1/113. Secondary myeloid/natural killer cell precursor acute leukemia following essential thrombocythemia.The de novo leukemic transformation of essential thrombocythemia is a rare event, and usually associated with previous treatments. We describe a patient who received treatments with nitrosourea for long-standing essential thrombocythemia and subsequently developed extramedullary tumors, tentatively diagnosed as lymphoblastic lymphoma. Combination chemotherapy was initially successful, but relapsed with marked bone marrow involvement. Surface marker analysis revealed that the tumor cells had CD5, CD7, CD33, CD34, and CD56 antigens but lacked other T-cell, and B-cell markers. Immunogenotypical studies revealed germline configurations for both T-cell receptors and immunoglobulin genes. These clinical and phenotypical features are consistent with a myeloid/natural killer cell precursor leukemia, a recently proposed distinct clinical entity. To our knowledge, this is the first report of secondary leukemia of myeloid/ natural killer cell precursor origin, and suggest that myeloid/natural killer cell precursor might be a potent target of therapy-related leukemia.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
2/113. Microcystic meningioma arising in a mixed germ cell tumor of the testis: a case report.We report a case of a microcystic variant of meningioma arising in a mixed germ cell tumor of the testis composed predominantly of mature and immature teratoma with elements of seminoma and embryonal carcinoma. We believe this is the first such case of a meningioma arising in a teratoma within a gonadal or extragonadal site. The meningiomatous component showed positive immunohistochemical staining for epithelial membrane antigen and a lack of staining for cytokeratin, factor viii, CD31, and alpha-fetoprotein. Recognition of a non-germ cell tumor arising in the setting of a teratoma in the testis may be prognostically important depending on the nature of the non-germ cell component and whether it has spread beyond the testis.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
3/113. Low-grade malignant perineurioma of the paravertebral column, transforming into a high-grade malignancy.A demarcated 6 x 5 cm right paravertebral tumor at the level of T6 in a 39-year-old male was removed surgically. Histologically, the tumor consisted of monomorphous benign-looking, low-cellular spindle cells embedded in desmoplastic stroma. Ten years later, the tumor recurred locally with metastasis to systemic organs, including the occipital skin. Malignancy was histologically evident by the increased cellularity, cellular atypia and mitotic activity. The patient died of respiratory failure at the age of 49. Retrospectively reviewed, the primary lesion was low-grade fibrosarcoma-like spindle cell tumor, with secondary transformation into a highly malignant form. The differential diagnoses included sclerosing epithelioid fibrosarcoma, low-grade fibromyxoid sarcoma and malignant peripheral nerve sheath tumor. Immunohistochemically, the spindle cells in the primary and recurrent tumors consistently expressed epithelial membrane antigen, vimentin, type 4 collagen and laminin. The tumor cells in the present case showed a differentiation toward perineurial cells, which are normally positive for these immunohistochemical markers. Hence, the appropriate diagnostic term should be 'malignant perineurioma', a subtype of malignant peripheral nerve sheath tumor.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
4/113. Middle ear adenoma with neuroendocrine differentiation.The lining of the middle ear cleft is normally a thin modified respiratory type mucosa. Normal mucosa of the middle ear is devoid of salivary type seromucous glands. Middle ear adenoma is a rare tumor that seems to be derived from the middle ear mucosa. This tumor has been previously described under a variety of names because of its different nature and biological behavior. We herein report a case of middle ear tumor that shows adenomatous and neuroendocrine features. A 64-year-old woman presented with a history of hearing loss, tinnitus and stuffy feeling of the right ear. The patient was treated two times for ear polyp. She finally underwent a tympanomastoidectomy and there was no evidence of recurrence 18 months after the procedure. Histopathological examination displayed cuboidal and columnar cells, arranged as glands, trabeculae and solid sheets. Neuroendocrine differentiation was revealed by immunohistochemical staining with polyclonal antibodies against neuron specific enolase and chromogranin antigens.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
