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Enlarged Nuclei (enlarged + nucleus)
Selected AbstractsResistance to experimental tumorigenesis in cells of a long-lived mammal, the naked mole-rat (Heterocephalus glaber)AGING CELL, Issue 4 2010Sitai Liang Summary The naked mole-rat (NMR, Heterocephalus glaber) is a long-lived mammal in which spontaneous cancer has not been observed. To investigate possible mechanisms for cancer resistance in this species, we studied the properties of skin fibroblasts from the NMR following transduction with oncogenes that cause cells of other mammalian species to form malignant tumors. Naked mole-rat fibroblasts were transduced with a retrovirus encoding SV40 large T antigen and oncogenic RasG12V. Following transplantation of transduced cells into immunodeficient mice, cells rapidly entered crisis, as evidenced by the presence of anaphase bridges, giant cells with enlarged nuclei, multinucleated cells, and cells with large number of chromosomes or abnormal chromatin material. In contrast, similarly transduced mouse and rat fibroblasts formed tumors that grew rapidly without crisis. Crisis was also observed after > 40 population doublings in SV40 TAg/Ras-expressing NMR cells in culture. Crisis in culture was prevented by additional infection of the cells with a retrovirus encoding hTERT (telomerase reverse transcriptase). SV40 TAg/Ras/hTERT-expressing NMR cells formed tumors that grew rapidly in immunodeficient mice without evidence of crisis. Crisis could also be induced in SV40 TAg/Ras-expressing NMR cells by loss of anchorage, but after hTERT transduction, cells were able to proliferate normally following loss of anchorage. Thus, rapid crisis is a response of oncogene-expressing NMR cells to growth in an in vivo environment, which requires anchorage independence, and hTERT permits cells to avoid crisis and to achieve malignant tumor growth. The unique reaction of NMR cells to oncogene expression may form part of the cancer resistance of this species. [source] Balloon Cell Melanoma: Case ReportJOURNAL OF CUTANEOUS PATHOLOGY, Issue 1 2005Anna Yemelyanova Balloon cell melanoma (BCM) is a rare histological variant of amelanotic melanoma. The differential diagnosis of clear cell lesion includes BCM, renal cell carcinoma, clear cell sarcoma as well as a number of histiocytic and infectious processes. We report a case of BCM in a 33 year-old Indonesian man who presented with a non-tender, freely movable, non-pigmented left thigh nodule, which had been present for a year. On microscopic examination tumor consisted of a nodular infiltrate present within the dermis with superficial invasion of subcutaneous fat. Tumor cells formed nested aggregates were relatively bland in appearance and had abundant, clear cytoplasm, enlarged nuclei and prominent eosinophilic nucleoli. Rare mitotic figures were present within the deep portion of the neoplasm. No definitive nests were seen at the dermal epidermal junction or within the epidermis. Histochemical stains AFB, PAS/D, and GMS were negative. Immunoperoxidase studies were positive with antibodies to vimentin, S100, HMB45, CD68, and negative with cytokeratin, Factor XIIIA, and lysozyme. The diagnosis of BCMM was favored based on histological features, and immunoperoxidase staining pattern. We believe this case can provide additional information to help establish diagnostic criteria of this rare variant of melanoma. [source] Malignant peripheral nerve sheath tumor arising in benign ancient schwannoma: A case report with an immunohistochemical studyPATHOLOGY INTERNATIONAL, Issue 2 2000Yoshiki Mikami A rare example of malignant transformation in an ancient schwannoma arisng in the right side of the neck of a 51-year-old man without any clinical manifestations suggesting neurofibromatosis is described. The tumor, approximately 4 cm at its largest dimension, was well circumscribed and had a direct connection with the sympathetic nerve. Microscopically, the central portion of the tumor showed features of ancient schwannoma characterized by extensive hyalinization with cystic degeneration, scattered spindle cells with hyperchromatic and tapered nuclei, and some symplastic changes. However, predominantly in the outer portion, a proliferation of spindle-shaped cells with enlarged nuclei was present. The nuclei of these cells showed irregular contours, coarse granular chromatin texture, and conspicuous nucleoli. Mitotic figures and small necrotic foci with scattered apoptotic bodies were also seen. Immunohistochemically, S-100 protein was almost negative in areas consisting of overtly atypical cells where the mitotic index evaluated with MIB-1 antibody was 30.5%. In contrast, S-100-positive bland spindle cells were scattered in an extensively hyalinized area with a labeling index less than 3%. P53 protein was strongly positive in atypical spindle cells. Although it is a very uncommon event, definite nuclear atypia, frequent mitotic figures, and the existence of small necrotic foci should be recognized as indicating a diagnosis of malignant degeneration of benign schwannoma. Immunohistochemistry would be useful as an ancillary technique in such a setting. [source] Nodal marginal zone B-ceil lymphoma resembling plasmacytoma arising from a plasma cell variant of localized Castleman's diseaseAPMIS, Issue 7-8 2002a case report Nodal marginal zone B-cell lymphoma (NMZBL) occasionally represents prominent plasma cell differentiation. Recently, primary lymph node plasmacytoma has been suggested to represent an extremely plasmacytic differentiation of NMZBL. We here report a case of NMZBL showing histological features resembling plasmacytoma arising from a plasma cell variant of localized Castleman's disease (PCLCD). The patient was a 69-year-old Japanese female with a 20-year history of a right inguinal mass. Histologically, a prominent proliferation of plasma cells occupied the interfollicular area of the central portion of the lymph node, whereas centrocyte-like (CCL) cells were the main cellular component in the peripheral portion of the lymph node. Although most of the plasma cells were mature ,Marshalko-type', occasional atypical forms with enlarged nuclei were also present. The majority of the lymphoid follicles had atrophic or regressive germinal centers. A few lymphoid follicles were colonized by CCL cells. Immunohistochemistry study revealed that both plasma cells and some CCL cells had a monotypic intracytoplasmic lambda light chain. When monoclonal plasma cell infiltration is observed in PCLCD, the light chains are mostly restricted to the lambda chain. This case suggests that some plasma cell-containing tumors arising from PCLCD may represent a variant of NMZBL. [source] | ||||||||||