Advances in Anatomic Pathology:
Recent Trends in Quality, Patient Safety, and Error Reduction in Nongyn Cytology
Silverman, Jan F. MD
Department of Pathology and Laboratory Medicine, Drexel University College of Medicine, Allegheny General Hospital, Pittsburgh, PA
All figures can be viewed online in color at http://www.anatomicpathology.com.
Reprints: Jan F. Silverman, MD, Department of Pathology and Lab Medicine, Allegheny General Hospital, 320 E. North Avenue, Pittsburgh, PA 15212 (e-mail: email@example.com).
This article reviews recent trends in nongyn cytology with an emphasis on error reduction, second opinion, and critical diagnosis. Compared with the surgical pathology literature, there is only a limited number of reports addressing these topics in nongyn cytology. Discussion of the error literature in nongyn cytology is presented with the intent to better identify error-prone cytology cases that could prompt intradepartmental consultation or an outside cytology expert's second opinion. The cytology second-opinion literature is also reviewed with the recommendation that interinstitutional second opinions add value to patient care. Last, the recent concept of critical value (critical diagnosis) in cytopathology is presented. All these initiatives promote patient safety, improve quality, decrease errors, and benefit patients.
Since the Institute of Medicine's (IOM) landmark publication “To Error Is Human,” there has been a reemphasis on quality, improved patient safety, and error reduction in anatomic pathology.1 In gyn cytology, there are a number of well- established quality assurance (QA) and quality control (QC) monitors to evaluate the performance of the cytology laboratory and individual cytotechnologists and pathologists. This article will address a number of recent trends in nongyn cytology, focusing on improved quality, patient safety, and error reduction, including a discussion of the nongyn cytology error literature, the value of second opinions in nongyn cytology and the concept of critical values (critical diagnoses).
ERRORS IN NONGYN CYTOLOGY
Clinically significant diagnostic error rates in surgical pathology have been reported in the range from 0.26% to 1.2%,2 but there is very limited nongyn cytology literature documenting the error rate. To further complicate the analysis, there is a variety of different ways to define errors, including diagnostic versus operational errors, clinically significant versus academic errors, errors discovered by perspective versus retrospective review, errors identified by expert's second opinion, intradepartmental or interinstitutional reviews, and errors identified by reviewing malpractice claim, which is equivalent to errors defined by society and the judicial system.2
The Institute of Medicine's definition of an error is a failure of a planned action to be completed as intended, otherwise, known as an execution error, or use of a wrong plan to achieve an aim, which is considered a planning error.1 Troxell reported patterns and trends in anatomic pathology by reviewing malpractice claims for 2 time periods (1995 to 1997 and 1998 to 2003) from the database of the Doctors' Company, a physician-owned professional laboratory insurance company.3 In the initial time period (1995 to 1997), miscellaneous fine needle aspirations (FNAs) accounted for 16 of 218 claims (7% of total claims), owing to a false negative rate of cancer of 19% and a false positive rate of 58%. FNA of the breast represented 12 of 218 claims (6% of total claims), owing to 58% false negative rate of cancer, and 33% false positive rate. In the second time period from 1998 to 2003, miscellaneous FNAs and breast FNAs, decreased to 3.5% and 2% of the total claims, respectively. In contrast, Pap smear claims represented 17 and 11% of the total claims, respectively, in the 2 time periods. One can speculate that with more recent opportunities for education through cytopathology fellowships and workshops presented at regional and national meetings, the increased level of expertise in FNA cytology has accounted for the decreased FNA claims.
