Comparison of ethylene glycol, 1,2-propanediol and glycerol for cryopreservation of slow-cooled mouse zygotes, 4-cell embryos and blastocysts

The aim of the study was to analyse the toxicity, the osmolar and cryoprotective activity of ethylene glycol (ETG) in terms of survival rate (SR), cleavage rate (CR) and expanded blastocysts percentage (EBP) of mouse embryos. Early mouse embryos and blastocysts were slowly cooled with ETG, 1,2-propanediol (PROH) or glycerol, and thawed. The Van t'Hoff curve for 1.5 mol/l ETG showed recovery of initial volume within 4 min. No differences were observed in CR and EBP of ETG-exposed compared with non-exposed mouse zygotes. The SR of zygotes frozen with PROH was significantly better than with ETG (92% and 60% respectively; P < 0.01), and a significantly better EBP was achieved for blastocysts frozen with glycerol compared with ETG (75% and 50% respectively; P < 0.05). For 4-cell stage embryos, no differences were observed in SR and EBP between ETG and PROH. Higher EBP was observed for 4-cell stage embryos (53%) frozen with ETG compared with pronucleate stage (19%) and blastocysts (48%). Low toxicity, good SR and EBP were observed for mouse embryos frozen with ETG, the best results being obtained at the 4-cell stage. At other embryonic stages, PROH and glycerol respectively seemed to provide better results.     

What can we learn from the errors in the frozen section diagnosis of pulmonary carcinoid tumors? An evidence-based approach

The intraoperative diagnosis of pulmonary neuroendocrine tumors can be difficult. Frozen section diagnosis was requested on 87 neuroendocrine tumors including 58 typical carcinoids, 8 atypical carcinoids, 18 large cell neuroendocrine carcinomas, and 3 small cell carcinomas from 2405 patients that underwent frozen section diagnosis at Cedars-Sinai Medical Center from 2002 to 2007. The deferral and error rate for carcinoid tumors was 4.13% and 7.5%, respectively, and resulted in 4 unnecessary lobectomies and 2 second thoracotomies. The most common errors included misdiagnoses as lymphoma, squamous carcinoma or metastasis from breast carcinoma. Thirty one pathologic features were evaluated in the 66 carcinoid tumors and 10 frozen sections each of lymphoma, squamous cell carcinoma, and metastatic breast carcinoma. Seven pathologic features were significant by chi square test at P > .05. Positive likelihood ratios identified 11 pathologic features that were useful for the diagnosis of carcinoid tumor from other neoplasms. The applicability of the 11 pathologic features was tested with a group of pathologists, resulting in significant improvement in diagnostic accuracy as measured by pre and posttests. The value of evidence-based pathology and Bayesian statistics to evaluate complex differential diagnoses in pathology is discussed.     

Pitfalls in cytological diagnosis of autoimmune thyroiditis

The aims of this study are to document pitfalls in cytologic diagnosis of autoimmune thyroiditis (AT) and highlight possible ways to minimize them. One hundred consecutive thyroid aspirates with features diagnostic or suggestive of AT, performed and reported by the first author, were included in the study. Follow-up was traced and cytologic features responsible for indecisiveness were re-assessed in those reported as suggestive of AT. The features were then correlated with the results of serologic and thyroid function tests and clinical features, and an attempt was made to amend the final diagnosis using an integrated approach. Seventy eight were diagnostic and 22 were suggestive of AT. In the latter 22, features responsible for the indecisiveness were: cytologic atypia, in the form of nuclear enlargement, irregularity and grooves and altered chromatin texture, in 14 (64%); nucleoli with suspicion of a coexisting neoplasm in three (13.6%), two of which showed epithelial preponderance, crowding and discohesion; sparse inflammation in four (18%); a predominant lymphoid population without epithelial cells resembling a reactive lymph node in one (4.5%); co-existing toxic features in two (9%); and scanty smears in one (4.5%). Eighteen of the 22 suspected of AT had follow-up. Six had been assessed histologically; three with features suspicious of a neoplasm were diagnosed respectively as a papillary carcinoma (PC), Hurthle cell carcinoma (HCC) and a multinodular goitre (MNG) with degenerate changes. The other three were confirmed as AT; one with cytologic atypia, one with sparse inflammation and the third as cytologically resembling a reactive lymphnode. In ten of the remaining 12, the final diagnosis could be revised following an integrated approach with possible reduction of the indecisiveness. Potential pitfalls are: cytologic atypia occurring in AT; abundance or scarcity of background inflammation; low cell yield; and co-existing toxicity and malignancies. Epithelial preponderance over inflammation, nuclear crowding, severe atypia and cell discohesion should raise the possibility of a neoplasm in spite of other features of AT. Awareness of possible pitfalls and adopting an integrated approach, especially in difficult situations, will minimize pitfalls.     

