1/462. Bednar tumor (pigmented dermatofibrosarcoma protuberans) occurring in a site of prior immunization: immunochemical findings and therapy.Bednar tumor is a rare pigmented variant of dermatofibrosarcoma protuberans (DFSP). Because of its rarity, information is lacking regarding the optimal therapy and potential utility of immunohistochemistry in diagnosis. We report a case of Bednar tumor in which the diagnosis was aided by immunohistochemistry for CD34, an antigen known to be expressed in DFSP but not previously reported in Bednar tumor. Our case was also striking because it represents the first reported appearance of a Bednar tumor at a site of prior immunization, a phenomenon previously noted in some cases of DFSP. The patient was treated effectively with mohs surgery and is without recurrence at 9 months.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
2/462. Reactive angioendotheliomatosis in an infant.Reactive cutaneous angioendotheliomatosis (RCA) is an uncommon benign disease characterized by intravascular proliferation of endothelial cells. The observation of RCA in infants is exceedingly rare. We describe a case of RCA in a 3-month-old infant. The lesions were characterized by six small purpuric papules (1-2 mm in diameter), distributed on the thighs and neck. The general condition of the patient was good, with no lymphadenopathy, systemic involvement, or fever. The histopathologic features of a papule were characterized by the presence of cohesive aggregates of large mononucleated cells protruding into the lumina of dilated vessels and filling some of them completely. Neither an inflammatory infiltrate nor a proliferation of pericytes were present around blood vessels. Intravascular proliferating cells demonstrated positive staining for ulex europaeus agglutinin 1 (UEA-1) and for factor viii-RA and CD34 antigens. The course of the disease was unremarkable with persistence of the lesions for 8 months; no treatment was started.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
3/462. Dendritic cell-based immunotherapy of renal cell carcinoma.dendritic cells potently stimulate antigen-specific immune responses and recent data indicate that they are also capable of eliciting antitumor immune responses. We are performing a pilot study which tests the safety and efficacy of antigen-loaded, cultured blood dendritic cells in patients with metastatic renal cell carcinoma. dendritic cells are simultaneously pulsed with lysate from autologous tumor cells and with the immunogenic protein keyhole limpet hemocyanin. During the pulse, the cells are activated with a combination of tumor necrosis factor-alpha and prostaglandin E2. patients receive 5-10 X 10(6) dendritic cells per intravenous infusion and up to six infusions at monthly intervals. The first results demonstrate that this treatment modality is very well tolerated and can be associated with strong immunological and clinical responses. The present article discusses the importance of dendritic cell maturation and the role of helper antigens in dendritic cell-based immunotherapy.- - - - - - - - - - ranking = 3keywords = antigen (Clic here for more details about this article) |
4/462. A natural cytotoxic T cell response in a spontaneously regressing human melanoma targets a neoantigen resulting from a somatic point mutation.We have studied a case of human primary melanoma displaying the classical signs of a spontaneous regression in order to characterize potentially efficient anti-tumor T cell responses. In a previous series of experiments a unique TCR Vbeta16 T cell was shown to be highly expanded at the tumor site. The corresponding clone was isolated in vitro and found to be a CD8 cytotoxic T lymphocyte with a strong and selective cytolytic activity against the autologous tumor cell line. Here, we demonstrate that this predominant Vbeta16 tumor-infiltrating lymphocyte recognizes a peptide encoded by a novel unconventional myosin class I gene. This peptide includes a mutation due to a single nucleotide substitution. The resulting Glu-->Lys replacement at position 911 of the coding sequence is critical to generate the recognized T cell epitope. These experiments demonstrate the existence of a natural tumor-specific cytolytic T cell response in a primary regressing human melanoma lesion.- - - - - - - - - - ranking = 4keywords = antigen (Clic here for more details about this article) |