In a separate article, Troxell elaborates on the breast FNA errors from 1995 to 1997, which represented 6% of the claims.4 A majority of the claims were false negatives, owing to reporting a benign diagnosis of fibrocystic change or negative in a sparsely cellular nondiagnostic specimen, with no recommendation to repeat the FNA or do tissue biopsy in a case that ultimately proved to be malignant. False positive diagnoses were usually owing to interpretative errors, especially misclassifying fibroadenomas as carcinoma.4 Troxell recommends that a statement be part of every FNA breast report noting the value of the triple test, that is, correlation of the FNA with mammographic and ultrasound and clinical examination. Troxell also recommends that every breast FNA report include a statement reminding the clinician that the procedure has a false negative rate of 3% to 5% and a false positive rate of 0.5% to 2%, the consequences of which can be decreased by using the triple test strategy. He also suggests that when possible, the pathologist should review the mammogram/ultrasound report and discuss the clinical findings with the clinician before issuing the FNA report, if the pathologist has not carried out the procedure. If the pathologist knows that there is triple test discordance, this should be noted in the report that further studies such as additional biopsies are recommended.
The question of what constitutes an adequate specimen in breast FNA is controversial.5 Some researchers propose that if the pathologist does the aspirate and believes that the lesion has been adequately sampled, then an acellular or scantily cellular smears can be consistent with a diagnosis of fibrocystic change, if the cytologic findings correlate with the clinical and mammographic findings. However, if the pathologist is not the aspirator and has not reviewed the mammographic findings, then an FNA specimen that is acellular or scantily cellular, should not be interpreted as negative or consistent with fibrocystic change, but rather signed out as nondiagnostic owing to sparse cellularity, which would prompt the clinician to do additional sampling.4
Another way to identify pathology “errors” is auditing amended reports. In a College of American Pathologists' (CAP) Q-Probe Study, Nakhleh and Zarbo reported the amended rate in surgical pathology.6 However, the cytology literature is limited, with only a few reports discussing reviewing amended reports as a quality assurance exercise.7 I believe that auditing amended reports is helpful in identifying error-prone cases and/or cytopathologists having difficulties with certain types of specimens.
The CAP has a number of studies and surveys, which provides practicing pathologists the opportunity to assess problem-prone cases and specimens that can potentially be a diagnostic challenge in nongyn cytology, including subclassification of breast carcinoma by FNA cytology,8 FNA of adenocarcinoma/ metastatic carcinomas that resemble hepatocellular carcinoma,9 FNA of hepatocellular carcinomas that can be mistaken for adenocarcinomas,10 separating carcinoid tumor from mediastinal thymoma,11 carcinoid tumor from small cell carcinoma of the lung,12 pitfalls in the salivary gland FNA cytology,13 distinguishing small cell carcinoma from nonsmall cell carcinoma,14 the potential for pulmonary hamartoma to be a source for a false positive diagnosis,15 misinterpreting normal cellular elements in FNA cytology for a neoplasm16 and pitfalls in the diagnosis of papillary carcinoma of the thyroid.17 The CAP Interlaboratory Comparison Program also evaluated the problematic areas in effusion cytology18 and cerebral spinal fluid cytology.19 In addition, there have been a number of articles discussing potential nongyn cytology pitfalls such as false positive interpretation in respiratory cytology.20,21
It has also been noted that standardization in the diagnostic terminology and morphologic criteria can help decrease variation that can lead to errors. The National Cancer Institute (NCI) has sponsored conferences resulting in the Bethesda Systems for reporting cervical cytology, thyroid, and breast with the goal of standardizing diagnostic categories and criteria, terminology, and standards for adequacy.22–24
All of the above studies and pathology departments monitoring its quality indicators in nongyn cytology such as amended report rate and nongyn cytology/surgical pathology correlation can help cytopathologists to identify problem-prone cases and individual pathologist's performance. However, depending on each pathology department's expertise, the types of cases that are prone to error may vary. When encountering such cases, it would be helpful to obtain intradepartmental consultation and/or an outside expert's second opinion.