A study of intraoperative rapid frozen section diagnosis focusing on accuracy and quality assessment]

Accuracy of frozen section (FS) diagnoses was investigated in a consecutive series of 1129 intraoperative consultations. In our series, the correct diagnosis including clinically not serious minor errors was made in 96.9% of the cases. Whereas the accuracy ratio of FS diagnosis for unknown pathologic process decreased to 92.2%. Among all the types of tissues, central nervous system was shown to be the most frequently handled for FS, followed by lung/bronchus, breast, liver/biliary tract, lymph node and so forth. The requesting ratio of FS, on the other hand, tended to be high in the following specialties; neurosurgery (46.5%), thoracic surgery (19.0%), general surgery, (10.0%). Deferred diagnosis with a provisional diagnosis and misinterpretations in histology typing without serious clinical problem accounted for 2.7% and 3.1% respectively. Causes of erroneous diagnoses seemed to be multifactorial, such as inappropriate sampling, diagnosis on poor quality histology sections, lack of clinical information, lack of enough experience in FS practice of pathologists, or a combination of more than two of them, though inevitable cases showing minimal cytological and structural atypia were included. Intraoperative consultation by FS diagnosis is now essential to serve a good quality medication to patients. It is thus necessary that to establish a tight peer review system and also to provide an education program with regard to practice in FS diagnosis particularly for young pathologists.     

Accuracy of frozen section diagnosis in soft tissue tumors

This study was undertaken to analyze the accuracy of frozen section (FS) diagnosis of 118 soft tissue tumors with respect to the reasons for which the intraoperative consultation was indicated. Fifty-seven frozen sections were performed for the diagnosis of an unknown pathologic process. Complete agreement was established in 40.3% and the correct pathologic process in 43.9%, the diagnosis was deferred in 14%, and the remaining 1.8% were diagnosed incorrectly. Examination for determination of the adequacy of resection margin (22 cases), lymph node or skip metastases (23 cases), residual or recurrent tumor after previous surgery (29 cases), viable tumor tissue after previous locoregional or systemic therapy (ten cases), and identification of the specimen (five cases) proved to be 95.5%, 95.7%, 96.6%, 90%, and 100% accurate. Considering the whole series, an erroneous answer to a question posed by a surgeon was given in four cases (two false positive and two false negative), of which two cases were a sampling error made by pathologist. Intraoperative consultation by FS in soft tissue tumors is (a) reliable for general rather than exact diagnosis in defining the previously unknown pathologic process and (b) mandatory in evaluating resection margins and any discrepancies between preoperative cytologic and intraoperative gross impression.     

Frozen sections--a retrospective study.

Two hundred and forty-four (244) specimens were examined by frozen section (FS) from 1987 through 1988 at the Kidwal Memorial Institute of Oncology. Of these, eleven (11) were performed for evaluation of the surgical margin of tumours and fifty four (54) for detection of lymph node metastasis. All these examinations (65) proved to be hundred percent (100%) accurate. The remaining 179 frozen sections were performed for the diagnosis of an unknown pathologic process. Of these, 44.69 percent were precisely diagnosed, in 41.9 percent the pathologic process was correctly but not precisely diagnosed, in 11.17 per cent the diagnosis was deferred and remaining 2.24 percent were incorrectly diagnosed with no harmful consequences to the patients. By eliminating the cases where diagnosis was deferred and combining results of "precise diagnosis" with those of "correct pathologic process", the overall accuracy rate was 98.2 percent. Thus, FS has greater benefit when used for the general diagnosis of an unknown pathologic process rather than for an exact or precise diagnosis.     

Fibroadenomas with atypia: causes of under- and overdiagnosis by aspiration biopsy.