5/113. Blastic/blastoid transformation of follicular lymphoma: immunohistologic and molecular analyses of five cases.Progression of follicular lymphoma to a higher-grade malignancy frequently heralds a poor prognosis. Clinical transformation is variably accompanied by a spectrum of histologic changes characterized by alteration in growth and cytology. Although several cytogenetic events and potential oncogenes have been documented in this progression, the underlying molecular mechanisms are largely unknown. We present five patients with an unusual histologic transformation of follicular lymphoma manifested by blastic/blastoid morphology. This transformation is histologically distinct from other types of transformation of follicular lymphoma. All five cases exhibited the t(14;18) translocation and expressed the BCL-2 protein. In addition, two of the five patients showed increased levels of the p53 protein within neoplastic cells implicating a possible role for this oncogene in blastic/blastoid transformation. The lack of BCL-1 and myeloid antigens by immunohistochemistry and flow cytometry studies served to distinguish blastic/blastoid transformation of follicular lymphoma from its morphologic mimics. This distinction is clinically important because lymphoblastic and myeloid leukemias require significantly different therapeutic modalities and show better prognosis. Moreover, the lack of Epstein-Barr virus-specific mRNA suggests that this virus is unlikely to participate in blastic/blastoid transformation of follicular lymphoma.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
6/113. Evidence for the neoplastic transformation of Von-Meyenburg complexes.Von-Meyenburg complexes (VMC) are seen frequently in the liver and are largely considered to be innocuous, with only 11 cases reported in the literature of neoplastic transformation of VMCs. The authors report three cases of cholangiocarcinoma, each occurring in a background of fibrosis and nodularity that was reported initially as micronodular cirrhosis. Although the livers showed cirrhosis, the central veins were often preserved, and regenerative activity was patchy and focal. Histologic examination revealed many VMCs, and a gradual transition from VMCs to hyperplastic or adenomatous lesions and cholangiocarcinoma. The adenomatous lesions consisted of extensive replacement of the parenchyma by tumor-like nodules of ductular proliferations without obvious features of malignancy. All three patients were older than 60 years of age and had portal hypertension. Computed tomographic scans showed multiple, small renal cysts in one patient. Immunohistochemical staining showed positivity for epithelial membrane antigen, carcinoembryonic antigen, and keratins (AE1/AE3 and CAM5.2) in tumor cells, consistent with cholangiocarcinoma. The pattern of fibrosis and nodularity in these cases is not typical of either congenital hepatic fibrosis or usual cirrhosis. The authors propose that these patients represent another aspect in the spectrum of ductal plate malformations that may be modified by other factors such as alcohol, drugs, or infection. To their knowledge, neoplastic transformation of VMCs in the background of such changes has never been reported before.- - - - - - - - - - ranking = 2keywords = antigen (Clic here for more details about this article) |
7/113. Capacity for epithelial differentiation in synovial sarcoma: analysis of a new human cell line.AIM: To analyse the capacity for epithelial differentiation in synovial sarcoma using a new human cell line. methods: A new human cell line, KU-SS-1, was established from a monophasic, spindle cell type of synovial sarcoma by grafting those cells on to severe combined immunodeficient (SCID) mice and then transferring them to in vitro culture systems. The KU-SS-1 cells were characterised by light and electron microscopy, and by immunohistochemical, flow cytometric, and cytogenetic analysis. RESULTS: Primary tumour and cultured cells at passage 20 showed a positive reaction for vimentin, which is a mesenchymal marker. After 40 passages, subcultured cells were injected into SCID mice to induce further tumours. These advanced subcultured cells and the tumour cells that they induced were positive for cytokeratin, an epithelial marker, and exhibited epithelial ultrastructural features such as intermediate junctions. Furthermore, two colour immunofluorescent analysis for proliferating nuclear cell antigen (PCNA) and intermediate filaments showed that a large number of PCNA expressing cells were positive for vimentin, and that part of this fraction also expressed cytokeratin. The existence of cells with reactivity for these three markers indicated that, in this cell line, a fraction with high proliferating capacity had both mesenchymal and epithelial markers. In addition, cytogenetically, this cell line expressed the SYT-SSX chimaeric transcript as a result of the t(X;18) (p11;q11) translocation. CONCLUSIONS: A human synovial sarcoma cell line was established and stably maintained in cell culture for more than 70 passages. In addition, this cell line showed epithelial differentiation, which supports the hypothesis that synovial sarcoma is a carcinosarcoma like tumour with true epithelial differentiation. This cell line will be a useful tool for investigating the nature of this tumour and will contribute to clinical studies.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
