1/7. Follicular dendritic cell sarcoma of the colon mimicking stromal tumour.AIMS: Follicular dendritic cell tumours are very rare neoplasms that often occur in lymph nodes. We report here a case in the colon, a hitherto unreported site, in a 37-year-old female. The differentiation from gastrointestinal stromal tumour is emphasized. methods and RESULTS: The tumour was tan, elastic and solid with surface ulceration. Microscopically, it was composed of oval to spindle tumour cells with syncytial cytoplasm arranged in fascicular and whorled patterns. There were many infiltrating lymphocytes. The histological appearance resembled gastrointestinal stromal tumour, thymoma or meningioma. Distinct from the stromal tumour, the lymph node was also involved by the tumour. Immunohistochemically, the tumour cells were positive for CD21, CD35 and CD68, but negative for cytokeratin, CD34, smooth muscle actin, desmin, S100 protein, epithelial membrane antigen, leukocyte common antigen, HMB-45 and c-kit. In-situ hybridization study was negative for Epstein-Barr virus rna sequences. Ultrastructurally, the tumour cells possessed cytoplasmic processes joined by desmosomes. CONCLUSIONS: This entity should be considered in the list of differential diagnoses for gastrointestinal stromal tumour. The lymph node metastasis and immunohistochemical features are of value for identification of this rare neoplasm.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
2/7. Ulcerative colon T-cell lymphoma: an unusual entity mimicking Crohn's disease and may be associated with fulminant hemophagocytosis.Primary gastrointestinal T-cell lymphoma is uncommon. Most arise from the small intestine and are usually associated with chronic celiac disease; the so-called enteropathy associated T-cell lymphoma. Primary colon T-cell lymphoma is much more rare. We present two patients with primary colon T-cell lymphoma. Both patients had chronic diarrhea and significant weight loss. Endoscopically, the lymphoma was characterized by the presence of multiple skipped ulcers distributed from the terminal ileum to the descending colon. It was differentiated from Crohn's disease by the absence of fistula or thickening of the intestinal walls. Histologically, the lymphoma was composed of medium to large atypical cells located in the ulcer base with extension to the muscular layer and the adjacent atrophic mucosa. Occasional increased intraepithelial lymphocytes were also seen. Immunohistochemically, the lymphoma cells and intraepithelial lymphocytes were CD3 , CD4-, CD56- and CD8-. It was difficult to diagnosis this unusual lymphoma by biopsy. Because most biopsy specimens showed mixed inflammation within which the lymphoma cell was sometimes hard to identify. Both patients died of fulminant hemophagocytic syndrome and Epstein-Barr virus genome was detected in the lymphoma cells using in situ hybridization on the final surgical specimens. Our study indicates that it is important to recognize this ulcerative colon T-cell lymphoma and to differentiate it from inflammatory bowel disease because of its much more aggressive clinical behavior.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
3/7. Chromosomal gains at 9q characterize enteropathy-type T-cell lymphoma.Genetic alterations in enteropathy-type T-cell lymphoma (ETL) are unknown so far. In this series, 38 cases of ETL were analyzed by comparative genomic hybridization (CGH). CGH revealed chromosomal imbalances in 87% of cases analyzed, with recurrent gains of genetic material involving chromosomes 9q (in 58% of cases), 7q (24%), 5q (18%), and 1q (16%). Recurrent losses of genetic material occurred on chromosomes 8p and 13q (24% each), and 9p (18%). In this first systematic genetic study on ETL, chromosomal gains on 9q (minimal overlapping region 9q33-q34) were found to be highly characteristic of ETL. fluorescence in situ hybridization analysis on four cases of ETL, using a probe for 9q34, indicated frequent and multiple gains of chromosomal material at 9q34 (up to nine signals per case). Among 16 patients with ETL who survived initial disease presentation, patients with more than three chromosomal gains or losses (n = 11) followed a worse clinical course than those with three or less imbalances (n = 5). The observation of similar genetic alterations in ETL and in primary gastric (n = 4) and colonic (n = 1) T-cell lymphoma, not otherwise specified, is suggestive of a genetic relationship of gastrointestinal T-cell lymphomas at either localization.- - - - - - - - - - ranking = 2keywords = hybridization (Clic here for more details about this article) |