Fibroadenoma (FA) is a common benign breast lesion frequently sampled by fine-needle aspiration biopsy (FNAB). Although the cytologic diagnosis is straightforward in most cases, cellular discohesion and atypia in FAs may lead to falsely atypical or positive FNAB diagnoses. Conversely, some adenocarcinomas mimic a fibroadenomatous pattern on FNAB, resulting in a false-negative diagnosis. We reviewed the cytologic and histologic findings in 25 cases with a preoperative FNAB diagnosis of FA, wherein excision was recommended based on atypia. Our aim was to analyze the spectrum of changes causing under- or overdiagnosis in such cases. The smears were assessed for cellularity, cellular discohesion, presence of dissociated intact cells and nucleoli, nuclear pleomorphism, oval bare nuclei, and stromal fragments. The histologic findings were correlated with FNAB features. At excision, 88% of FAs classified as atypical on FNAB were benign (FA with ductal hyperplasia and lactational change, myxoid FA, and other fibroepithelial lesions). Differentiating myxoid FA from colloid carcinoma was difficult due to the abundance of extracellular mucin in which the dissociated epithelial cells were floating. Two (8%) cases were carcinomas on excision; the reasons for underdiagnosis in one case reflected sampling, and in the other, interpretative error. There was one (4%) benign phyllodes tumor which lacked stromal fragments and single stromal cells on FNAB smears. The lesion was called atypical, based on the epithelial discohesion on the smears. We conclude that the majority of FAs with atypia on FNAB are benign lesions. Considering the grave consequences of a false-positive cytologic diagnosis, we recommend a conservative approach in interpreting FNAB smears which overall display a fibroadenomatous pattern.     

经内镜逆行胰胆管造影胰胆管刷检的细胞病理学诊断

目的 探讨经内镜逆行胰胆管造影(ERCP)胰胆管刷检的细胞形态学诊断的敏感性和准确性,及其在诊断胆道和胰腺肿瘤中的作用.方法 回顾性分析长海医院2004年1月至2006年12月行ERCP胰胆管刷片细胞学检查的病例212例,对照术后病理诊断及临床最终诊断,分析胆道及胰腺肿瘤的细胞学特点及意义.结果 212例中样本满意率99%(2例无上皮细胞),细胞学报告阴性者137例,其中临床最终诊断恶性45例(阴性预告值60.2%).细胞学报告低级别异型增生者11例,临床最终诊断恶性6例(阳性预告值54.5%).细胞学报告高级别异型增生和恶性者可信性较高,高级别异型增生23例,1例失随访,临床最终诊断恶性19例(阳性预告值86.4%).细胞学报告恶性41例,临床最终诊断均为恶性(阳性预告值100%).细胞重叠、核大小不等、染色质增粗、黏附性差、坏死背景、核仁、病理性核分裂等特征具有诊断意义.结论 提高诊断效率依赖于从取材、制片、固定到阅片诊断各个环节的质量控制;区分"低级别异型增生"和"高级别异型增生",对临床实际工作的指导意义更大.     

Follicular lesion of undetermined significance in thyroid FNA revisited

Controversy exists regarding the validity of follicular lesion of undetermined significance (FLUS), an indeterminate diagnostic category of The Bethesda System for Reporting Thyroid Cytopathology (BSRTC). According to BSRTC, FLUS carries a 5–15% risk of cancer. This study was designed to determine if cytomorphology could stratify FLUS into subgroups with different risks of malignancy. Reports of 127 consecutive FNAs reported as FLUS with subsequent tissue diagnoses were evaluated for the presence of various cytologic features and the results were correlated with histological diagnoses. FLUS cases with focal nuclear atypia (nuclear overlap/crowding, nuclear grooves/membrane irregularities, nuclear enlargement, and/or nuclear pseudoinclusions) were more frequently malignant on excision whereas those with architectural atypia (microfollicles) were more often benign on excision (P < 0.05). The presence of any one or more of these nuclear features increased the risk of carcinoma in subsequent thyroid resection. Papillary carcinomas predominated in excised FLUS cases with focal nuclear atypia whereas most FLUS with architectural atypia were adenomas or hyperplastic nodules on histological evaluation. BSRTC recommends that thyroid aspirates containing follicular cell nuclear and/or architectural atypia insufficient for a diagnosis of suspicious for follicular neoplasm, suspicious for malignancy or malignant be classified as FLUS. Our findings indicate that FLUS cases with focal nuclear atypia carry a risk for malignancy that is substantially higher than that assigned to FLUS and are best classified as suspicious. FLUS cases lacking these atypical nuclear features have a risk for malignancy that approximates the risk BSRTC has assigned to FLUS. Diagn. Cytopathol. 2014;42:18–22. © 2013 Wiley Periodicals, Inc.     