A 32-year-old woman presented with a 7-cm thyroid nodule underwent FNA biopsy. Cytologic findings both in the smears and cell block showed 3-dimensional papillary clusters with fibrovascular cores best appreciated in the cell block (Figs. 1A, B). The FNA diagnosis was papillary thyroid carcinoma with a recommendation for tissue confirmation. The resected specimen showed a follicular adenoma with pseudopapillary hyperplasia. In retrospect, although there was a papillary architectural arrangement of the cells, the follicular cells lacked the essential diagnostic nuclear changes to make a diagnosis of papillary carcinoma. However, the resected specimen did contain a micropapillary carcinoma, which was not the lesion aspirated.
In Case 2, an 82-year-old man underwent an FNA biopsy for a lung nodule that showed a hypercellular specimen consisting of fairly uniform atypical cells arranged in 3-dimensional groups, loose clusters, and individually scattered cells. Some of the cells had plasmacytoid features. The preliminary diagnosis was possible neuroendocrine neoplasm, but immunohistochemical studies were negative for synaptophysin and chromogranin (Figs. 2A, B). The pathologist was then informed by the clinician that this male patient had a history of breast carcinoma. Additional immunohistochemical studies were carried out on the cell block, which showed positive staining of the neoplastic cells for estrogen receptor protein and gross cystic disease fluid protein (GCDFP) with negative staining for TTF-1, confirming a metastatic breast carcinoma (Figs. 2C–F).
Although there is a well-established literature in surgical pathology,25–30 there have been only a limited number of reports discussing the value of second opinion in cytopathology.31–34 A number of institutions require routine interinstitutional anatomic pathology consultation as a quality and patient safety initiative with the intent of reducing errors. Abt et al,27 reported all interinstitutional anatomic pathology consultation diagnoses made during a 1-year period in which the consultation diagnosis was compared with the original diagnosis. Of the 777 cases reviewed, 71 (9.1%) were evaluated to be discrepant diagnoses, resulting in a change in patient evaluation or treatment in 45 (5.8%) of the patients. Cytology specimens, including cervical and vaginal smears and fluids, accounted for 8 of 37 of the discrepant diagnosis (11%) and FNAs for 8 of 38 (11%) discrepant diagnoses. These 16 patients accounted for 21% of the discrepancies in the 75 patients, with only a cytologic specimen or FNA biopsy diagnosis, compared with 51 (7.8%) discrepant diagnosis among the remaining 667 patients with only a surgical pathology diagnosis, which was statistically significant.27
Layfield et al,31 reported the combined results of the University of Utah's School of Medicine and Duke University Medical Center, in which 146 cases underwent second-opinion review during a 2-year period. There were 24 disagreements of which 11 were major. A 16% disagreement rate reported in their series was similar to the disagreement rate reported in surgical pathology, but 8% were major disagreements that were slightly higher than surgical pathology results. At Duke University, the disagreements occurred more frequently in thyroid and liver FNAs, and cervical Pap smears.
Lueck et al,33 report their experience with a mandatory second-opinion review policy at the University of Iowa for 499 second-opinion cytology cases in which the authors evaluated whether the disagreement was minor or major. A major disagreement was defined as a 2-step difference resulting in a potential change in treatment or prognosis. There were 37 (7.4%) major disagreements and 55 (11%) minor disagreements. Six cases, which included 3 thyroid FNAs, 1 parotid FNA, and 2 nongyn cytologies accounted for 1.2% of the cases that had a change in clinical management. The authors commented that major cytology disagreements identified by second opinion are common, but cases resulting in a change in clinical management are few, similar to findings published in the surgical pathology second-opinion literature. Bomeisl et al,34 reported their experience with second opinion at Ohio State University Medical Center, in which a mandatory second-opinion policy does not exist, but the practice is well established. The authors evaluated 742 FNA cytology cases submitted from outside laboratories, in which there was a minor disagreement in 132 cases (17.8%) and major disagreement in 69 cases (9.3%), determined by the consulting pathologist. Follow-up data were available on 60 of 69 of the major discrepancy cases and based upon this information, the second-opinion diagnosis was supported in nearly 2 out of 3 of the cases, and the initial outside diagnosis was supported in the remaining 1out of 3 of the cases. However, the authors commented that in 55% of the cases in which the original institution diagnosis was better supported, either the entire case slides were not submitted, or slides contained material that was considered nondiagnostic. The second-opinion diagnosis prompted a change in clinical management in 32 of 742 cases (4.3% of cases), with FNAs most likely resulting in change of management or therapy in cases from the thyroid (13 cases); neck (soft tissue and lymph node, 9 cases); salivary gland (2 cases); and liver (2 cases). The authors also commented that the diagnosis by board-certified cytopathologists rendering the second opinion were better supported by follow-up, in contrast to nonboard-certified cytopathologists' review (75 vs. 38%). I concur with the above studies recommending the need of interinstitutional second opinions, when a patient is referred from an outside hospital to the treating institution.
A 72-year-old man had an FNA biopsy of a left lung base lesion at an outside hospital, which was followed by a left lower lobe segmental resection at the treating hospital. The initial FNA biopsy was reported as adenocarcinoma (Figs. 3A–C). Microscopic examination of the resected specimen at the treating hospital showed organizing pneumonia with reactive bronchioalveolar cell proliferation (Figs. 4A–C). In retrospect, the atypical cells represented reparative proliferation of the bronchoalveolar cells that was misinterpreted as adenocarcinoma in the outside FNA evaluation. This case illustrates the value of obtaining a second opinion at the treating hospital before definitive treatment.
CRITICAL VALUES IN CYTOLOGY
The concept of critical values is well established in clinical pathology.35–40 Recently, we introduced the concept of critical values in surgical pathology,41,42 which was followed-up by the Association of Directors of Anatomic and Surgical Pathology (ADASP) conducting a multiinstitutional survey of their members concerning the concept of critical values in surgical pathology and cytology.43 The majority of the respondents supported the concept of critical values in surgical pathology and cytopathology. Also in follow-up to our surgical pathology critical value article, we did a similar analysis addressing the concept of critical values in cytology based upon a review of 2000 cytology reports from Allegheny General Hospital (AGH) and the Mayo Clinic (Rochester, MN).44 This review included 200 gynecologic, 400 nongynecologic, and 500 FNA cytology reports from each institution to determine the prevalence of cytology critical values.44 The types of critical value cases included unexpected malignancy, discrepancy between preliminary and final FNA diagnoses, and organisms in nongyn, gynecologic, and FNA specimens. There was a total of 52 critical-value cases (2.6%), which included 1 (0.3%) gynecologic, 15 (1.9%) nongynecologic, and 36 (4.5%) FNA cases. Therefore, nongynecologic cases made up a significant majority of all our critical value cytology cases. We also surveyed pathologists and clinicians concerning the concept of cytology critical value.44 The participants included 13 pathologists and 13 clinicians at Allegheny General Hospital and Mayo Clinic, and 9 nationally recognized senior cytopathologists. The survey listed 18 potential critical value cases, which required grading the urgency of a phone call from 1=no phone call necessary, 2=phone call within 24 hours, 3=phone call as soon as possible. The participants could also list additional cytology diagnoses they believed constituted a critical value case. Most of the respondents agreed that a new diagnosis of malignancy (especially an unexpected malignancy or one involving a critical site) required a telephone call, and that there was a need for an immediate phone call when microorganisms in immunosuppressed patients were identified, or if there was a significant disagreement between the preliminary and the final FNA diagnosis. However, there were differences of opinion concerning a number of potential critical value cases, although in general, good agreement was found among pathologists and clinicians concerning, which diagnoses would require notification of a physician and the degree of urgency. After the publication of the surgical pathology and cytology articles, and the ADASP survey,44 an ad hoc committee of ADASP was formed to propose guidelines for what constituted critical value cases.45 These guidelines fell into 3 categories including: (1) cases that have immediate clinical consequences, (2) unexpected or discrepant findings and (3) infections. Clearly, cytology cases can fall under all these categories, such as an FNA of a malignancy causing a superior vena cava syndrome or a neoplasm causing paralysis, discrepant preliminary versus final FNA diagnosis and bacteria, mycobacterium, viruses, or fungi in cerebro spinal fluid (CSF) cytology specimens from immunocompromised or immunocompetent patients. Nongyn cytology examples include organisms such as pneumocystis carinii, fungi, or viruses in a bronchoalveolar lavage (BAL) or bronchial washings or bronchial brushing cytology specimens from immunocompromised or immunocompetent patients (Fig. 5). The CAP (policy ANP.12175) now requires that hospitals have a policy regarding the timely communication and documentation of significant or unexpected surgical pathology findings. The lack of such a policy is a phase-I deficiency. I believe that the guidelines should also include significant or unexpected cytology findings.
