The ‘tissue press’: a new device to flatten fresh tissue duringex vivoconfocal microscopy examination

Reported Outcome Measures in Mohs Micrographic Surgery in Studies With Defined Techniques for Embedding and Processing of Tissue: A Systematic Review

BACKGROUND

Mohs micrographic surgery (MMS) is a technique that combines surgical excision and histologic evaluation to achieve higher cure rates for skin cancer than traditional surgical excision. Competing performance measures have fostered numerous histologic techniques for MMS.

OBJECTIVE

To analyze differences in primary outcomes in the published literature regarding the technique of tissue processing and embedding during the MMS process.

METHODS

A systematic review was performed of the published literature in MEDLINE, PubMed, Embase, and Cochrane library that included a description of the manipulation of tissue during the grossing and embedding steps of MMS.

RESULTS

Inclusion criteria were met by 61 articles. Of these studies, the cure/recurrence rate was assessed in 1 article (1.6%), tissue conservation was assessed in 47 (77%), time-saving was assessed in 35 (57%), cost-saving was assessed in 6 (10%), and decreased artifact were assessed in 20 (33%).

CONCLUSION

There is a lack of standardization for assessing clinical outcomes in the published literature regarding MMS process techniques. Cure is a critical outcome in studies comparing MMS processing methodologies.

Slide Over: Advances in Slide-Free Optical Microscopy as Drivers of Diagnostic Pathology

Conventional analysis using clinical histopathology is based on bright-field microscopy of thinly sliced tissue specimens. Although bright-field microscopy is a simple and robust method of examining microscope slides, the preparation of the slides needed is a lengthy and labor-intensive process. Slide-free histopathology, however, uses direct imaging of intact, minimally processed tissue samples using advanced optical-imaging systems, bypassing the extended workflow now required for the preparation of tissue sections. This article explains the technical basis of slide-free microscopy, reviews common slide-free optical microscopy techniques, and discusses the opportunities and challenges involved in clinical implementation.

Ex vivo confocal microscopy: revolution in fast pathology in dermatology

Confocal microscopy with in vivo and ex vivo modalities has been used in the evaluation of skin cancer and other dermatological disorders. Recent developments in ex vivo confocal microscopy allow for faster pathology assessment with greater accuracy by the visualization of cellular and architectural details, similarly to standard pathology, in either paraffin-embedded or frozen samples. They include the possibility of multimodal confocal microscopy using different lasers and fusion images. New staining protocols including immunostaining, with no damage to conventional histopathology preparation, have been recently described in melanocytic tumours and inflammatory skin diseases. Digital staining with haematoxylin and eosin is also incorporated in the new devices. In this review the applications of ex vivo confocal microscopy will be presented with the description of the technique and the technology, clinical evidence in dermatology and other fields, and further applications.

Diagnostic accuracy of a new ex vivo confocal laser scanning microscope compared to H&E-stained paraffin slides for micrographic surgery of basal cell carcinoma

BACKGROUND

For safe excision of malignant skin tumours, complete negative surgical margins are mandatory. The gold standard for analysis is frozen sections or paraffin-embedded haematoxylin and eosin (H&E)-stained slides. The production of H&E-stained slides is time-consuming (>20 h) while wounds remain unclosed. An upcoming method is confocal laser scanning microscopy (CLSM), a technique that scans unfixed fresh tissue rapidly.

OBJECTIVE

Evaluation of the process to generate and analyse CLSM images and assessment of the accuracy to detect basal cell carcinoma (BCC) tissue.

METHODS

Digital microscopic images were generated by the Histolog Scanner v1 from 544 fresh specimens of 148 BCCs that had been stained with a 0.01% proflavine solution. CLSM images were compared to the histological diagnoses of the corresponding H&E-stained slides.

RESULTS

A total of 525 images could be analysed. The sensitivity was 73% (95% CI = [65.27%; 80.47%]), and the specificity was 96% (95% CI = [93.40%; 97.60%]). Detection of BCCs in punch biopsies was certainly detected (sensitivity of 100%). The median total time to generate and evaluate a CLSM image was 5.17 min (maximum 20.17 min and minimum 2.05 min). The greatest challenge was flattening the specimen to assure complete representation of the surgical margins.

CONCLUSION

Confocal laser scanning microscopy is a time-saving and very effective alternative to classical paraffin-embedded or frozen sections. Patient treatment could be improved due to shorter hospital stays or faster outpatient therapy due to reduced intervals between surgical stages. Diagnostic accuracy of the microscope used still must be improved.

Ex vivo confocal microscopy: an emerging technique in dermatology

This review aims to give an overview of the current available applications of ex vivo confocal microscopy (EVCM) in dermatology. EVCM is a relatively new imaging technique that allows microscopic examination of freshly excised unfixed tissue. It enables a rapid examination of the skin sample directly in the surgery room and thus represents an alternative to the intraoperative micrographic control of the surgical margins of cutaneous tumors by standard microscopic examination on cryopreserved sections during Mohs surgery. Although this technique has mainly been developed for the margin’s control of basal cell carcinoma, many other skin tumors have been studied, including melanoma. Use of EVCM is continuing to evolve, and many possible applications are under investigation, such as the study of nails and hair diseases and the diagnosis of skin infections.

Immunofluorescence and confocal microscopy for ex-vivo diagnosis of melanocytic and non-melanocytic skin tumors: A pilot study

BACKGROUND

Ex-vivo confocal laser scanning microscopy (ex-vivo CLSM) offers rapid examination of freshly excised tissue. During the conventional examination immunohistochemistry enables to distinguish various cell types. The possibility of immunofluorescent techniques could enhance the accuracy of the diagnosis performed by ex-vivo CLSM.

METHODS

The tissue probes from various skin tumors were stained with FITC-labeled S-100A10, Melan-A and anti-Ber-EP4 antibodies before examination with ex-vivo CLSM in the fluorescence and reflectance modes. Results were compared to negative controls and conventional histopathology. The staining protocols were evaluated by establishing a scoring system according to the signal intensity found in ex-vivo CLSM.

RESULTS

S100 immunostaining was successful in 55.6%. Dilution of 1:200 resulted in the best possible evaluation of the tumor. The best suitable protocol was protocol B (phosphate buffered saline [PBS], without blocking agent). Melan A immunostaining was positive in 66.7%, the best dilution was 1:500 and protocol B (PBS, without blocking agent) was the most suitable. Ber-EP4 immunostaining presented a signal in 85.7%, the best dilutions were 1:200 and 1:500 and protocol A (PBS, with blocking agent) showed most optimal results.

CONCLUSION

The use of fluorescent-labeled antibodies in ex-vivo CLSM is possible and could improve intraoperative diagnostics of skin tumors.