Clinical and pathologic features of ductal carcinoma in situ associated with the presence of flat epithelial atypia: an analysis of 543 patients.

Flat epithelial atypia is an alteration of mammary terminal duct lobular units that is considered to be a precursor to, or early stage in, the development of some forms of ductal carcinoma in situ. No prior study has systematically evaluated the relationship between various clinico-pathologic features of ductal carcinoma in situ and the presence of coexistent flat epithelial atypia. An understanding of such relationships could provide insight into the connection between flat epithelial atypia and ductal carcinoma in situ. We reviewed slides from 543 ductal carcinoma in situ patients enrolled in a case-control study assessing epidemiologic and pathologic risk factors for local recurrence. We examined the association between the presence of flat epithelial atypia and various clinical factors, pathologic features of the ductal carcinoma in situ, and the presence of coexistent atypical ductal hyperplasia, lobular neoplasia, and non-atypical columnar cell lesions. In univariate analysis, the presence of flat epithelial atypia was significantly related to ductal carcinoma in situ nuclear grade (most common in low grade, least common in high grade; P<0.0001), architectural pattern (most common in micropapillary and cribriform, least common in comedo; P<0.0001), absence of comedo necrosis (P<0.001), absence of stromal desmoplasia (P=0.02) and absence of stromal inflammation (P=0.03). In multivariable analysis, features of ductal carcinoma in situ independently associated with flat epithelial atypia were micropapillary and cribriform patterns and absence of comedo necrosis. Additionally, flat epithelial atypia was significantly associated with the presence of atypical ductal hyperplasia, lobular neoplasia, and columnar cell lesions in both univariate and multivariable analyses. These observations provide support for a precursor-product relationship between flat epithelial atypia and ductal carcinoma in situ lesions that exhibit particular features such as micropapillary and cribriform patterns and absence of comedo necrosis.     

A novel immunohistochemical staining method allows ultrarapid detection of lymph node micrometastases while conserving antibody

We developed a novel ultrarapid immunohistochemical staining method in which an AC electric field is used to facilitate detection of tumor cells. Frozen sections of non-small cell lung cancer in lymph nodes were fixed in acetone for 2 min, after which they were incubated for 2 min with an anti-pancytokeratin antibody cocktail and then with EnVision(TM) complex under an alternating current (AC) electric field. The sections were then incubated with a chromogen (3,3'diaminobenzidine) for 3 min and counterstained with hematoxylin. This method enabled detection of tumor cells in frozen sections in less than 15 min. In addition, we were able to reduce the amount of antibody used by more than 90% when the sections were incubated under the AC electric field for a longer period. This method could be a useful tool for frozen section diagnosis and research. Furthermore, with this method the cost of immunohistochemical staining can be reduced.     

Early colorectal carcinomas: CD10 expression, mucin phenotype and submucosal invasion

We analyzed 170 tumors (polypoid, 98; non-polypoid, 72) of early colorectal carcinoma with or without submucosal invasions (Tis and T1 of TNM classification) from 161 patients to evaluate correlations between clinicopathological factors and immunohistochemical expressions of CD10, MUC2, and MUC5AC. The coexistence of adenomatous components was significantly less common in non-polypoid carcinomas (4.2%) than in polypoid carcinomas (66.3%) (P < 0.0001). Non-polypoid carcinomas were smaller in size and tended to infiltrate into the submucosa with higher incidence of lymphatic and venous permeations. CD10 was more frequently expressed in non-polypoid carcinomas (70.8%) than in polypoid carcinomas (51.0%) (P= 0.01). Total carcinomas with high grade atypia showed higher incidence of CD10 expression (60.6%) than those with low grade atypia (28.9%) (P < 0.0001). Carcinomas with low grade atypia exhibited a higher incidence of MUC2 and MUC5AC expression (91.1% and 57.8%, respectively), when compared with carcinomas with high grade atypia (41.6% and 20.0%, respectively) (both, P < 0.0001). In submucosal invasive carcinomas with residual intramucosal carcinoma component (IMCC), CD10 expression in IMCC and submucosal invasive carcinoma component (SMCC) simultaneously exhibited identical positive or negative results, regardless of the polypoid or non-polypoid growth pattern. The CD10 expression may occur in the early stage of carcinogenesis within the mucosa, and these neoplasms may retain CD10 in SMCC, possibly resulting in more advanced stages of stromal invasion and distant metastases. In conclusion, our data suggest that the CD10 expression and mucin phenotypes may be potentially useful markers for estimating biological properties of early colorectal carcinomas.     

