Cases reported "Carcinoma, Squamous Cell"

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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. Pulmonary carcinosarcoma: immunohistochemical and ultrastructural studies.

    A case of pulmonary carcinosarcoma in a 68-year-old male patient is reported. The tumor in the resected left upper lobe extended mainly endobronchially, invading the normal bronchial lumina and mucosa. The carcinomatous component consisted of poorly differentiated squamous cell carcinoma and was mainly located in the periphery of the tumor nests. The sarcomatous component consisted of chondrosarcoma and was mainly located in the center of the tumor nests. Tumor cells in the sarcomatous component reacted with anti-S-100 protein antibody and were surrounded with abundant homogeneous extracellular matrix staining positively with alcian blue. The transition from the carcinomatous component to the sarcomatous component appeared to be very smooth. The tumor cells in both the carcinomatous and sarcomatous components reacted with anti-epithelial membrane antigen antibody. Ultrastructurally, the tumor cells with tonofibrils in the carcinomatous component were apposed and connected to each other by desmosomes. By contrast, in the sarcomatous component, the tumor cells had well-developed and dilated rough endoplasmic reticulum and were arranged loosely in a myxomatous matrix. Some tumor cells in the sarcomatous component had occasional tonofibrils, and were apposed and connected to each other by desmosome-like structures. It is shown for the first time, ultrastructurally and immunohistochemically, that the tumor cells in the sarcomatous component of pulmonary carcinosarcomas have features of both epithelial and mesenchymal cells. It is suggested that the sarcomatous component in the present case is derived from the carcinomatous component.
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3/31. Squamous carcinoma of bladder with pseudosarcomatous stroma.

    A polypoid squamous cell carcinoma with pseudosarcomatous stroma of the urinary bladder was studied electron microscopically. The epithelial component was a typical squamous carcinoma that consisted of cells with abundant bundles of tonofilaments that converged toward well-developed desmosomes; keratohyalin granules were also seen. The stroma consisted of fusiform cells with dilated rough endoplasmic-reticulum cisternae and irregular cytoplasmic projections that were suggestive of active fibroblasts. No structures suggestive of an epithelial origin or of advanced mesenchymal differentiation were recognized. These observations are consistent with the notion that the pseudosarcomatous stroma represents a reactive process that is probably related to the growth of the epithelial neoplasm. Given the differences in behavior and prognosis between carcinomas with pseudosarcomatous stroma and true carcinosarcomas, efforts at separation of these entities are warranted.
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4/31. Spindle-cell squamous carcinoma exhibiting myofibroblastic differentiation. A study of two cases showing fibronexus junctions.

    The features of two spindle-cell carcinomas of the dermis are described with special reference to the presence of fibronexus junctions in tumour cells. The cases were of a 78-year-old man with a left eye-lid tumour and a 78-year-old woman with a naso-labial fold tumour, who had been given radiotherapy 13 years earlier for a clinically diagnosed basal cell carcinoma. Both specimens were slightly ulcerated and polypoid. Histologically, invasive tumour consisted of interlacing fascicles of plump spindled and oval cells, which were positive for several anti-cytokeratin antibodies, epithelial membrane antigen, vimentin and smooth-muscle and muscle-specific actins. Ultrastructurally, tumour cells in both cases contained rough endoplasmic reticulum (prominent in case 1), tonofibrils, desmosomes and smooth-muscle type myofilaments with focal densities. Fibronexus junctions were also present, which correlated with positive staining for fibronectin. This is the first documentation of the fibronexus in epithelial tissue in vivo, and the first unambiguous demonstration in a spindle-cell carcinoma. It extends the known distribution of the fibronexus and expands the ultrastructural spectrum of squamous carcinoma.
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5/31. Neuroendocrine carcinomas associated with squamous cell carcinomas of the uterine cervix: light and electron microscopic observations in two cases.

    Small cell carcinomas are rare in cervical cancers and appear to be a heterogeneous group of tumors. Neuroendocrine carcinoma of the cervix, one subtype of small cell carcinomas of the cervix, can be identified by characteristic light and electron microscopic criteria. Two cases of neuroendocrine carcinomas associated with squamous cell carcinomas of the uterine cervix are reported in which electron microscopic studies were performed. The presence of small dense-core membrane-bound granules (120 to 160 nm) in cytoplasmic process under electron microscopic observation confirmed the diagnosis of neuroendocrine carcinoma of the cervix. The coexistence of electron dense-core membrane-bound granules, abundant tonofibrils, and desmosomes within the cancer cells, suggests that these tumors may have derived from the multipotential precursor cells with neuroendocrine and squamous differentiation. Because neuroendocrine carcinomas appear to have the highest incidence of recurrence and the poorest prognosis, it is necessary to distinguish these neoplasms from squamous cell carcinomas of the cervix. literature about neuroendocrine carcinomas of the cervix is also reviewed.
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6/31. Primary multipotential malignant neoplasm of bone: chondrosarcoma associated with squamous cell carcinoma.