In conclusion, in addition to the traditional cytology QA and QC monitors such as cytohistologic correlation, retrospective reviews, monitoring 2 step discrepancies between cytotechnologists and pathologists, complete versus partial Pap smear rescreening, etc., there are other initiatives that can improve quality and patient safety and reduce errors in nongyn cytopathology. Recognition of the types of cases that are prone to errors is important, and the value of intradepartmental and interinstitutional consultation. In addition, the appreciation that critical value cases occur in cytology requires rapid notification. All of these initiatives promote patient safety, improve quality, decrease error, and benefit patients.
1. Kohn LT, Corrigan JM, Donaldson MS. To err is Human. Building a Safer Health System. Committee on Quality of Health Care in America. Institute of Medicine 2000 Washington DC National Academy Press
2. Troxel DB. Medicolegal aspects of error in pathology. Arch Pathol Lab Med. 2006;130:617–619
3. Troxel DB. Error in surgical pathology. Am J Surg Pathol. 2004;28:1092–1095
4. Troxel DB. Diagnostic pitfalls in surgical pathology: uncovered by a review of malpractice claims, part II: breast fine needle aspirations. Int J Surg Pathol. 2000;8:229–231
5. Stanley MW, Abele J, Kline T, et al. What constitutes adequate sampling of breast lesions that appear benign by clinical and mammographic criteria. Diagn Cytopathol. 1995;13:473–485
6. Nakhleh RE, Zarbo RJ. Amended reports in surgical pathology and implications for diagnostic error detection and avoidance. A College of American Pathologists Q-probes study of 1 667 547 accessioned cases in 359 laboratories. Arch Pathol Lab Med. 1998;122:303–309
7. Stastny JF, Geisinger KR, Michael CW, et al. Another quality assurance issue—amended reports: what do we really know about them?. Diagn Cytopathol. 1998;18:67–70
8. Young NA, Mody DR, Davey DD. Diagnosis and subclassification of breast carcinoma by fine-needle aspiration biopsy. Results of the interlaboratory comparison program in non-gynecologic cytopathology. Arch Pathol Lab Med. 2002;126:1453–1457
9. Renshaw AA, Haja J, Wilbur DC, et al. Fine-needle aspirates of adenocarcinoma/metastatic carcinoma that resemble hepatocellular carcinoma. Correlating cytologic features and performance in the College of American Pathologists non-gynecologic cytology program. Arch Pathol Lab Med. 2005;129:1217–1221
10. Renshaw AA, Haja J, Wilbur DC, et al. Fine-needle aspirates of adenocarcinoma/metastatic carcinoma that resemble hepatocellular carcinoma. Correlating cytologic features and performance in the College of American Pathologists non-gynecologic cytology program. Arch Pathol Lab Med. 2006;130:19–22
11. Renshaw AA, Haja JC, Neal MH, et al. Distinguishing carcinoid tumor of the mediastinum from thymoma. Correlating cytologic features and performance in the College of American Pathologists interlaboratory comparison program in non-gynecologic cytopathology. Arch Pathol Lab Med. 2006;130:1612–1615
12. Renshaw AA, Haja J, Lozano RL, et al. Distinguishing carcinoid tumor from small cell carcinoma of the lung. Correlating cytologic features and performance in the College of American Pathologists non-gynecologic cytology program. Arch Pathol Lab Med. 2005;129:614–618
