No abstract

Background Head and neck masses are a common presentation in daily practice and can be challenging to both clinicians and cytopathologists. Fine needle aspiration cytology (FNAC) is a widely used method for the diagnosis of head and neck masses. The aim of the study was to assess our institutional experience of the accuracy of FNAC in the diagnosis of head and neck masses. Methods A total of 1262 FNACs were conducted from January 2013 to December 2016 and subdivided into benign and malignant categories. The thyroid and salivary glands FNACs were classified according to the Bethesda System for Reporting Thyroid cytopathology and to the Milan System for Reporting Salivary Gland Cytopathology respectively. The measures of diagnostic accuracy of FNAC were determined taking histology as a gold standard. Results A total of 7 false negative (FN) and 6 false positive (FP) FNACs were identified. Overall sensitivity and specificity of FNAC for a malignant diagnosis were 92% and 94.4%, respectively. Accuracy of FNACs of head and neck masses was 93.5% for all sites. The salivary gland group had the highest rate of FN (2.8%). All FP were reported in the thyroid group. These cases were cytologically classified suspicious for malignancy (n = 3) and papillary carcinoma (n = 3) and proved to be lymphocytic thyroiditis on final histology. Among the most common locations, cytology of lymph nodes provided the best sensitivity (98.2%). Salivary glands as well as lymph nodes had the best specificity (100%). Conclusion FNAC of head and neck masses has a high accuracy allowing a correct therapeutic management. However, this accuracy depends on the anatomic location of the mass.

The microsatellite instability (MSI) pathway is found in most cases of hereditary nonpolyposis colorectal cancer (HNPCC) and in 12 % of sporadic colorectal cancer (CRC). It involves inactivation of deoxyribonucleic acid mismatch repair (MMR) genes MLH1, MSH2, PMS2, and MSH6. MMR germline mutation detections are an important supplement to HNPCC clinical diagnosis. It enables at-risk and mutation-positive relatives to be informed about their cancer risks and to benefit from intensive surveillance programs that have been proven to reduce the incidence of CRC. In this study, we analyzed for the first time in Tunisia the potential value of immunohistochemical assessment of MMR protein to identify microsatellite instability in CRC. We evaluate by immunohistochemistry MMR protein expression loss in tumoral tissue compared to positive expression in normal mucosa. Immunohistochemistry revealed loss of expression for MLH1, MSH2, MSH6, and PMS2 in 15, 21, 13, and 15 % of cases, respectively. Here, we report a more elevated frequency of MSI compared to data of the literature. In fact, by immunohistochemistry, 70 % of cases were shown to be MSS phenotype, whereas 30 % of cases, in our set, were instable. Moreover, according to molecular investigation, 71 % of cases were instable (MSI-H) and remaining cases were stable (29 %). Thus, we found a perfect association between MMR immunohistochemical analyses and MSI molecular investigation. Immunohistochemical analysis of MMR gene product expression may allow one to specifically identify MSI phenotype of patients with colorectal carcinomas.