5/462. A MAGE-6-encoded peptide is recognized by expanded lymphocytes infiltrating a spontaneously regressing human primary melanoma lesion.In recent years, experiments based on the in vitro stimulation of either autologous peripheral blood lymphocytes or tumor-infiltrating lymphocytes with melanoma cells have shown that distinct members of the large MAGE gene family encode tumor-associated antigenic peptides. However, little is still known about natural anti-MAGE responses in vivo. We have studied a case of spontaneously regressing human melanoma, hypothesizing that in this unique situation, the host immune system had developed an efficient cytotoxic T lymphocyte (CTL) response against the cancer cells. Amongst the dense tumor infiltrate, certain clonal populations of T cells were shown to be amplified, thereby suggesting that an antigen-driven selection had occurred at the tumor site. One of the expanded tumor-infiltrating lymphocytes was shown to be a Vbeta13 CD8 CTL displaying a strong and selective cytotoxic activity against the autologous melanoma cells. Here we show that this cytotoxic T cell clone recognizes a MAGE-6-encoded peptide. MAGE-6 is therefore the fourth gene of the MAGE family shown to encode antigenic peptide recognized by T cells. Together, these data provide further evidence that T cell responses against MAGE antigens may naturally develop in vivo.- - - - - - - - - - ranking = 4keywords = antigen (Clic here for more details about this article) |
6/462. Diagnostic relevance of chromosomal in-situ hybridization in Merkel cell carcinoma: targeted interphase cytogenetic tumour analyses.AIMS: To resolve the conflicting diagnoses of five pathologists (which included well-differentiated neuroendocrine carcinoma, malignant carcinoid, undifferentiated small-cell carcinoma, primitive neuroectodermal tumour, metastases of small-cell lung carcinoma (SCLC) and Merkel cell carcinoma (MCC)), and tumour-free lungs after necropsy, we investigated an alarmingly metastasizing MCC in a 32-year-old Caucasian man using chromosomal in-situ hybridization (CISH). Differences in incidence and course in males and females also prompted targeted analyses for chromosomes X and Y. The lesion was also analysed for p53 gene mutations. methods AND RESULTS: paraffin sections of the thorax, buccal lymph nodes and scalp tumours were stained with haematoxylin and eosin. immunohistochemistry was performed with antibodies against pancytokeratin, keratin 20, neuron-specific enolase (NSE), chromogranin, neurofilaments and vimentin, among others. Sections (5-6 microm) of the tumours were analysed with alpha-satellite probes for chromosomes 1, 6, 7, 11, 12, 17, 18, X and Y using CrSH; and exons 5-9 of the p53 gene were examined by polymerase chain reaction and single strand conformation polymorphism (PCR-SSCP) methods. Although positive for pancytokeratin, keratin 20, chromogranin, NSE, synaptophysin and vimentin, the similarity in antigen profiles expressed by SCLC and MCC prevented a definitive tumour diagnosis. Chromosomal in-situ hybridization, however, revealed trisomies 1 and 11, two frequent aberrations in MCC, and trisomy 18. Moreover, 71% of the tumour cells had two to three copies of X, whereas 98% of the cell nuclei in the hair follicles and normal epidermis (purported Merkel cell origins) displayed one x chromosome. No mutations were detected in the five exons of the p53 gene examined. CONCLUSIONS: Had CISH been performed earlier, treatment may have been tailored specifically to suit MCC, since MCC and SCLC have different therapeutic strategies. Finally, chromosome X may be of prognostic relevance in MCC, which apparently predominates in females and yet shows poorer prognosis in males, and hence be worthy of further investigation.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
7/462. Papillary formations in metastatic melanoma.Cytomorphologic features of melanoma can be extremely variable, in that they can mimic other poorly differentiated neoplasms. Ten cases of metastatic melanoma with distinct, cohesive, papillary tissue fragments observed in fine-needle aspiration (FNA) specimens are reported. These papillary fragments exhibited a central fibrovascular core with attached tumor cells, in a background of single scattered malignant cells, macrophages, and focal necrosis. The aspiration sites included regional or distant palpable lymph nodes, pancreas, bone, and skin. Nine cases had a histologic diagnosis of primary cutaneous melanoma, and in one case the primary skin tumor was detected after the diagnosis was established by FNA of the metastasis. Immunohistochemical studies (S-100 protein, HMB-45 antigen, and factor viii) were performed in four cases, and electron microscopy in one, confirming the diagnosis of melanoma. An awareness of this cytomorphologic variation of papillary formations in cytology preparations from metastatic melanoma is important and can prevent potential inaccurate interpretation.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
