered small desmosomes. These findings were consistent with trichilemmal differentiation at the bulb.
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6/31. Merkel cell carcinoma of the head and neck associated with bowen's disease.

    The Merkel cell carcinoma occurs primarily in the skin of the head and neck, and develops in the dermis with a trabecular growth pattern. immunohistochemistry reveals positive staining for neuron-specific enolase, neurofilaments, cytokeratin and chromogranin a. Electron microscopically, the tumor cells contain dense-core granules, spinous cytoplasmic processes, desmosomes, zonulae adherentes and paranuclear filament aggregates besides frequent mitoses, focal necroses and lymphocyte and plasma cell infiltrates. The Merkel cell carcinoma is often co-existent with other malignancies such as squamous cell carcinoma or, as in the present study, with bowen's disease. The definite diagnosis of the Merkel cell carcinoma can be effected only by electron microscopic examination of the tumor.
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7/31. Ultrastructural study of cylindroma (Poncet-Spiegler tumor).

    This report describes the ultrastructural characteristics of a Poncet-Spiegler tumor (cylindroma, turban tumor). This tumor was made up of two cell types and showed a ductal differentiation. Cells bordering duct-like structures were joined together by innumerable desmosomes, especially in places where the cell membranes were markedly invaginated. The arguments in favor of an eccrine or an apocrine for the origin of this sweat gland tumor are discussed.
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8/31. Microcystic adnexal carcinoma: a light microscopic, immunohistochemical and ultrastructural study.

    We report a case of microcystic adnexal carcinoma (MAC) occurring on the upper lip of an 82-year-old woman. Microscopically the tumor showed both pilar and sweat gland differentiation, involved the entire dermis and subcutaneous tissue, and invaded perineural spaces. Immunoperoxidase studies revealed carcinoembryonic antigen to be present in the ductal lining cells and in the amorphous content in the lumen, confirming sweat gland differentiation. The S-100 protein was positive in dendritic cells within the solid cell nests, but negative in cells lining cystic spaces. Ultrastructural study confirmed that the neoplasm was composed of two components, with pilar and eccrine differentiation. The former showed concentric layers of squamous epithelial cells with well-developed desmosomes and cytofilaments. The latter had ductal and alveolar structures; the ultrastructural features included: i) numerous villous folds of plasma membrane to interdigitate each other by focal desmosomes, ii) aggregates of cytofilaments, and iii) basally located myoepithelial cells which were separated from the surrounding stroma by rather thick basement membrane. In addition, distinct amyloid deposition was also observed on ultrastructural examination. To our knowledge, amyloid deposition has not been previously reported in MAC.
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9/31. Granular cell basal cell carcinoma. A distinct histopathologic entity.

    In two cases of basal cell carcinoma with prominent granular cell features, light microscopic examination showed a tumor with the general configuration of a nodular basal cell carcinoma. Focally, there were masses of cells with eosinophilic, granular cytoplasm and large cytoplasmic inclusions, strongly suggestive of granular cell myoblastoma. Ultrastructural observations in one case showed numerous lysosome-like organelles that were similar to those described for granular cell myoblastoma, but were identical to those described for the granular cell variant of ameloblastoma, a tumor that frequently resembles basal cell carcinoma. Additional features included tonofilaments and desmosomes, both of which support an epithelial origin for the granular cells in this rare variant of basal cell carcinoma.
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10/31. Small cell carcinoma of the skin "non-Merkel cell type".

    An 81-year-old Japanese woman developed small cell carcinoma of the skin, which was different from trabecular carcinoma or neuroendocrine carcinoma of the skin. The tumor was composed of spindle-shaped or fusiform cells with scanty cytoplasm and numerous mitoses. The tumor cells were arranged in a streaming pattern and not in anastomosing trabecular fashion at all. No granules were detected by Grimelius' stain either. Immunoperoxidase staining for neuron specific enolase (NSE) did not reveal any activity. Ultrastructural study showed scanty organelles in the cytoplasm which contained a few round mitochondria, rough endoplasmic reticulum, and free polysomes. Occasionally, filamentous bundles, desmosomes, and intracytoplasmic canaliculi were recognized in the cytoplasm, but neurosecretory granules were not found throughout the cytoplasm. Electron microscopic features suggest that this tumor originated from the embryonal stratum germinativum. The present tumor can be distinguished from trabecular carcinoma or neuroendocrine carcinoma of the skin, and may be regarded as "small cell carcinoma" of the skin.
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