A multicentre study of the precision and accuracy of the TruSlice and TruSlice Digital histological dissection devices.

BACKGROUND: Five key factors enabling a good surgical grossing technique include a flat uniformly perpendicular specimen cutting face, appropriate immobilisation of the tissue specimen during grossing, good visualisation of the cutting tissue face, sharp cutting knives and the grossing knife action. TruSlice and TruSlice Digital are new innovative tools based on a guillotine configuration. The TruSlice has plastic inserts whilst the TruSlice Digital has an electronic micrometre attached: both features enable these dissection factors to be controlled. The devices were assessed in five hospitals in the UK. MATERIAL AND METHODS: A total of 267 fixed tissue samples from 23 tissue types were analysed, principally the breast (n = 32) skin (30), rectum (28), colon (27) and cervix (17). Precision and accuracy were evaluated by measuring the defined thickness, and the consistency of achieving the defined thickness of tissue samples taken respectively. Both parameters were expressed as a total percentage of compliance for the cohort of samples accessed. RESULTS: Overall, the mean (standard deviation) score for precision was 81 (11) % whilst the accuracy score was 82 (11) % (both p < 0.05, chi-squared test), although this varied with type of tissue. Accuracy and precision were strongly correlated (rp = 0.83, p < 0.001). CONCLUSION: The TruSlice Digital devices offer an assured precision and accuracy performance which is reproducible across an assortment of tissue types. The use of a micrometre to set tissue slice thickness is innovative and should comply with laboratory accreditation requirements, alleviating concerns of how to tackle issues such as the 'measurement of uncertainty' at the grossing bench.

Pan-cytokeratin markers for rapid frozen section immunocytochemistry from head and facial Mohs cases of basal cell carcinoma: a comparison and evaluation to determine the marker of choice.

The application of immunocytochemistry in the field of Mohs micrographic surgery (MMS) is well established. This study evaluates the use of pan-cytokeratins (AE1/AE3, MNF116 and AE1/AE3+PCK26) in the assessment of basal cell carcinoma (BCC) on frozen tissue debulk specimens. Fifty-five cases of BCC, all from head and facial sites, were assessed in the study. In addition to staining all cases for the three cytokeratin antibodies under investigation, sections were also stained with haematoxylin and eosin (H&E) to demonstrate tumour architecture and morphology. All sections for immunocytochemistry were stained on a Roche Ventana BenchMark Ultra automated platform employing a rapid frozen section protocol. Results were assessed based on the intensity of staining of keratinocytes (scale: 0-100%), as well as sensitivity of staining determined by the total percentage of keratinocytes stained within the tissue section. AE1/AE3 demonstrated the most consistent staining both in terms of intensity of staining and sensitivity, with a mean of 99.1% and 99.9%, respectively. AE1/AE3+PCK26 average results indicated scores of 70.6% for intensity and 87.2% for sensitivity, with MNF116 scoring 92.9% for intensity but only 57.3% for sensitivity. The data indicate that AE1/AE3 is the best pan-cytokeratin antibody to use in the assessment of BCC in MMS. The use of cytokeratin immunocytochemistry is justified in morphologically complex cases of BCC, or in cases where dense inflammatory infiltrate surrounding any suspicious cells make identification of small numbers of tumour cells difficult to determine with just an H&E stain. The significant rationale is that cytokeratin staining is a valuable adjunct in the study of tumour cell assessment in cases of MMS for BCC. In addition, the use of anti-AE1/AE3 cytokeratin antibodies provides the most consistent staining results for such cases.