Immunohistochemical assessment of Ki67 and p53 expression assists the diagnosis and grading of ulcerative colitis-related dysplasia

AIMS: To assess whether Ki67 and p53 immunostaining may assist the diagnosis and grading of ulcerative colitis-related dysplasia. METHODS AND RESULTS : Location of Ki67 staining and location and intensity of p53 staining were assessed in ulcerative colitis (UC) cases showing the features of high-grade dysplasia (HGD, n = 14), low-grade dysplasia (LGD, n = 22), 'indefinite for dysplasia' (n = 12), or regenerative atypia (RA, n = 22). Good intra- and inter-observer reproducibilities were demonstrated in the performance of these assessments. All the dysplasia cases showed extension of Ki67 staining above the basal third of the crypt. Moderate intensity p53 staining was seen in 10/22 RA cases, but strong intensity p53 staining was seen only in cases of dysplasia. All the cases of HGD showed extension of Ki67 and p53 staining above the basal two thirds of the crypt. CONCLUSIONS: Restriction of Ki67 staining to the basal third of the crypt appears to exclude a diagnosis of dysplasia whereas strong intensity p53 staining suggests a diagnosis of dysplasia. Restriction of Ki67 or p53 staining to the basal two-thirds of the crypt appears to exclude a diagnosis of HGD.     

Intranuclear cytoplasmic inclusion is a significant diagnostic feature for the differentiation of lobular endocervical glandular hyperplasia from minimal deviation adenocarcinoma of the cervix

Lobular endocervical glandular hyperplasia (LEGH) is a cervical lesion with pyloric gland metaplasia. Minimal deviation adenocarcinoma (MDA) is an extremely well differentiated form of endocervical adenocarcinoma (AC). To date, it is difficult to differentiate LEGH from MDA because they share similar clinical, radiological, and immunohistochemical features. Furthermore, the cytological features of LEGH and MDA have not been well defined. In the present study, we describe the cytological features of LEGH and MDA. We reviewed 24 cases of LEGH (18 pure and six mixed forms) and four MDA cases of the cervix. A total of 40 cytologic smears from 28 patients were reviewed. Abundant yellow mucin was frequently present in both LEGH and MDA; however, an INCI was found in 22 of the 24 LEGH cases and it was not found in either MDA or adenocarcinoma cells associated with LEGH. Neither cell atypia nor architectural distortion was observed in LEGH. In MDA, slight cellular atypia, three dimensional, irregular cell clustering, and prominent nucleoli were observed. The presence of an INCI is a good parameter for the diagnosis of LEGH. Cytology is an effective aid in the differentiation of LEGH from MDA.     

Fine-needle aspiration cytology of benign and malignant adenomyoepithelioma: report of two cases.

Cytological features of a malignant spindle-cell variant and a benign tubular variant of adenomyoepithelioma were examined to improve diagnosis of this tumor. Fine-needle aspiration cytology, of both a malignant and a benign case, characterized cellular and cohesive cell clusters composed of epithelial and myoepithelial cells. The smears of the malignant case were rich in spindle-shaped myoepithelial cells, admixed with a few epithelial cells. In about a fourth of the clusters, atypical cells with enlarged hyperchromatic nuclei and prominent nucleoli comprised more than 20% of cells. The smears of the benign case were composed of tubular epithelial cells surrounding one to several layers of myoepithelial cells with clear cytoplasm. Mild atypia was occasionally noticed. A review of the literature showed that a cytological diagnosis of malignancy is not warranted, if nuclear atypia is not generally severe. Focal severe atypia is not definitively indicative of benignity or malignancy.     

