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Background: Skin tumors are common. Recommended treatment in most cases is surgery, with margins adapted. Except in the case of simple resection and suture, it is necessary to know the status of the margins before reconstructing the defect. A one-stage technique is possible with frozen section analysis, which gives the surgeon an intraoperative assessment of resection quality. The aim of our work is to study the reliability of the frozen section procedure., Method: A retrospective study included 689 patients who underwent surgery for skin tumor (excluding melanoma) between January 2011 and December 2019 at the University Hospital of Caen, France., Results: In 639 patients (92.75%), the frozen section analysis found healthy margins. There were 21 cases of discrepancy between the frozen section analysis and final histology. Infiltrating and scleroderma-like basal cell carcinomas showed a significantly higher frequency of affected margins on frozen section analysis (p < 0.001). The tumor size and location played a significant role in the margin status., Conclusion: In our department, the frozen section procedure is the reference examination indicating immediate flap reconstruction. The present study demonstrated its interest and overall reliability. However, it is to be used according to histologic type, size, and location., Competing Interests: Conflicts of interest None., (Copyright © 2023 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.)

The intent of this brief communication is to describe a unique incomplete staining frozen section pathology artifact encountered during Mohs Micrographic Surgery. At the authors&rsquo; institution, an amorphous, eosinophilic artifact that obscured cellular architecture was observed multiple times during histological interpretation. It was determined that incomplete tissue staining was likely caused by weak staining, possibly related to an interaction between hematoxylin dye solution and acetone. We adjusted our SLS stain line protocol by adding a 15 second water rinse between the acetone and hematoxylin pots and then compared the old fixation protocol with our new fixation protocol. This artifact, which was regularly found intraoperatively at five separate MMS laboratories has sustainably resolved. Mohs Micrographic Surgery (MMS) is a dermatologic procedure that includes tumor extirpation, tissue grossing, slide preparation, and microscopic histologic interpretation. Tissue grossing and slide preparation are vital components of the MMS procedure. There are many steps throughout tissue processing that can result in frozen section pathology artifacts. Frequently encountered frozen section pathology artifacts include vacuolation of cytoplasm or &ldquo;freeze artifact,&rdquo; overstaining and understaining with hematoxylin and eosin, incomplete dehydration, and splaying of collagen in the dermis.1-3 We describe a unique incomplete staining frozen section pathology artifact. J Drugs Dermatol. 2022;21(5):542-544. doi:10.36849/JDD.6722.

There is currently no standardised reporting format for Mohs surgery with its operation reports mostly written in a narrative form making them prone to unintentional errors and omission of necessary data. Synoptic histology reporting is used to describe excised skin cancers such as melanomas and, more recently, squamous cell and basal cell carcinomas. Since Mohs surgery is utilised as the gold standard treatment for locally invasive squamous and basal cell carcinomas, we propose the use of our model of synoptic reporting to ensure the completeness and consistency of Mohs surgery operation reports., (© 2019 The Australasian College of Dermatologists.)

Background: Mohs micrographic surgery (MMS) is the most reliable tissue-sparing technique in the management of cutaneous malignancies. Although the concept is simple, there is considerable variability in the mapping and processing techniques used by Mohs surgeons and histotechnicians., Objective: This review article aims to examine the frozen-section tissue processing techniques. Existing variations will be discussed and pearls offered to optimize the frozen processing technique., Methods: A PubMed search was performed for publications on methods of tissue processing in MMS., Results: Our review highlights variations in debulking, embedding, processing adipose tissue, cartilage, and wedge resections. We offer pearls on how to avoid false-positive and false-negative margins and discuss advances in immunohistochemistry., Conclusion: Our article provides a how-to format on the different stages of tissue processing with pearls and techniques to optimize practice and improve accuracy.

Surgical resection of nonmelanoma skin cancer (NMSC) may be performed via Mohs micrographic surgery (MMS) or standard surgical excision with complete margin analysis. Whereas MMS may necessitate delayed reconstruction surgery, intraoperative frozen section analysis (IFSA) may be used to ensure clear surgical margins before proceeding with reconstruction. To achieve curative resection while optimizing aesthetic outcomes, surgeons may use surgical excision guided by IFSA to forego extensive or delayed reconstruction. Patients undergoing wide local excision for NMSC using IFSA from October 2008 to November 2016 were evaluated. Analysis included IFSA versus permanent section outcomes, the number of required excisions, and the recurrence rate. Our analysis contained 145 patients involving 162 lesions. IFSA demonstrated that 73.4 per cent of margins were negative after one excision and 26.5 per cent were re-excised until achieving negative margins. Analysis revealed one false-positive case (0.62%) and four false-negative cases (2.47%). Nine patients had local recurrence (5.56%). Frozen section sensitivity was 88.99 per cent and specificity 99.20 per cent. The positive predictive value was 96.97 per cent, and negative predictive value was 96.90 per cent. Mean follow-up time was 39 months. Both resection and recurrence data of excised NMSC lesions at our institution suggest that surgical excision using IFSA is a safe and effective alternative to MMS.

Background and Objectives: Recent studies show that whole specimen intraoperative frozen section analysis (WIFSA) is a reliable method for margin analysis in basal cell carcinoma (BCC) and has low recurrence rates after five-years follow-up. There are no studies with longer follow-up. Our aim is to present long-term recurrence rates after WIFSA., Materials and Methods: All patients with a facial BCC receiving excision with WIFSA between 1992 and 2007 were evaluated. Recurrence rates were examined for primary BCC (pBCC), recurrent BCCs (rBCC), and the different histological subtypes. The accuracy of WIFSA was assessed by comparing with formalin-fixed paraffin-embedded section analysis., Results: A total of 1140 patients with 1265 BCCs underwent excision with WIFSA, with a median and maximum follow-up of 10 and 25.3 years, respectively. Of all tumors, 90.0% were primary. Excisions were radical after an average of 1.4 excision rounds;5, 10, and 15-year recurrence rates for pBCCs are 3.3%, 5.1%, and 7.3%, respectively. An aggressive growth pattern and rBCCs are associated with more recurrences. The accuracy of WIFSA is 98.4%., Conclusions: WIFSA provides a highly accurate analysis and has a low recurrence rate for primary BCCs. The increasing recurrence rates over time imply 5 years of follow-up may be insufficient., (© 2019 Wiley Periodicals, Inc.)

Angiomyxomas are rare soft tissue neoplasms rich in myxoid matrix and blood vessels that typically present as nodules on the trunk, head, and limbs in adults. They are classified as either cutaneous or aggressive based on histological findings and extent of local growth. There are less than 150 reported cases in the literature. In this case report we describe the first paratesticular case of a cutaneous angiomyxoma in a pediatric patient, who presented with a transilluminating paratesticular mass consistent with a hydrocele, but showed solid and vascular features on ultrasound., (Copyright © 2018. Published by Elsevier Inc.)

For squamous cell carcinoma (SCC) treated using Mohs micrographic surgery (MMS), interpretation of haematoxylin and eosin-stained frozen sections can be challenging. In these situations, ancillary use of immunostaining is a useful tool for the Mohs surgeon. However, use of immunostaining in MMS laboratories is limited, mainly because current manual immunostaining platforms are subject to operator error, and automated immunostaining, albeit accurate, is too slow for inclusion in MMS. In this report, we describe a novel 1-hour protocol for rapid frozen section immunocytochemistry, using the pancytokeratin markers AE1/AE3. This protocol has been specifically designed to integrate the speed of manual techniques and the accuracy of automated platforms, making it a valuable addition to the MMS laboratory. We propose that in selected or histologically challenging cases, there is a role for the use of this novel protocol, allowing the Mohs surgeon to more confidently declare tumour clearance, thus preventing further unnecessary surgery and preserving healthy tissue., (© 2018 British Association of Dermatologists.)

