Differential Diagnosis of Salivary Gland Tumors: The utility of immunohistochemical markers in routine practice

OBJECTIVES : The purpose of this study is to determine whether selective immunohistochemical markers may aid in the differential diagnosis of morphologically difficult salivary gland tumors. STUDY DESIGN : The records and archival paraffin blocks of the Department of Oral Pathology and Microbiology, Tamil Nadu Government Dental College and Hospital, Chennai, South India, served as a source of material for this study. About 20 salivary gland tumors [PA (7), PLGAs (3), ACC (4), BAC (1), SDC (1), Clear cell salivary gland tumors (2) and unusual adenocarcinomas (2)] were selected from the record for the study. Formalin-fixed and paraffin embedded tissue sections of the tumors were immunohistochemically analyzed for the presence of SMA, CK, GFAP, c-kit, vimentin and S-100 protein (only in few cases). A standard streptovidin peroxidase procedure was used after antigen retrieval. To assure proper staining, salivary gland fragments, blood vessels and connective tissue fibers present in the sections adjacent to the tumor and within the tumor were used as internal positive controls. RESULTS : PAs exhibited positivity to CK in 100% of cases, vimentin in 71% of cases, SMA in 57% of cases and c-kit in 71% of cases. PLGAs were positive to CK, vimentin and c-kit in 100% of cases and to SMA in 50% of cases. ACCs showed positivity to CK in 50% of cases, vimentin in 25% of cases, SMA in 75% of cases and c-kit in 100% of cases. GFAP staining was negative in all ACCs, PLGAs and 70% of PAs. BAC exhibited reactivity to all markers except GFAP, whereas SDC was negative to all markers (CK, c-Kit, GFAP, SMA & Vimentin). CCC demonstrated positivity in 100% of cases to CK and SMA (stroma only) and in 50% of cases to vimentin, while c-kit and S-100 were negative. Unusual adenocarcinomas were positive to CK and negative to GFAP in 100% of cases, whereas 50% of cases were positive in vimentin, c-kit and SMA. Out of the two unusual adenocarcinomas S-100 was used in only one case, where it was positive. CONCLUSION : This study suggests that the use of IHC as a supplemental diagnostic tool in border line or difficult salivary gland tumors may well augment the routine microscopic differential, especially when the pattern of reaction is taken into consideration

Hemangiomatous Ameloblastoma: A Rare Variant

Ameloblastoma is a true neoplasm of enamel organ type tissue. It is the most common odontogenic neoplasm with more frequency in the mandible. A 20 years old male patient presented with a swelling in the right side of the mandible of 10 months duration. Orthopantomograph revealed multilocular radiolucency extending from the region of 46 to the condyle. Incision biopsy revealed features of plexiform ameloblastoma. Numerous vascular spaces of varying size were seen throughout the stroma. Excision biopsy also revealed similar findings. Based on these findings, a diagnosis of hemangiomatous plexiform ameloblastoma was made. Hemangiomatous ameloblastoma (HA) is still a controversial entity, with some pathologists ruling it out as a  separate lesion. This paper discusses the possibility that HA might be an aggressive variant of ameloblastoma and reviews relevant literature.&nbsp

The development and validation of a scoring tool to predict the operative duration of elective laparoscopic cholecystectomy

Background: The ability to accurately predict operative duration has the potential to optimise theatre efficiency and utilisation, thus reducing costs and increasing staff and patient satisfaction. With laparoscopic cholecystectomy being one of the most commonly performed procedures worldwide, a tool to predict operative duration could be extremely beneficial to healthcare organisations. Methods: Data collected from the CholeS study on patients undergoing cholecystectomy in UK and Irish hospitals between 04/2014 and 05/2014 were used to study operative duration. A multivariable binary logistic regression model was produced in order to identify significant independent predictors of long (> 90 min) operations. The resulting model was converted to a risk score, which was subsequently validated on second cohort of patients using ROC curves. Results: After exclusions, data were available for 7227 patients in the derivation (CholeS) cohort. The median operative duration was 60 min (interquartile range 45–85), with 17.7% of operations lasting longer than 90 min. Ten factors were found to be significant independent predictors of operative durations > 90 min, including ASA, age, previous surgical admissions, BMI, gallbladder wall thickness and CBD diameter. A risk score was then produced from these factors, and applied to a cohort of 2405 patients from a tertiary centre for external validation. This returned an area under the ROC curve of 0.708 (SE = 0.013, p  90 min increasing more than eightfold from 5.1 to 41.8% in the extremes of the score. Conclusion: The scoring tool produced in this study was found to be significantly predictive of long operative durations on validation in an external cohort. As such, the tool may have the potential to enable organisations to better organise theatre lists and deliver greater efficiencies in care

Salivary gland hybrid tumour revisited: could they represent high-grade transformation in a low-grade neoplasm?

Salivary gland hybrid tumour, first described in 1996, is a very rare neoplasm for which exact morphological criteria have not been universally agreed upon. In contrast, the concept of high-grade transformation (HGT) in salivary neoplasms has been widely accepted during the last decade, and the number of reported cases is rapidly increasing. A review of the literature revealed 38 cases of hybrid tumour reported in 22 publications. During approximately the same time period, well over 100 cases of HGT in salivary neoplasms have been reported. There are important histological similarities between hybrid tumours and salivary tumours with HGT. In the latter, containing one tumour component of low-grade malignancy and the other of high grade, the two tumour components are not entirely separated and appear to originate in the same area. Virtually, all cases reported as hybrid tumour had no clear lines of demarcation between the two tumour types. We are inclined to suggest that most of the 38 cases of hybrid tumours described in the literature would today better be called tumour with HGT rather than hybrid tumour. The relative proportion of the two components may vary, and the high-grade component is sometimes very small, which emphasises the importance of very generous sampling of the surgical specimen. The molecular genetic mechanisms responsible for HGT, including what used to be called hybrid tumour, remain largely unknown. Abnormalities of a few genes (including p53, C-MYC, cyclin D1, HER-2/neu) have been documented. As insufficient data exist on gene abnormalities in these lesions, conclusions as to whether or not they have a common origin and which mechanisms are involved in transformation cannot be drawn. Due to the small number of cases reported, many of which lack follow-up details; indicators of prognosis of hybrid tumours are not available, but their behaviour seems to be similar to that of tumours with HGT, i.e. an accelerated aggressive course. HGT of salivary gland neoplasms greatly influences macroscopic and microscopic evaluation of the specimen but also, given the high incidence of metastases and morbidity, carries significant treatment implications