    A primary neoplasm of the proximal humerus in a 68-year-old woman was unique histologically in that it contained both malignant cartilaginous and squamous cell components. The epithelial differentiation was confirmed by the demonstration of keratin by immunohistochemical techniques and of basement membrane, tonofilaments, and well-formed desmosomes by electron microscopy. The patient died 3 1/2 years after the onset of symptoms, without clinical evidence of either a primary tumor elsewhere or metastasis. The differential diagnosis from other bone tumors with epithelial differentiation, such as adamantinoma and "primitive multipotential primary sarcoma," is discussed. This is a rare primary neoplasm of bone of unknown histogenesis. Intermutability or metaplasia between mesenchymal and epithelial tissues is a possibility. The tumor probably originated from multipotential stem cells with the ability to undergo biphasic or dual differentiation toward mesenchymal and epithelial elements.
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7/31. Polypoid squamous cell carcinoma of the larynx. An immunohistochemical study for ras p21 and cytokeratin.

    Polypoid squamous cell carcinoma of the larynx consists of two components, namely, squamous cell carcinoma and sarcomatoid spindle cells. To further investigate the histogenesis of the spindle cell component, we studied two cases of polypoid squamous cell carcinoma of the larynx by immunohistochemistry and ultrastructural analysis. Positive staining for ras oncogene p21 and cytokeratin was demonstrated in both squamous cell carcinoma and spindle cell component. Only the latter component was positive for vimentin. Electron microscopic examination showed well-developed desmosomes in spindle cells. These results suggest that the spindle cell component is epithelial in origin and malignantly neoplastic; it originates from mesenchymal metaplasia or squamous cell carcinoma.
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8/31. Primary squamous cell carcinoma of the parotid gland: a case report with electron microscopic findings.

    Primary squamous cell carcinoma of the parotid gland is a rare tumor. Histological and ultrastructural features of a primary squamous cell carcinoma arising in the right parotid gland is presented. light microscopically the tumor consisted of poorly differentiated squamous cell nests. PAS reaction was negative. Ultrastructurally the tumor cells were oval or spindle shaped and the cytoplasmic processes were frequently found. The majority of the tumor cells contained numerous intermediate filaments in their cytoplasm. No secretory granule was found. The desmosomes were well developed. It is known that mucoepidermoid carcinoma may be often misdiagnosed as squamous cell carcinoma. These findings can enable us to distinguish primary squamous cell carcinoma from mucoepidermoid carcinoma of the parotid gland.
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9/31. Malignant lymphoepithelial lesion.

    A case of undifferentiated carcinoma arising from benign lymphoepithelial lesion (BLEL) of the parotid gland was studied by light and electron microscopy. Histopathologically, the carcinoma was composed of pleomorphic anaplastic cells showing an undifferentiated type among abundant lymphoid tissue forming germinal center. Among the prominent lymphoid tissue, epithelial hyperplasia, dysplasia, and squamous metaplasia of the duct epithelium were found. Dysplastic epithelium revealed a transition with carcinomatous component in some areas. On the electron microscopic observation, the tumor cells were poorly differentiated, possessing desmosomes and intracytoplasmic filaments. The patient is alive and well 2 months after resection of the tumor, but has a high titer of serum Epstein-Barr virus capsid antigen in IgG. Eighty five cases of the malignant lymphoepithelial lesion (MLEL) including the present case are summarized.
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10/31. Electron microscopy in the diagnosis of head and neck tumors.

    Six patients with malignant head and neck tumors are shown to have required electron microscopy for accurate diagnosis. In all of these tumors, there were ultrastructural features of cytodifferentiation that were not discernible by light microscopy, such as neurosecretory granules, desmosomes, cytoplasmic processes, tonofibrils, and myofilaments. Electron microscopy is helpful in the differential diagnosis of tumors in general, but its effectiveness is particularly apparent in small-cell "undifferentiated" tumors such as neuroblastoma, rhabdomyosarcoma, Ewing's sarcoma, undifferentiated squamous-cell carcinoma of the lymphoepithelioma type, and malignant lymphoma. It has also been helpful in the identification of amelanotic melanoma and spindle-cell carcinoma.
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