Background: Basal cell carcinomas (BCCs) excised leaving positive tumour margins, are at a higher risk of recurrence. Accordingly, complete tumour removal with preservation of healthy tissue, aiming for low recurrence rates, is the main goal in treating BCCs., Objective: The present study aimed to identify the reliability of the Whole Specimen Intraoperative Frozen Section Analysis (WIFSA) technique by comparing intraoperative WIFSA and postoperative Formalin-Fixed Paraffin-Embedded section analysis (FFPE) results in 1082 basal cell carcinomas and by assessing the recurrence rates during a follow-up period up to 10 years., Methods: A single-centre retrospective cohort of all patients with BCC of the face receiving surgical excision with the WIFSA method between January 2007 and December 2013 was evaluated. We compared the intraoperative frozen section results with postoperative FFPE in order to assess accuracy of the WIFSA. Recurrence rates were assessed among all BCCs with a tumour-free margin at final excision that had a minimum follow-up of 6 months., Results: A total of 996 patients with 1082 BCCs were treated with the WIFSA. Overall agreement of WIFSA with conventional postoperative FFPE was 98·8%, sensitivity and specificity being 99·0% and 98·7% respectively. We excluded 23 BCCs that still had positive tumour margins at the end of the procedure and another 67 for the analysis of recurrence rate because follow-up was shorter than 6 months. A total of 992 BCCs with a tumour-free margin at final excision had a mean follow-up of 5·6 years (mean 67 ± 27·7 months (range 6-117 months)). The total recurrence rate was 2·1% (21 out of 992 BCCs). The recurrence rate among the primary tumours was 1·6% (13 out of 828 cases) and 4·9% among the recurring tumours (8 out of 164 cases)., Conclusion: This study indicates that, in patients with primary or recurring BCCs, WIFSA provides a high accuracy for intraoperative specimen analysis and has a low recurrence rate after a mean follow-up of 5·6 years., Funding: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors., (Copyright © 2017 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.)

Background: In the UK, non-melanoma skin cancers (NMSCs) that are incompletely excised, recurrent or in sites high risk for incomplete excision are often offered Mohs micrographic surgery (MMS). Variations in waiting times and geographical access to MMS affect patient preference for other treatments. Our unit offers excision of such lesions under complete margin frozen section histological examination., Methods: All NMSCs excised at our unit by complete margin frozen section histological analysis from 2010 to 2014 were retrospectively reviewed. The number of excisions required, complete excision rates and recurrences to date were analysed., Results: Sixty-nine patients were treated using this technique with a total of 70 lesions excised. Approximately 71% of the excision margins were clear after primary excision, 27% at second excision and 1% at third excision. Patients had a mean follow-up of 12 months (range: 1-48) with no patients lost to follow-up and no recurrences reported to date. Ninety-eight percent of NMSC cases were completely excised and two cases were incompletely excised., Conclusion: We have found the rates of excision and recurrence of the high-risk NMSCs excised at our unit to be comparable to those reported with MMS. In addition, our data show that around 29% of patients would have had incomplete margins on primary resection, thus justifying the use of this technique in this group. We suggest that this technique is a safe and useful alternative to MMS in areas where waiting times or geographical patient preference may prohibit its use., (Copyright © 2016 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.)

Frozen section pathology is routinely used for margin assessment of non-melanoma skin cancer (NMSC). Frozen section can also be used for the primary diagnosis of several skin lesions. Limited data exist on the accuracy of frozen section in the diagnosis of NMSC. We performed a retrospective chart review of 300 cases in which frozen section diagnoses were compared with permanent section diagnoses of NMSC. Frozen section and permanent section pathology were concordant 83.3% of the time, with the highest concordance rates noted for basal cell carcinoma (145/153, 95%). Our results show a high level of concordance between frozen section and corresponding permanent section pathology diagnosis for NMSC. The rapidity of frozen section tissue processing and pathology reporting makes this technique useful in dermatologic practice for immediate diagnosis and management of NMSC. Further studies should explore strategies to decrease or eliminate discrepancies between frozen and permanent section diagnosis., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

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.

For melanoma treatment, the primary goal is complete removal with histologically negative margins. Mohs micrographic surgery (MMS) has been extensively used and studied for the treatment of nonmelanoma skin cancer, particularly at sites where tissue conservation is vital. The use of MMS for melanoma treatment has yet to become widely accepted owing to difficulties in histologic interpretation, among other factors. MMS may offer lower recurrence rates and improved survival when compared with historical controls for standard excision. Continued advances in MMS technique and immunohistochemical staining have allowed the technique to gain further support., (Published by Elsevier Inc.)

Dermatofibrosarcoma protuberans (DFSP) is a relatively uncommon tumour that arises in the dermis and underlying soft tissue. Surgical removal is the preferred treatment, with relatively wide clearance margins of 3 cm or more. Slow Mohs procedures are often employed successfully to treat patients with such tumours. Slow Mohs procedures offer the benefit of improved cure rates and maximal tissue conservation. However, dealing with such tissue successfully presents the laboratory with a host of technical problems. This report advocates a set protocol to follow for slow Mohs, based on the experience acquired from dealing with 37 cases of DFSP over a 12-year period. The report establishes the benefits of slow Mohs paraffin wax-embedded tissue over frozen sections in terms of improved morphology, tissue preservation and immunocytochemical labelling with anti-CD34.

Background: Mohs micrographic surgery offers high cure rates of nonmelanoma skin cancers with optimal sparing of normal tissue. However, it is generally more time-consuming and labour-intensive than traditional surgery. Optical coherence tomography (OCT) is an emergent technology that has the potential to diagnose basal cell carcinoma (BCC) in vivo., Objective: To compare the efficiency and accuracy of ex vivo OCT with frozen-section histology for identifying BCC in Mohs surgery., Methods: Thirty-eight patients were enrolled. After the stages were taken, images were captured with an OCT microscope and subsequently processed for standard frozen sections., Results: In total, 75 sections were scanned and the mean time to produce one OCT image was 7 min. In four of 26 positive haematoxylin-eosin sections and 23 of 49 negative sections, there was a good correlation with OCT images. The sensitivity and specificity were 19% and 56%, respectively., Conclusions: It is possible to identify BCC with ex vivo OCT and this is more rapidly obtained than with haematoxylin-eosin frozen sections. However, tumour visualization in OCT was disappointing. Practical benefit may be obtained by optimizing this technology and combining it with other new diagnostic tools., (© 2011 The Authors. BJD © 2011 British Association of Dermatologists.)

Background: Immunohistochemistry (IHC) applied to Mohs micrographic surgery (MMS) is time consuming and labor intensive, and the variability of staining quality has prevented its widespread use in clinical practice., Objective: To investigate the readability of immunostains processed by a novel automated 16-minute technique used for evaluation of frozen sections prepared during MMS for melanoma., Methods: A rapid automated instrument that performs MART-1 (melanoma antigen recognized by T cells) immunostains in 16 minutes was used to stain frozen sections and was compared with MART-1 stains of paraffin (permanent) sections, hematoxylin-eosin (H&E) stains of frozen and permanent sections from the positive or negative control specimens of the Mohs layers for melanoma. A total of 480 interpretations from 48 sections (4 types of stains for each specimen, 12 specimens read by 10 interpreters) were analyzed via blinded examination by 5 dermatopathologists and 5 Mohs surgeons at two institutions. A scoring system was used to assess the readability of each slide. Analysis of variance was used for statistical analysis., Results: In terms of clarity of interpreting melanoma sections, the 16-minute MART-1 IHC of frozen sections is equivalent to the standard MART-1 of permanent sections. The 16-minute MART-1 sections are also significantly easier to interpret than permanent sections stained with H&E for both the dermatopathologists and Mohs surgeons (P < .05)., Limitations: The study represents data collected from only two institutions in the United States., Conclusion: The rapid-stained frozen IHC sections are significantly easier to interpret than the "gold standard" permanent sections stained with H&E. This technology facilitates the rapid interpretation of melanoma in frozen sections., (Copyright © 2010 American Academy of Dermatology, Inc. Published by Mosby, Inc. All rights reserved.)