外阴鲍文祥丘疹病的诊断与误诊分析

目的：探讨鲍文祥丘疹病的临床与病理特征以及误诊原因。方法：回顾分析22例鲍文祥兵疹病的论断、治疗情况，并进行鉴别诊断。结果：22例分别误诊为鲍文病、尖锐湿疣、黑色素痣或恶性质黑色素瘤等，通过病理协助诊断，全部确诊为鲍文样丘疹病。经治疗后好转，随访2年未见复发。结论：鲍文样丘疹病易与鲍文病疾病相混淆，诊断要结合临床形态观察和病理组织学检查，才能准确诊断和治疗鲍文样丘诊病，该病有自愈倾向。     

Papillary renal cell carcinoma. Report of two cases.

Papillary renal cell carcinoma is an uncommon variant of renal cell carcinoma which has unique features including hypovascularity or avascularity, extensive stromal macrophage infiltration and better prognosis than that for nonpapillary renal cell carcinoma. Two cases of papillary renal cell carcinoma presenting hypovascular or avascular angiology are presented. Histologically, the two tumors had a purely papillary structure. Papillae were lined by a layer of epithelial cells which lacked prominent cellular atypia, and there were numerous macrophages in the stroma. In addition, in one patient, extensive calcification of the tumor capsule was present. Furthermore, our experience in the present study with imprint cytology indicates that it offers corroborative information for the intraoperative diagnosis made on the basis of frozen section examination.     

Cytologic features of pancreatic intraepithelial neoplasia and pancreatitis: Potential pitfalls in the diagnosis of pancreatic ductal carcinoma

Fine‐needle aspiration (FNA) has played a significant role in the diagnosis of pancreatic masses but false‐positive diagnoses occur. The Anatomic Pathology files were searched for FNAs of pancreas with subsequent resections. FNAs with a diagnosis of positive for or suspicious for adenocarcinoma followed by a benign resection specimen were reviewed and the surgical pathology and cytology findings correlated. Six cases had a cytologic diagnosis of adenocarcinoma or suspicious for adenocarcinoma but resection specimens were benign. In two cases, a non‐invasive intraductal papillary mucinous neoplasm (IPMN) without significant dysplasia was present surrounded by foci of pancreatic intraepithelial neoplasia (PanIN). In both cases, the degree of atypia within the IPMN was less than that seen cytologically. The nuclear features of the PanIN overlapped those seen in the smears. In two cases, a neuroendocrine neoplasm was present accompanied by multifocal PanIN. The cytologic features of the neuroendocrine neoplasm did not correlate with the material cytologically diagnosed as adenocarcinoma. The cytologically atypical epithelium was similar to the PanIN. Two diagnoses of adenocarcinoma were made cytologically but the pancreatectomy specimens revealed pancreatitis with reactive atypia. Cytologic diagnosis of pancreatic adenocarcinoma has high specificity. Six cytologic misdiagnoses of adenocarcinoma occurred in 105 patients. The cytologic features of these misdiagnoses correlated with histopathologic changes of intermediate to high‐grade PanIN or marked reactive atypia in severe pancreatitis. PanIN may be an under recognized, but significant source of false‐positive results. Diagn. Cytopathol. 2011. © 2010 Wiley‐Liss, Inc.     

Accuracy of and reasons for frozen sections: a correlative, retrospective study

Previous studies on the accuracy of frozen sections (FS) were not based on the reasons for which the FS was performed. By omitting this important information, those studies reported FS accuracy of 94% to 97.4%. The current study analyzes the accuracy of FS diagnoses based on the reasons for which they were conducted. Of 482 specimens examined by FS in 1986, 41 were performed for evaluation of section margins of tumors, 29 for identification of unknown tissue, and 43 for detection of lymph node metastases. All 113 of these examinations proved to be 100% accurate. The remaining 369 FS were performed for diagnosis of an unknown pathologic process. Of these, 83.47% were precisely diagnosed; in 10.30%, the pathologic process was correctly, but not precisely, diagnosed; in 3.79%, the diagnosis was deferred; and the remaining 2.44% were incorrectly diagnosed (with no harmful consequences to the patients). By eliminating the cases of deferred diagnoses, the accuracy rate increased to 86.76%. Therefore, we suggest that the pathologist and the surgeon should not draw any conclusion from an inconclusive interpretation of FS and should proceed as though an FS had not been performed. When combining results of "precise diagnoses" with those of "correct pathologic process," the overall accuracy rate increased to 97%. The investigators conclude that FS should be used for a general diagnosis of a pathologic process rather than for an exact or precise diagnosis. Finally, we suggest that a similar survey of FS be periodically performed in every pathology department as part of its quality assurance program.