4/7. A biologically active parathyroid hormone-like substance secreted by an adenosquamous carcinoma of the transverse colon.Recently, controversy has emerged as to whether paraneoplastic hypercalcemia in nonparathyroid tumors is due to ectopic production of a parathyroid hormone (PTH)-like substance. A sensitive dna hybridization technique was unable to reveal PTH mRNA in a collection of such tumors. However, there is growing evidence that squamous differentiation of tumors favors the expression of PTH-like substances. We report the case of a 41-year-old woman with an adenosquamous carcinoma of colonic origin associated with severe hypercalcemia. The squamous component of liver metastases showed immunoreactivity with two different PTH antisera, suggesting the production of a PTH-like substance.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
5/7. Molecular genetic analysis demonstrates that multiple posttransplantation lymphoproliferative disorders occurring in one anatomic site in a single patient represent distinct primary lymphoid neoplasms.BACKGROUND. Posttransplantation lymphoproliferative disorders (PT-LPDs) are a clinicopathologically heterogeneous group of lymphoid proliferations of varied clonal composition, the majority of which are associated with Epstein-Barr virus (EBV) infection. The clonal content and clonal relatedness of 24 separate PT-LPD lesions occurring synchronously in one organ in a single patient were investigated. methods. Twenty-four separate PT-LPD lesions from the colon and mesentery of a 15-year-old male, developing 4 months after cardiac transplantation, were studied for clonality based on immunoglobulin heavy chain (IgH) gene rearrangements for the presence, clonality, and type of EBV infection and for the presence of c-myc, ras, and p53 gene alterations. Southern blot hybridization, polymerase chain reaction, and single strand conformation polymorphism assays were employed. RESULTS. All 24 lesions were histologically similar (polymorphic B-cell lymphomas) but exhibited varied clonality and were clonally distinct with respect to both IgH gene rearrangements and EBV infection. All lesions were infected with EBV type A. Structural alterations of oncogenes or tumor suppressor genes were not identified. CONCLUSIONS. Separate PT-LPD lesions occurring synchronously in a single organ or patient may be clonally distinct, suggesting that they represent multiple distinct primary lymphoid proliferations rather than metastatic disease as in conventional malignant lymphomas. This may explain partially the rapid development in some patients of a large PT-LPD tumor burden that may regress rapidly after reduction of immunosuppression.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
6/7. The association of Epstein-Barr virus with smooth-muscle tumors occurring after organ transplantation.BACKGROUND. Epstein-Barr virus (EBV) has been associated with nasopharyngeal carcinoma, some lymphomas, and lymphoproliferative disease after organ transplantation. Many lymphoproliferative tumors that occur after transplantation are clonal, a property that classifies them as neoplastic. Clonality can be determined by analysis of the extrachromosomal circular dna episomes produced by EBV infection. methods. We describe three young children in whom smooth-muscle tumors developed 18 months to 5 1/2 years after liver transplantation with immunosuppression. We examined the tumors by microscopy and with immunohistochemical studies and molecular genetic analyses of the EBV dna. RESULTS. The tumors were composed of spindle cells with smooth-muscle features and resembled those described in patients with the acquired immunodeficiency syndrome. Immunohistochemical analysis was negative for EBV latent membrane protein and EBV receptor (CD21), but positive for EBV nuclear antigen 2. In situ hybridization revealed nuclear EBV sequences, and molecular genetic analysis showed the EBV genome to be clonal in all three patients. CONCLUSIONS. Smooth-muscle tumors that developed after organ transplantation contained clonal EBV, suggesting that the virus has a role in the development of these neoplastic lesions.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
7/7. Localization of Epstein-Barr virus genome in lymphoid cells in poorly differentiated adenocarcinoma with lymphoid stroma of the colon.Poorly differentiated adenocarcinoma with lymphoid stroma occurred in the transverse colon of a 77 year old female. Numerous small lymphocytes and plasma cells were distributed in the tumor stroma. Non-isotopic in situ hybridization study for Epstein-Barr (EBV)-related small nuclear rna (EBER-1) revealed positive signals in the nuclei of a few lymphocytes in the tumor stroma, while the tumor cell nuclei were not labeled. Immunostaining for latent membrane protein-1 was negative. The significance of detection of the EBV-infected lymphocytes in the colon tumor stroma is discussed.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |