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Purpose: This study was a retrospective and nonrandomized study to assess the safety and reliability of identifying the surgical margin in breast cancer breast-conserving surgery (BCS) by using intraoperative ultrasonic location and specimen mammography instead of traditional intraoperative frozen pathological section., Methods: Among the patients who underwent BCS from May 2019 to October 2021, according to the different methods of evaluating the intraoperative margin, 104 breast cancer patients were included in the frozen edge group, 53 breast cancer patients were included in the freeze-free group, and the surgeon judged whether extended resection was needed based on the results of pathological section or evaluation of intraoperative ultrasound and mammography. The surgical margins of the two groups were judged by postoperative pathological results as the gold standard., Results: The median waiting pathology results time in the frozen edge group was 64 minutes, while the waiting time in the freeze-free group was 30 minutes, and the difference was statistically significant (P < .0001). The postoperative pathological results showed that the positive rate of the surgical margin in the frozen edge group was 0.96%. The coincidence rate of intraoperative frozen and postoperative pathological results was 99.04%. The coincidence rate between intraoperative mammography and postoperative pathological results was 100%., Conclusions: In BCS, the method of using intraoperative staining markers combined with mammography to evaluate the resection margin is highly accurate, reliable, economical and convenient, and at the same time reduces the waiting time of the operator during the operation. However, this was not a randomized controlled study, and there was patient selection bias, and its safety needs to be confirmed by long-term follow-up. In the future, it is expected to become the mainstream means of evaluating., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

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.)

Background: Frozen section is a time- and labor-intensive method for intraoperative pathologic diagnosis. As a result, there exists a need to expedite and streamline the acquisition and interpretation of diagnostic histologic data to inform surgical decision making. Stimulated Raman histology (SRH) is an emerging technology that may serve to expedite the acquisition and interpretation of histologic data in the operating room., Methods: A blinded, prospective cohort study of 82 patients undergoing resection for tumors of the central nervous system was performed. Twenty-six patients with diagnoses of meningioma on SRH, frozen, or permanent section were included in this subanalysis. Diagnostic time and accuracy of stimulated SRH histology images were compared with the gold standard (frozen section). Agreement of SRH and frozen section diagnosis with permanent section (true) diagnosis was also compared., Results: Mean time-to-diagnosis was significantly shorter for SRH-mediated diagnosis compared with frozen section (9.2 vs. 35.8, P < 0.0001). Diagnostic accuracy was not significantly different between methods (P = 0.15). Diagnostic agreement was not significantly different between SRH versus frozen, SRH versus permanent, or frozen versus permanent section methods (P = 0.5, P = 0.5, P = 1.00)., Conclusions: SRH is a promising adjuvant technology that may expedite intraoperative neuropathologic consult without sacrificing diagnostic accuracy., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background: Our previous study revealed that intraoperative frozen section (FS) analysis could differentiate invasive lung adenocarcinoma (LUAD) accurately from preinvasive lesions. However, few articles have analyzed the clinical impact of FS errors such as underestimation of invasive adenocarcinomas (IACs), and whether complementary therapy is needed remains controversial., Research Question: What is the prognosis of patients undergoing limited resection for invasive LUAD misdiagnosed as atypical adenomatous hyperplasia (AAH), adenocarcinoma in situ (AIS), or minimally invasive adenocarcinoma (MIA) by intraoperative FS analysis?, Study Design and Methods: From 2012 through 2018, data on 3031 patients undergoing sublobar resection of AAH, AIS, or MIA diagnosed by FS analysis were collected. The concordance rate between FS analysis and final pathologic results was evaluated. To assess the clinical significance of a discrepancy between FS and final pathologic results, patients with final pathologic results of IAC were identified for prognostic evaluation., Results: When AAH, AIS, and MIA were classified together as a group, the overall concordance rate between FS and final pathologic results was 93.7%, and 192 patients (6.3%) received an upgraded diagnosis from the final pathologic results. Misdiagnosed IACs consisted of 94 patients (48.9%) with lepidic-predominant adenocarcinoma, 77 patients (40.1%) with acinar predominant adenocarcinoma, 19 patients (9.9%) with papillary predominant adenocarcinoma, one patient with solid predominant adenocarcinoma, and one patient with invasive mucinous adenocarcinoma. Among these patients, no positive N1 or N2 lymph node findings were observed. Moreover, the 5-year recurrence-free survival was still 100%, although the final pathologic results turned out to be IAC., Interpretation: Patients undergoing limited resection of invasive LUAD misdiagnosed as AAH, AIS, or MIA by FS analysis showed excellent prognoses. Sublobar resection guided by FS diagnosis would be adequate for these underestimated cases of invasive LUAD., (Copyright © 2020 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.)

MicroRNAs (miRNAs) are key regulators of gene expression at the posttranscriptional level. Precisely profiling of miRNA expression will help us to better understand their roles in normal and diseased cells and tissues. Here we describe in situ miRNA detection by padlock probing and miRNA target-primed rolling circle amplification. We optimized our protocol and showed it can be applied to both fixed cells and tissue sections. The method can be used in basic research and potentially in clinical diagnostics in the future., Competing Interests: Declaration of competing interest The authors declare no conflict of interest., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Objective: Histologic types and grades are critical in the diagnosis and treatment of spinal tumors. Intraoperative frozen section is a fast and easy method in confirming pathologic diagnosis during the operation. This study was undertaken to reveal the accuracy of intraoperative frozen section biopsy in order to make proper treatment plans., Methods: This retrospective study concerned patients who underwent spinal tumor surgeries from 1 January, 2012 to 31 December, 2016. Frozen section biopsy and permanent biopsy were compared, and cases that had differences were counted., Results: Thirty-seven cases out of 324 patients had discrepancies (11.4%). In discrepant cases 11 cases were ependymoma (29.7%) and 6 cases were schwannoma (16.2%). Among 34 patients who were finally diagnosed with an ependymoma, 11 cases had discrepancies, which was the highest mismatch rate among tumor final pathologic types. By frozen biopsy, astrocytoma (n = 5) and ependymoma (n = 5) turned out to be the most discrepant pathologic types and 16 frozen section biopsy cases were "null." Frozen biopsy astrocytoma (n = 5) mostly turned out to be ependymoma in 4 cases., Conclusions: Pathologic findings from frozen biopsy for spinal cord tumors could not be corresponded to final diagnosis, especially when the results of frozen biopsy were ependymoma or astrocytoma. Therefore careful decision making for treatment plans is required., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Introduction: Patients diagnosed with lung cancer may require immediate evaluation of mediastinal lymph nodes to determine treatment plan. Typically, frozen section (FS) analysis has been used, but this analysis can be time-consuming and uses more tissue than touch preparation (TP) cytologic analysis. TP accuracy has been studied in other organs, but no prospective studies comparing TP to FS have been performed on mediastinal lymph nodes in lung cancer. Our goal was to compare the accuracy of TP to FS in these cases., Materials and Methods: After obtaining institutional review board approval, all patients undergoing mediastinal lymph node evaluation for a diagnosis of lung cancer were asked to participate. If consent was given, TP and FS analyses were performed on all mediastinal lymph node stations in all patients and compared to permanent hematoxylin and eosin analysis. Data were collected prospectively., Results: Twenty patients were enrolled. Mean age was 67.7 years. Fifty-five percent (11 of 20) of patients were men. The mean number of lymph node stations sampled in each patient was 3.4. In predicting the stage of the patient, TP had a sensitivity and specificity of 95% and 100%, respectively. FS had a lower sensitivity, 85%, and a specificity of 100%. On permanent analysis, metastatic foci ranged in size from 0.15 mm to 1.5 mm., Conclusions: TP was more sensitive than FS in detecting mediastinal lymph node metastases. The technical difficulty of obtaining full-thickness sections without creating significant artifact may contribute to the lower sensitivity of FS in detecting micrometastases., (Copyright © 2018 American Society of Cytopathology. Published by Elsevier Inc. All rights reserved.)

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.)

Introduction: Inguinal lymph node dissection is an integral part in the management of invasive penile tumors with intraoperative assessment often aiding decision-making during dissection. In this study, we evaluate the diagnostic value of intraoperative frozen section (FS) and analyze clinicopathologic factors that affect its accuracy., Material and Methods: We, retrospectively, reviewed 84 patients with squamous cell carcinoma of the penis who underwent inguinal lymph node dissection at our institution. Intraoperative FS from the superficial inguinal nodes was available in 65 patients and compared with correspondent permanent sections (pathologic node staging [pN]). Sensitivity and specificity were calculated and factors associated with a false negative event were analyzed using logistic regression., Results: The total positive node rate was 60% (39/65). Of 39 pN+ cases, 10 (25.6%) had false-negative FS, whereas the remaining 29 were concordant intraoperatively. Sensitivity and specificity were 0.74 and 1, respectively. On univariable analysis, higher body mass index was associated with a false negative event although there was no association with age, receipt of neoadjuvant therapy, or clinical node stage., Conclusion: Intraoperative FS is highly specific and moderately sensitive for the detection of positive superficial inguinal lymph nodes in penile cancer. Its use can help guide intraoperative surgical planning while limiting its reliance for patients with higher body mass index., (Copyright © 2018. Published by Elsevier Inc.)

Background: Lesions at the skull base warrant careful evaluation of imaging and meticulous preoperative planning. Unnecessary radical resection of these lesions could add to surgical morbidity. Occasionally, dural-based inflammatory or infectious lesions at this site radiologically mimic meningiomas, which are commonly encountered entities at this site. Not all lesions require excision, and it could be harmful in a few cases., Case Description: Two patients had skull base lesions that resembled a meningioma on imaging, whereas frozen section in both cases differed from the preoperative diagnosis, showing an inflammatory lesion in the first case and invasive aspergillosis in the second case. Formalin-fixed, paraffin-embedded sections confirmed the frozen section diagnosis. Safe resection was performed in the first case, whereas surgery was abandoned and the patient was started on antifungal therapy in the second case. Both patients had a good outcome., Conclusions: This report underscores the usefulness of intraoperative frozen section to decide on a further course of treatment when faced with such unexpected situations. Frozen sections and crush smears hold great potential to avoid unwarranted surgical morbidity, particularly for skull base lesions., (Copyright © 2017 Elsevier Inc. 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.)

Introduction: Partial nephrectomy (PN) is the standard therapy for small renal masses. Resection margin assessment continues to be a key issue during PN. Biopsy of the residual kidney and intraoperative gross pathological consultations are the most common methods today. Intraoperative imprint cytology (IC) examinations have been successfully used in other tumor entities to assess surgical margins. We aim to evaluate the diagnostic value of intraoperative IC for surgical margin assessment during PN., Materials and Methods: In addition to routinely performed frozen-section (FS) analysis, intraoperative IC examinations were performed on 114 tumors, which were resected with PN in our department between 2005 and 2010. These 2 were then matched with final histopathological examination findings. Before FS, roll-off IC slides were obtained, air dried, and stained by Hemacolor quick staining. Both the pathologist and the cytologist were blinded to the findings., Results: Our study included 29 women and 76 men. Of 331 IC slides, 317 (96%) contained sufficient diagnostic cells. IC revealed 21 tumors with positive resection margins. Of the 21 positive resection margins, 2 were false positives. IC showed a specificity of 98%, sensitivity of 100%, a positive predictive value of 90%, and negative predictive value of 100%. FS examinations revealed positive resection margins in 20 tumors. One of these 20 margins was false positive. Furthermore FS examination failed to diagnose a positive resection margin in 1 tumor. FS examination showed a specificity of 99% and sensitivity of 98% in assessing surgical margins with a positive predictive value of 95% and negative predictive value 98%., Conclusion: IC examinations exhibit equivalent diagnostic value compared with FS analysis. IC is an inexpensive method with an ability to give rapid and highly accurate information. Like any cytological examination, there is interobserver variability. IC could be considered as an alternative to FS especially when the nature of resection margins is suspected but further investigations are necessary., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Sentinel Lymph Node Biopsy (SLNB) is the standard of care for axillary staging in breast cancer. Multiple Step-section Frozen Section (MSFS) analysis is used in our institution for SLNB. This is performed intra-operatively by freezing sentinel lymph nodes to obtain multiple step-sections which are examined histologically for evidence of metastases. Patients whose sentinel lymph nodes contained macrometastases proceeded to an axillary node clearance during the same operation. 717 patients over a two and a half year period had MSFS analysis. With regards to macrometastases, MSFS analysis had a sensitivity of 93.8%, a specificity of 99.3%, a positive-predictive value of 97.4% and a negative-predictive value of 98.2%. MSFS analysis of sentinel lymph nodes is a safe and accurate procedure. It is a relatively cost-effective alternative to molecular technologies relying on DNA amplification and more accurate than standard frozen section or touch-prep cytology., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Background: Intraoperative frozen section (IFS) examination of sentinel lymph nodes (SLN) is useful in selecting patients with invasive breast cancer for immediate axillary lymph node dissection. However, whether IFS evaluation of the SLNs in ductal carcinoma in situ (DCIS) of the breast has any value has not been previously assessed., Methods: Clinicopathologic data from patients with DCIS who underwent resection with SLN biopsy (2004-2010) were collected to assess the sensitivity, specificity, and accuracy of IFS, and its impact on axillary management., Results: A total of 267 patients with DCIS underwent resection with SLN biopsy and IFS evaluation. Preoperative pathology was DCIS (n = 231), DCIS with microinvasion (n = 24), and DCIS with other lesions (n = 12). Fifty-two (19.5%) patients had invasive breast cancer on final pathology. SLN metastases were identified in 13 (4.8%) patients; however, only 4 (1.5%) were IFS positive. IFS examination was negative in 263 (98.5%) patients. Among patients with SLN metastases, the most common pattern of metastases was either micrometastasis (n = 6) or immunohistochemistry-positive individual tumor cells (n = 4), whereas 3 patients had a macrometastasis. IFS examination was falsely negative in 9 of these 13 patients for a false-negative rate of 69.3%, and a sensitivity and specificity of 31% and 100% respectively. Nine of the 13 patients underwent axillary lymph node dissection and only 1 patient had further axillary metastasis., Conclusions: SLN metastases in DCIS is rare and most commonly involves SLN micrometastasis or immunohistochemistry-positive individual tumor cells. SLN IFS evaluation in DCIS has a low yield and sensitivity, and can be safely omitted to reduce operative duration and cost., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Introduction: Literature controversies exist regarding the prognostic value of VHL mutations. The objective was to compare paraffin-embedded and frozen section specimens for VHL mutations detection and to evaluate the reliability of DNA analysis in formalin-fixed tissues., Methods: Seventy-six patients with clear cell renal cell carcinoma (RCC) previously assessed for VHL status from frozen samples were included. Seventy-three tumor samples were known to be mutated for VHL. DNA was extracted and an electrophoresis was performed to determine DNA quality. The whole coding sequence was synthesized by double PCR amplification followed by sequencing. Sequencing results were compared with those previously determined from frozen samples., Results: DNA could be extracted from the 76 paraffin samples. DNA quality was highly degraded and significantly less amplified by PCR in 34.2%, resulting in no sequence available for analysis in 57.7% and discordance with frozen samples in 42.3% of the cases respectively. VHL mutations were found in 52.1% of the whole paraffin samples whereas 98% were mutated; 72% could be sequenced, resulting in 69.1% of VHL mutations in this subset. Only half of observed mutations were fully consistent with frozen analysis in the 3 exons. Neomutations were found in 10.5% and 28.9% of known mutations in frozen samples were not detected in paraffin blocks. Only DNA quality significantly influenced PCR amplification and sequencing., Conclusion: Tumoral DNA extraction and VHL mutation analysis can be performed from formalin-fixed paraffin-embedded (FFPE) tissue in RCC. But mutations identified tissues are not strictly concordant with those from frozen analysis and therefore results obtained from FFPE samples should be interpreted with care., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Aim: To evaluate the effectiveness of therapeutic mammoplasty with frozen section in achieving negative surgical margins in a single-stage surgery for breast cancer., Methods: Fifty patients affected by early stage breast cancer treated by therapeutic mammaplasties were retrospectively reviewed in this study. Fifty-two therapeutic mammaplasties were accomplished. After resection the specimen was sent to pathologist for examination with frozen section. Tumour positive margins were defined as presence of cancerous cells at ≤ 2 mm from the edge of the specimen. In case of positive margins a second large re-excision was accomplished intra-operatively. All patients were followed every 4 months for the first 2 years and twice a year subsequently., Results: Fifty-two procedures were evaluated (median follow-up of 72.6 months). The overall survival rate was 98% we had a single case of local recurrent disease (1.9%) that progressed to metastatic disease and patient's death. Frozen section as a diagnostic tool for identification of positive margins has been tested. In conclusion we report a sensitivity of 0.83 and a specificity of 0.93; the predictive positive value was 0.62 and the negative predictive value was 0.97, for a final accuracy of 0.94., Conclusion: Frozen section coupled to oncoplastic resections allows a proper control of local disease and can minimize any second surgical look for margins revision., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

The pituitary is responsible for multiple homeostatic functions including metabolism, growth and reproduction. Proteome analysis offers an efficient approach for a comprehensive analysis of pituitary protein expression. The pituitary is usually acquired from postmortem specimens, which may potentially affect the proteome profile by proteolysis. The aim of this study was to determine whether the postmortem pituitary could be used in proteomic analysis combining with Laser capture microdissection (LCM). Digested peptides from LCM captured prolactin (PRL) cells were separated by two dimensional-nanoscale liquid chromatography (2D-nanoLC/MS) and characterized by tandem mass spectrometry (MS). All MS/MS spectrums were searched by SEQUEST and a proteome of 1660 proteins was identified. Category analysis of the proteome revealed an extensive unbiased access to cell component proteins with diverse functional characteristics. The results demonstrated the ability of using 2D-nanoLC/MS to perform sensitive proteomic analysis on limited protein quantities through microdissection. Detailed comparisons between the proteome in question and the one derived from the prolactinoma controls at peptide and protein levels indicated that the two proteomes had similar characters. Overall, our results revealed for the first time the possibility of use of postmortem human pituitary for proteomic research which is important for further studies on disease biomarker identification and molecular mechanisms of prolactinoma tumorigenesis., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Introduction: Intraoperative frozen section diagnosis (FSD) is a very important pathologic examination that can determine the extent of the subsequent surgical procedure. However, FSD is especially difficult in small pulmonary nodules due to severe architectural distortion during cryosection. This study was undertaken to determine the accuracy of FSD of pulmonary nodules and to evaluate the inflation method during cryosection., Methods: We retrospectively reviewed FSD of 229 consecutive pulmonary nodules and evaluated the diagnostic accuracy and efficacy of inflation method during cryosection. Since August 2006, all frozen sections (165, 72.1%) were made after inflation with optimally diluted embedding medium., Results: The FSD were as follows: nonneoplastic lesions (29, 12.7%), benign neoplasms (28, 12.2%), and malignant neoplasms (172, 75.1%). The proportion of the lesions smaller than 2 cm was 60.3% (138 of 229). The frozen section quality of lung tissue was excellent after inflation with diluted embedding medium. Inflated lung specimens harboring minute lesion displayed distinct gross appearance, which could not be palpated. Histologically, open air spaces and normal parenchymal architectures were well preserved. Minute precancerous foci such as atypical adenomatous hyperplasia and bronchioloalveolar carcinoma could be readily identified. After using inflation method during cryosection, both the sensitivity and specificity reached 100%, and the incidence of intraoperative pathology consultation increased markedly, especially small impalpable lesions., Conclusions: The accuracy of FSD and histologic qualities were excellent by using inflation method, especially in cases of impalpable small precancerous lesions. The pathologist could guide with confidence the surgeon in planning the surgical management.

Sentinel lymph node (SLN) biopsy in the head and neck region is attracting attention. If intraoperative frozen section and/or cytology of SLN is available, one can select an appropriate patient who must undergo neck dissection in a one-stage procedure. We began intraoperative diagnosis of SLN biopsy in patients who underwent oral cancer surgery in 2003. From August 2003 to December 2006, 44 previously untreated patients were accumulated. All patients underwent SLN biopsy prior to the resection of primary cancer. Intraoperative diagnosis of SLN biopsy was performed by multislice frozen section analysis. Patients with positive SLN underwent immediate neck dissection in the same session. Imprint cytology specimen was prepared at the same time. The results of frozen section analysis and imprint cytology were compared with postoperative pathologic diagnosis of permanent specimens. The sensitivity, specificity, overall accuracy, positive and negative predictive value of intraoperative multislice frozen section analysis in lymph node basis were 90.9%, 100%, 99.1%, 100% and 99.0%, respectively. On the other hand, the indexes of imprint cytology were 27.3%, 99.0%, 92.0%, 75.0% and 92.6%, respectively. All indexes of intraoperative frozen section analysis were superior to imprint cytology. In our experience, multislice frozen section analysis surpasses imprint cytology in intraoperative diagnosis of SLN biopsy.

Molecular study of gene expression in solid tumors is based largely on mRNA extracted from crushed frozen tumor samples. As most tumors are heterogeneous in composition, molecular alterations acquired by neoplastic cells may be masked by normal epithelial, stromal, and inflammatory cells, which may make up a significant volume of many tumors. We have developed a technique whereby reverse transcription polymerase chain reaction (RT-PCR) can be performed on lesions microdissected directly from frozen tumor sections. This allows for molecular analysis of mRNA from histologically homogeneous cell populations. Cryostat sections are placed onto a thin layer of 2% agarose on a glass slide and stained briefly. Microdissected tissue is immersed in a freezing solution to lyse the cells; aliquots are used directly in RT-PCR reactions without further purification. We successfully amplified cDNA fragments of the beta2-microglobulin, p21Waf1, and BRCA1 genes from small microdissected lesions. Also, we examined the effect of varying thickness of cryostat sections (20 versus 40 microm) and several tissue staining dyes. We estimate that a small microdissected region, containing no more than 200 cells, can provide enough mRNA to make cDNA for 80 to 100 PCR reactions. We believe that this technique will be a useful tool to study gene expression in histologically defined tissues.

Grading of cervical dysplasias at colposcopy by means of rapid frozen section avoids the delay inevitable with paraffin sections. The immediacy of the diagnosis benefits the patient, who can be treated at her first visit. A comparison of grading by frozen sections with paraffin sections has confirmed the safety of the frozen method. Additional advantages are opportunities for optimum orientation and "rescue" of specimens, improved colposcopic training, and the facilitation of special investigations on fresh cervical tissue.

A hybridoma screening format which facilitates the processing of thousands of tissue sections for immunohistochemical analysis is described. The method utilizes sterile replica transfers of monoclonal antibody-containing test supernatants from 96-well culture plates to tissue sections mounted in appropriately sized 8 X 12 arrays, and is extremely rapid and inexpensive.

Biological X-ray microanalysis of diffusible elements within cellular and subcellular compartments requires preparation methods to retain electrolytes in the compartments they occupied in vivo. X-ray microanalysis of frozen-dried, plastic-embedded samples has been used to quantitate electrolytes at the cellular level. We have compared the subcellular elemental distribution in dry cut sections from such samples with that in ultrathin frozen-dried cryosections. Rat pancreases were quench-frozen onto a helium-vapor-cooled copper block. Cryosections were cut at 130-150 K, transferred using a Gatan cold stage, frozen-dried in the column and analysed at 190 K. Tissue fragments were frozen-dried at 190 K, and cut on a dry knife at 293 K. Both samples provided images permitting unambiguous identification of all major compartments except the Golgi complex. Intracellular potassium-to-sodium ratios obtained on frozen-dried plastic-embedded sections were lower than for cryosections (e.g. 1.77 in basal cytoplasm in plastic sections as compared to 4.34 for cryosections) and varied with the pre-embedding procedure (e.g. 1.77 in formaldehyde-fixed as compared to 2.87 in osmium-fixed plastic sections). Potassium gradients between adjacent organelles were large in cryosections and insignificant in plastic-embedded material. Higher cytoplasmic phosphorus, potassium and sulfur concentrations were observed in cryosections. Therefore, a redistribution of electrolytes and covalently bound elements occurred subcellularly in the plastic sections. Calcium was quantifiable in most organelles in cryosections but the plastic lowered sensitivity too much to permit routine calcium quantification. We conclude that in our hands frozen-dried, plastic-embedded samples were compromised and provided lower sensitivity than cryosections.(ABSTRACT TRUNCATED AT 250 WORDS)