8/113. Sebaceous carcinoma with apocrine differentiation.A 54-year-old male had a dome-shaped and skin-colored nodule on his nose. Histopathologically, we diagnosed this neoplasm as a low-grade sebaceous carcinoma rather than a sebaceoma based on the scanning magnification and cytology. This low-grade sebaceous carcinoma was associated with glandular structures. We regarded the glandular structures as those of apocrine glandular differentiation based on 1) the histopathologic features of the glandular structures formed by columnar luminal cells with evidence of decapitation secretion; 2) the expression of cytokeratin (CK) 19, CK8, CK8/18, and CK7 in the luminal cells; 3) the positive reaction of carcinoembryonic antigen and epithelial membrane antigen on the luminal surface and in the cytoplasm of the luminal cells; and 4) the common embryologic origin of the folliculosebaceous-apocrine unit. We found CK15 expression in undifferentiated cells within the mantles of normal hair follicles, suggesting that sebaceous stem cells might exist in mantles as follicular stem cells exist in bulge areas. pluripotent stem cells in the folliculosebaceous-apocrine unit can give rise to follicular stem cells, sebaceous stem cells, and apocrine stem cells. Our patient's neoplasm showed apocrine glandular differentiation and partial immunohistochemical positivity for CK15 in the neoplastic aggregations. We believe this neoplasm originated from pluripotent stem cells destined to become sebaceous stem cells or from sebaceous stem cells, which also have the ability to differentiate within apocrine glands.- - - - - - - - - - ranking = 2keywords = antigen (Clic here for more details about this article) |
9/113. T-Cell type acute lymphoblastic leukemia following cyclosporin A therapy for aplastic anemia.Cyclosporin A (CsA) is used to prevent rejection in transplantation and to treat autoimmune and hematologic diseases such as aplastic anemia. However, the tumor growth-promoting effect of CsA remains controversial. We report the case of a 24-year-old man who developed acute lymphoblastic leukemia of precursor-T-cell origin after 75 months of treatment with CsA for aplastic anemia. The surface antigen phenotype of his leukemic cells was CD2 , CD3 , CD5 , CD7 , CD4-, CD8-, CD10-, CD20-, CD34-, CD41-, and CD56-. Southern blot analysis revealed a monoclonal rearrangement of T-cell receptor-Jgamma nongermline fragments in HindIII digestion.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
10/113. Tissue-specific expression of SV40 in tumors associated with the li-fraumeni syndrome.Inactivation of wild-type p53 tumor suppressor function is the primary mechanism of tumor initiation in li-fraumeni syndrome (LFS) individuals with germline p53 mutations. Tumors derived from LFS patients frequently retain the normal p53 allele, suggesting that alternative mechanisms in addition to gene deletion must be involved in inactivating wild-type p53 protein. dna tumor viruses, such as SV40, target p53 for inactivation through the action of viral oncoproteins. We studied the probands from two unrelated LFS families, each of whom presented with multiple malignant neoplasms. Patient 1 developed an embryonal rhabdomyosarcoma (RMS) and a choroid plexus carcinoma (CPC), while patient 2 developed a CPC and subsequently presented with both an osteosarcoma (OS) and renal cell carcinoma (RCC). We utilized DNA sequence analysis and immunohistochemistry to determine p53 gene status in the germline and tumors, as well as evidence for SV40 T-antigen oncoprotein expression. Each patient harbored a heterozygous germline p53 mutation at codons 175 and 273, respectively. In patient 1, the normal p53 gene was lost while the mutant p53 allele was reduced to homozygosity in the RMS. Both normal and mutant genes were maintained in the CPC. In patient 2, normal and mutant p53 alleles were retained in both the CPC and RCC. Both specific PCR and immunostaining detected SV40 T-antigen in both CPCs and the RCC. In addition to chromosomal alterations, epigenetic mechanisms may disrupt p53 function during tumorigenesis. In two LFS patients, we found SV40 DNA sequences and viral T-antigen expression that could account for inactivation of the normal p53 protein. Inactivation of p53 or other tumor suppressors by viral proteins may contribute to tumor formation in specific tissues of genetically susceptible individuals.- - - - - - - - - - ranking = 3keywords = antigen (Clic here for more details about this article) |
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