Objective: To report our experience with 200 cases of basal cell carcinoma (BCC) in 192 patients treated with an enhanced frozen-section control (FSC) technique using stereoscopic microdissection of surgical margins., Methods: Retrospective series of 192 patients with 200 lesions diagnosed as BCC of the periocular region. All were excised en bloc with 1-mm margins beyond the clinically apparent tumor and examined using an enhanced FSC technique with stereoscopic microdissection of the surgical margins., Results: Of 200 malignant BCCs, 93.0% represented primary tumors. The overall recurrence rate was 1.0%, with a mean follow-up of 4 years. In patients with primary lesions, the overall recurrence rate was 1.1%, with a mean follow-up of 3.9 years. There were no recurrences in the secondary tumor group after a mean follow-up of 4.8 years. Of the 200 lesions, 66.0% lesions required a single en bloc resection to achieve tumor-free margins., Conclusions: An enhanced FSC technique using stereoscopic microdissection of the surgical margins permits greater conservation of healthy tissue and yields cure rates comparable to those of the standard FSC technique and Mohs micrographic surgery. We believe that this enhanced FSC technique is a highly effective method for resection of periocular BCC.

Background: Dense inflammation can obscure nonmelanoma skin cancer (NMSC) on frozen sections, prompting removal of additional layers to ensure negative margins. Cytokeratin (CK) immunostaining in Mohs micrographic surgery (MMS) has been examined and found to be useful but is limited by lengthy 1-hour processing., Objective: Our objective was to develop an effective ultrarapid CK frozen section immunostain to be used during MMS in cases of NMSC with dense or perineural inflammation., Methods: An ultrarapid immunostain with a mixture of AE1/AE3 monoclonal antibodies was performed in 21 MMS cases and compared with permanent sections prepared from the same material., Results: The ultrarapid CK protocol stained all of the cells in each of the 21 examples of basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) in frozen tissue in a way equivalent to immunostains being applied to permanent sections., Conclusion: The 19-minute CK immunohistochemistry protocol in frozen tissue appears to be as effective at labeling tumor cells of SCC and BCC as methods requiring permanent sections. It is hopeful that this technique may prevent recurrences after MMS and limit the number of Mohs layers required to obtain free margins when inflammation is abundant. It also is effective in uncovering subtle perineural invasion.

Background: The use of melanoma-associated antigen recognized by T cells (MART-1) immunostain has been proposed as a useful adjunct to overcome the inherent difficulties in the use of frozen sections during Mohs surgery for the treatment of melanoma, but no studies have compared MART-1 frozen sections with MART-1 permanent sections. Current MART-1 1-hour protocols add significant time to the procedure., Objective: To determine whether there is a significant difference between frozen and permanent MART-1 immunostained sections using a rapid 19-minute protocol., Methods: Frozen and permanent sections stained with MART-1 were made from dog-ears excised during 25 reconstructions. A rapid 19-minute protocol was used to stain the frozen tissue. The sections were examined blinded, and statistical analysis was performed to analyze the data., Results: No significant difference was found in number of keratinocytes, nuclear diameter of keratinocytes, number of melanocytes, melanocytic nuclear diameter, confluence, pagetoid spread, melanocytic nesting, or atypical melanocytes., Conclusions: The 19-minute protocol is a rapid and effective MART-1 immunostain. Frozen sections stained with MART-1 provide information equivalent to that obtained from MART-1 stained permanent sections. Mohs surgeons using MART-1 can feel confident that they have the same information as they would have obtained using permanent sections using the slow Mohs method.

This article examines the different views regarding the use of frozen sections and other rapid techniques in sentinel lymph nodes from patients with cutaneous melanoma. Special attention is given to the pros and cons of such techniques.

Context: Skin cancers are the most common malignancies in this country. Treatment of these tumors often involves assessment of margins, which may be performed by frozen section., Objective: This article discusses indications for frozen section, various approaches to gross examination of specimens, Mohs micrographic surgery, diagnostic pitfalls, methods to improve diagnostic accuracy, and special techniques., Data Sources: The authors' extensive experience and review of the published literature., Conclusions: Frozen sections play a vital role in the evaluation of margins of basal cell carcinomas and squamous cell carcinomas. The role of frozen sections in evaluation of soft tissue tumors is controversial. With rare exception, they have no role in the evaluation of melanocytic tumors.

Background: Immunohistochemistry has revolutionized the use of frozen sections for the removal of melanoma., Objective: Two studies were performed to address the best and fastest way to stain melanocytes in frozen tissue sections., Materials and Methods: Fifty-six standing cones were taken from sun-damaged white skin and stained with combinations of anti-S-100, anti-HMB-45, anti-Melan-A, and azure B with appropriate controls., Results: Anti-Melan-A was the best immunohistochemical stain. Azure B stains melanin granules metachromatically green and allows differentiation of melanocytes and melanophages. Ultrarapid staining worked as well as rapid staining., Conclusion: Dako's EnVision ultrarapid staining protocol and azure B counterstain represent a dramatic improvement and should be considered the easily obtainable histologic standard when excising cutaneous melanoma.

Background: For dermatologists the preparation of frozen sections means micrographic surgery. The preparation of frozen sections is meant to be rapid, but has multiple, discrete steps that demand attention to detail., Objective: The objective was to summarize both the proven and the cutting-edge techniques of frozen section preparation., Materials and Methods: Reports from the medical literature were used to augment techniques used in our practices., Conclusion: We dissect each step of micrographic cancer removal, report on the standard and preferred methods of tissue preparation, and summarize the progress achieved in the past decade.

Background: There is significant debate over the use of frozen section processing in Mohs micrographic surgery (MMS) for melanoma. Opponents argue that individual melanocytes are too subtle to view consistently on frozen sections. On the other hand, proponents state that (1) melanocytes are visible on well-prepared frozen sections and (2) MMS using frozen sections for evaluation of melanoma surgical margins achieves comparable recurrence rates when compared with MMS using paraffin-embedded, permanent sections., Objective: To introduce a new immunohistochemical (IHC) staining protocol that consistently produces melanoma frozen section slides in 1 hour that are easily evaluated during MMS., Methods: We adapted a polymer-based IHC staining protocol to use with MMS frozen sections for the evaluation of melanoma surgical margins., Results: When used with antibody directed against MART-1 for frozen section evaluation of melanoma, the section staining is reproducible and specific for melanocytes., Conclusions: In contrast to current IHC protocols that are time consuming (2 to 2.5 hours), we present a new frozen section protocol that takes approximately 1 hour to perform. This technique benefits patients, histotechnicians, and surgeons.

Mohs micrographic surgery is a technique that offers surgeons and pathologists a means to examine the entire surgical margins of excised cutaneous malignancies in a more complete manner than conventional methods. Initially developed to treat nonmelanoma skin cancers, its use has been expanded to include histologic margin evaluation for treatment of malignant melanoma. Clinical studies demonstrate equivalent or better 5-year survival rates with Mohs surgery compared to conventional wide local excision. For surgical treatment of melanoma, it offers unique advantages for lesions requiring tissue conservation and accurate margin determination, particularly in anatomic sites where cosmetic and functional concerns are of importance (head and neck, hands, and feet), and for large or ill-defined lesions such as lentigo maligna or lentigo maligna melanoma., (Copyright 2002, Elsevier Science (USA). All rights reserved.)

High-quality RNA is essential when analyzing expression patterns of tissues by the differential display technique. However, the isolation of intact RNA can be very difficult when tissues are used that contain many RNAses or that are hard to homogenize (e.g. skin samples). We describe an improved protocol for the extraction of high-quality RNA of snap-frozen biopsies from skin tissues that works in a reproducible and reliable manner. In addition, we developed a simplified non-radioactive differential display technique using RNA from small amounts of skin samples.

Background: Dermatofibrosarcoma protuberans (DFSP) is a tumor with a high local reoccurrence rate. Mohs micrographic surgery offers the highest cure rate. However, differentiating minimal residual tumor from normal skin can be difficult during Mohs surgery., Objective: To clarify the problem of determining when a tumor-free plane had been achieved during Mohs surgery for a DFSP., Methods: In two patients with DFSPs, we compared frozen and paraffin-embedded sections extending from tumor to normal skin, using both H&E and CD34 stains., Results: On frozen, but not paraffin-embedded, sections scattered dermal spindle cells were seen in normal skin., Conclusions: Scattered dermal spindle cells in the dermis of normal skin make it difficult to differentiate minimal residual tumor from normal dermis during Mohs surgery. A biopsy of normal skin can be useful as a control in this setting.