Epstein–Barr virus infection in B-cell Non-Hodgkin’s Lymphomas of the Oral and Maxillofacial Region: Is there any evidence?

Introduction: Epstein–Barr virus (EBV) might be an aetiological agent involved in the pathogenesis of certain Non-Hodgkin’s Lymphomas (NHLs). EBV infection has been diagnosed by serologic testing within the tumour biopsies of patients with NHL. However, the association between EBV and NHL is inconsistent with a preference for certain anatomic sites, histologic subtypes and immunosuppressed patients. The objective of this study was to characterise the B-cell NHLs of the oral cavity and maxillofacial region using histological and immunophenotypical techniques and to determine its association with EBV infection. Materials and Methods: This was a descriptive cross-sectional study that included 14 cases of B-cell NHLs of the oral cavity and maxillofacial region. The haematopoietic and lymphoid tissue tumours classification of WHO was used to categorize the cases. In-situ hybridisation for EBV–encoded RNA was performed to confirm the EBV infection. Results: The average age of the patients included in the study was found to be 48.8 ± 23 years with a higher female to male ratio (1.3:1). Our study suggested that diffuse large B-cell lymphomas (DLBCLs) and Burkitt’s lymphomas (BLs) constitute the predominant subtypes of lymphomas affecting the oral cavity and maxillofacial regions. Conclusion: The findings from our study support the view that at least a relatively smaller proportion of B-cell NHLs that occur in the oral cavity and maxillofacial region do not have a pathogenic association with EBV.

Pattern of hMLH1, hMSH2 and hMSH6 expression and clinical characteristics in a sample of Malaysian colorectal carcinoma cases

Malignant transformation from normal colonic mucosa to carcinomas may be accelerated by genetic loss or inactivation of genes of the DNA mismatch repair system. The aim of the study was to determine the local incidence and pattern of immunohistochemical expression of mismatch repair proteins namely: hMLH1, hMSH2 and hMSH6 in a series of colorectal carcinomas (CRCs) and correlate this to their clinical and pathological features. Forty-three out of 298 cases of CRCs (14.4%) showed abnormal staining pattern for mismatch repair proteins with a majority (65.1%) showing single hMLH1 loss. Tumours with mismatch repair defect (MMR-d) were frequently found at the right side of colon (p<0.001), poorly differentiated carcinomas (p<0.001), produced more mucin (p=0.007), exophytic growth (p=0.007) and were bigger (p=0.002) than tumours with no mismatch repair defect. Immunohistochemical stains for mismatch repair proteins could be done in local laboratories on these selected cases before referring for the expensive molecular test.

Lack of Rb2/p130 genetic alteration in Malaysian nasopharyngeal carcinoma

The retinoblastoma-related gene Rb2/p130 has been reported to be mutated in several malignancies such as lung cancer and Burkitt's lymphoma. Nasopharyngeal carcinoma (NPC) is a common cancer in Malaysia especially amongst the ethnic Chinese. We screened for Rb2/p130 gene (exons 19 to 21) mutations in 53 archival NPC samples via PCR-SSCP-direct sequencing approach. Only one sample had a base change which involved a serine to glycine substitution at codon 995 (S995G). We conclude that Rb2/p130 genetic alterations are infrequent in NPC and may not be essential for the pathogenesis of the disease.

Fine needle aspiration cytology of neuroendocrine carcinoma of the breast--a case report and review of literature

Neuroendocrine carcinomas of the breast are uncommon tumors known to occur in the elderly. While focal neuroendocrine differentiation may be noted in many ductal and lobular carcinomas, the term neuroendocrine carcinoma is to be applied when more than 50% of the tumor shows such differentiation. This case report details the cytological features of a neuroendocrine carcinoma that was encountered in our hospital. The fine needle aspiration (FNA) smears showed discohesive polygonal cells with abundant cytoplasm, many of which contained eosinophilic granules located at one pole. Histology of the mastectomy and axillary lymph nodes specimen from this patient showed features of neuroendocrine carcinoma--solid type, with metastasis, confirmed with immunohistochemistry. The patient is disease free seven months after surgery. This case highlights the need to closely observe cytological details to identify this rare tumor that may otherwise appear to be invasive duct carcinoma--not otherwise specified on FNA. The implications of diagnosing neuroendocrine differentiation for prognosis and management are also discussed.