To analyze the association of Epstein-Barr virus (EBV) with gastrointestinal non-Hodgkin's lymphomas arising in immunocompetent patients, 56 consecutive cases of gastrointestinal lymphomas (B-cell: 52-cases, T-cell: 3 cases, T/NK-cell: 1 case) occurring in the stomach (33 cases), intestine (22 cases) and esophagus (1 case) were investigated for the presence of EBV using polymerase chain reaction analysis as a screening method followed by EBER-1 RNA and DNA in situ hybridization (ISH) and immunohistochemistry for the expression of latent membrane protein 1 (LMP-1). Forty-seven cases demonstrated extractable DNA and EBV DNA was detected only in 4 cases. Among the, RNA (EBER-1) and DNA ISH analysis confirmed the presence of the EBV genome in tumor cells in 3 cases (T/NK-cell lymphoma of ileum, gastric high-grade B-cell lymphoma of mucosa-associated lymphoid tissue, gastric diffuse large B-cell lymphoma). Only the T/NK cell lymphoma showed diffuse positivity of tumor cells while 2 gastric B-cell lymphomas demonstrated a scattered positive reaction and no cases expressed LMP-1. Nine cases without extractable DNA by the PCR method showed no nuclear signal by EBER-1 ISH. These findings suggest that most sporadic primary gastrointestinal lymphomas in Korea are not associated with EBV.
Gastrointestinal Neoplasms/virology* ; Gastrointestinal Neoplasms/pathology ; Genome, Viral ; Herpesvirus 4, Human/isolation & purification* ; Herpesvirus 4, Human/genetics ; Human ; In Situ Hybridization ; Korea ; Lymphoma/virology* ; Lymphoma/pathology ; Polymerase Chain Reaction

OBJECTIVETo study the clinicopathologic features and immunophenotype of intraabdominal extranodal follicular dendritic cell sarcoma (FDCS) and the relationship with Epstein-Barr virus (EBV).

METHODSThe clinical and histologic features of 4 cases of FDCS were evaluated. Immunohistochemical study was performed using standard EnVision method for CD21, CD23, CD35, S-100 protein, CD68, HLA-DR, vimentin, epithelial membrane antigen, desmin, CD34 and CD117. In-situ hybridization for EBV-encoded RNA (EBER) was carried out in 2 cases.

RESULTSThe age of patients ranged from 28 to 63 years (mean=42 years). The male-to-female ratio was 3:1. The clinical presentation was abdominal discomfort, pain or mass. Radiologic examination revealed concurrent lesions in stomach and left lobe of liver in 1 patient, while non-specific intraabdominal masses were detected in the remaining cases (in which the tumor was later found to be located in the appendix, mesentery of jejunum and omentum). Two cases were misdiagnosed as gastrointestinal stromal tumor before operation. Grossly, the tumors appeared as large solid nodules, with a mean diameter of 10.8 cm. Three of the cases showed areas of necrosis. Histologically, there were plump spindle, ovoid to epithelioid cells associated with scattered multinucleated giant cells. The tumor cells were arranged mostly in storiform pattern, whorls, fascicles or solid sheets. Lymphocytic infiltrates with perivascular cuffing were noted in all cases, resulting in a distinctive biphasic pattern. Two tumors showed significant cytologic atypia, with mitotic figures (including atypical mitotic figures) readily demonstrated. The remaining case (occurring in liver) was composed of scattered large atypical cells embedded in a dense inflammatory background, mimicking inflammatory pseudotumor. Immunohistochemical study showed that all cases were positive for CD21, CD23 and vimentin. There was focal expression of CD35, S-100 protein, CD68, HLA-DR and epithelial membrane antigen. The staining for CD34 and CD117 was negative. In-situ hybridization for EBER was negative in 2 cases tested.

CONCLUSIONSIntraabdominal extranodal FDCS is extremely rare. Familiarity with its characteristic histologic features and immunophenotype is important in distinguishing the tumor from other intraabdominal spindle cell lesions (such as gastrointestinal stromal tumor). Hepatic FDCS may show inflammatory pseudotumor-like features, resulting in misinterpretation. Non-hepatic intraabdominal FDCS seems to have little association with EBV infection.

Abdominal Neoplasms ; metabolism ; pathology ; virology ; Adult ; Dendritic Cell Sarcoma, Follicular ; metabolism ; pathology ; virology ; Diagnosis, Differential ; Epstein-Barr Virus Infections ; Female ; Gastrointestinal Stromal Tumors ; pathology ; Granuloma, Plasma Cell ; pathology ; Humans ; Immunophenotyping ; Male ; Middle Aged ; Receptors, Complement 3d ; metabolism ; Receptors, IgE ; metabolism ; Vimentin ; metabolism