Background Cardiac conduction is influenced by peptidergic mechanisms as well as classic neurotransmitters. The distribution of peptide-containing nerves has not been well defined.Methods and Results Immunofluorescence and histochemical techniques were used to visualize the innervation of the human conduction system and to distinguish nerve subpopulations according to their peptide and enzyme content. Nerve fibers and fascicles displaying immunoreactivity for protein gene product 9.5 (PGP 9.5) were more numerous in the sinus and atrioventricular nodes than in the penetrating bundle, bundle branches, and adjacent myocardium. The relative density of innervation was greater in the central region of the sinus node than in the peripheral regions. Nerve densities were also higher in the transitional region of the atrioventricular node compared with its compact region. Acetylcholinesterase (AChE)-positive nerves were the main subtype identified in the sinus and atrioventricular nodes, representing half to two thirds of the stained area occu-

While the histological grade of a renal cell carcinoma is of prognostic significance there is poor concordance amongst pathologists in the use of these grading systems. Many grading systems have been described, but none has achieved widespread acceptance. The objective of this study was to assess the degree of interobserver variation amongst four experienced pathologists in their use of four commonly applied grading systems. The pathologists reviewed a series of 88 cases of renal cell carcinoma. Grades were detailed on a proforma which consisted of a breakdown of each grading system. Cohen's kappa was calculated for each pair of observers for each system. The mean kappa scores for each system were compared using the Tukey honestly significant differences method. Mean kappa was highest for the grading system of Syrjanen and Hjelt and this grading system also had a higher mean kappa than two of the other systems tested. The most striking feature of the results was the degree to which the pathologists differed in their assessments. The grading system of Syrjanen and Hjelt was shown to be subject to less interobserver variability than other commonly used classifications and we are of the opinion that it should become the standard method.

Solitary fibrous tumours are rare tumours originally described in the pleura. More recently there have been reports of these tumours arising at other sites including the parotid region. They are characterized histologically by a variety of growth patterns that can be confused by the unwary with other benign or malignant tumours particularly sarcomas. We present a case occurring in the pre-auricular region which presented diagnostic difficulties.

BackgroundFine needle aspiration biopsy (FNAB) is the tool of choice for evaluating thyroid nodules with the majority classified as benign following initial assessment. However, concern remains about false negative results and some guidelines have recommended routine repeat aspirates. We aimed to assess the utility of routine repeat FNAB for nodules classified as benign on initial biopsy and to examine the impact of establishing a multidisciplinary team for the care of these patients.MethodsWe performed a retrospective review of 400 consecutive patients (413 nodules) who underwent FNAB of a thyroid nodule at our hospital between July 2008 and July 2011. Data recorded included demographic, clinical, histological and radiological variables.ResultsThree hundred and fifty seven patients (89 %) were female. Median follow-up was 5.5 years. Two hundred and fifty eight (63 %) nodules were diagnosed as benign. The rate of routine repeat biopsy increased significantly over the time course of the study (p for trend = 0.012). Nine Thy 2 nodules were classified differently on the basis of routine repeat biopsy; one patient was classified as malignant on repeat biopsy and was diagnosed with papillary thyroid carcinoma. Eight were classified as a follicular lesions on repeat biopsy—six diagnosed as benign following lobectomy; two declined lobectomy and were followed radiologically with no nodule size increase.ConclusionsThe false negative rate of an initial benign cytology result, from a thyroid nodule aspirate, is low. In the setting of an experienced multidisciplinary thyroid team, routine repeat aspiration is not justified.