8/462. Microcystic adnexal carcinoma arising in the setting of previous radiation therapy.While there are several reports of microcystic adnexal carcinoma developing in patients within sites of previous therapeutic irradiation, this relationship is not well described in the dermatologic literature. We report a case of a 42-year-old man with a remote history of therapeutic irradiation following surgical resection of periorbital rhabdomyosarcoma. Subsequently, he developed multiple basal cell carcinomas and a microcystic adnexal carcinoma within the field of irradiation. The histologic features were those of a classic microcystic adnexal carcinoma, with well differentiated nests and cords of keratinocytes displaying follicular and ductular differentiation infiltrating diffusely into the reticular dermis. Dense fibrosis was present surrounding the neoplastic keratinocytes. Nuclear atypia and mitotic figures were not identified. A carcinoembryonic antigen (CEA) stain demonstrated glandular differentiation. It is important for dermatologists to be aware of the apparent relationship between the rare microcystic adnexal carcinoma with its innocuous scar-like clinical appearance and prior local radiation therapy.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
9/462. Mainly unmutated V(H) genes rearranged in B cells forming germinal centers in a cutaneous pleomorphic T-cell lymphoma.B cells in skin lesions of a pleomorphic cutaneous T-cell lymphoma with reactive germinal center hyperplasia were analyzed for their immunoglobulin V(H)DJ(H) gene rearrangements by micromanipulation and single cell polymerase chain reaction (PCR) analysis. In B lymphocytes located in germinal center-like structures, we found in 11/16 different V(H)DJ(H) rearrangements completely unmutated VH genes, suggesting that those cells did not undergo antigen-driven selection. Two V(H) genes showed more than 98% germ-line identity. In only three cells V(H) segments were somatically mutated to a higher extent, but two of these rearrangements were non-productive. These results differ markedly from what we have previously detected in B cells present in mycosis fungoides, another entity of cutaneous T-cell lymphomas where the Ig gene repertoire resembles the situation in peripheral blood with a significantly higher proportion of mutated V(H) genes. When investigating the large atypical B cells strongly expressing CD30 which were detected within the T-cell zone outside the germinal centers, we found again, in most cases, that the rearranged VH genes were completely unmutated. The B cells were of polyclonal origin. Due to this comparable Ig gene repertoire and mutational pattern, we suggest that these cells descend from the germinal center centroblasts which migrated into the T-cell zone and obviously became stimulated to express the CD30 marker. The micromanipulation technique and molecular analysis on the single cell level may provide an important input into our understanding of the mechanisms of immune regulation in cutaneous lymphomas.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
10/462. Detection of human papilloma virus type 58 in a case of a perianal bowen's disease coexistent with adult T-cell leukemia.A case of bowen's disease (BD) that appeared in the perianal region of a 65-year-old Japanese woman coexistent with chronic adult T cell leukemia (ATL) is described. Histopathological findings revealed that irregularly arranged tumor cells with atypical nuclei throughout the epidermis, which itself disclosed hyperkeratosis, dyskeratotic cells, and clumping cells. Positive staining for HPV antigens was immunohistochemically seen in several nuclei of the tumor cells. Electron microscopic study of the tumor tissue disclosed virus particles of about 50 nm in diameter form the squamous cells. A positive band at 256 bp was obtained by PCR using HPV-L1 primer. The amplified dna by L1 primer completely corresponded to that of HPV-58.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
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