13. Hughes JH, Volk EE, Wilbur DC. Pitfalls in salivary gland fine-needle aspiration cytology. Lessons from the College of American Pathologists Interlaboratory Comparison program in nongynecologic cytology. Arch Pathol Lab Med. 2005;129:26–31
14. Renshaw AA, Voytek TM, Haja J, et al. Distinguishing small cell carcinoma from non-small cell carcinoma of the lung. Correlating cytologic features and performance in the College of American Pathologists non-gynecologic cytology program. Arch Pathol Lab Med. 2005;129:619–623
15. Hughes JH, Young NA, Wilbur DC, et al. Fine-needle aspiration of pulmonary hamartoma. A common source of false-positive diagnoses in the College of American Pathologists interlaboratory comparison program in nongynecologic cytology. Arch Pathol Lab Med. 2005;129:19–22
16. Young NA, Mody DR, Davey DD. Misinterpretation of normal cellular elements in fine-needle aspiration biopsy specimens. Observations from the College of American Pathologists interlaboratory comparison program in non-gynecologic cytopathology. Arch Pathol Lab Med. 2002;126:670–675
17. Renshaw AA, Wang E, Haja J, et al. Fine-needle aspiration of papillary thyroid carcinoma. Distinguishing between cases that performed well and those that f poorly in the College of American Pathologists non-gynecologic cytology program. Arch Pathol Lab Med. 2006;130:452–455
18. Moriarty AT, Stastny J, Volk EE, et al. Fluids—good and bad actors. Observations from the College of American Pathologists interlaboratory comparison program in non-gynecologic cytology. Arch Pathol Lab Med. 2004;128:513–518
19. Renshaw AA, Hughes JH, Wang E, et al. Leukemia/lymphoma in cerebrospinal fluid. Distinguishing between cases that performed well and poorly in the College of American Pathologists interlaboratory comparison program in non-gynecologic cytology. Arch Pathol Lab Med. 2006;130:1762–1765
20. Policarpio-Nicolas MLC, Wick MR. False-positive interpretations in respiratory cytopathology: exemplary cases and literature review. Diagn Cytopathol. 2007;36:13–19
21. Silverman JF. Inflammatory and neoplastic processes of the lung: differential diagnosis and pitfalls in FNA biopsies. Diagn Cytopathol. 1995;13:448–462
22. Solomon D, Nayar R. The Bethesda System for Reporting Cervical Cytology. Definitions, Criteria and Explanatory Notes 20042nd ed New York Springer
23. Ali SZ, Cibas ES. The Bethesda System for Reporting Thyroid Cytopathology. Definitions, Criteria and Explanatory Notes 2010 New York Springer
24. Simsir AA. Breast fine needle aspiration biopsy: prevailing recommendations and contemporary practices. Clin Lab Med. 2005;25:631–654
25. Kronz JD, Westra WH, Epstein JI. Mandatory second opinion surgical pathology at a large referral hospital. Cancer. 1999;86:2426–2435
26. Tsung JSH. Institutional pathology consultation. Am J Surg Pathol. 2004;28:399–402
27. Abt AB, Abt LG, Olt GJ. The effect of interinstitutional anatomic pathology consultation on patient care. Arch Pathol Lab Med. 1995;199:514–517
28. Tomaszewski JE, Bear HD, Connally JA, et al. Consensus conference on second opinions in diagnostic anatomic pathology. Who, what, and when. Am J Clin Pathol. 2000;114:329–335
29. Silverberg SG, Corson JM, Dehner LP, et al. Association of Directors of Anatomic and Surgical Pathology. Consultations in surgical pathology. Am J Surg Pathol. 1993;17:743–745
30. Silverberg SG. The institutional pathology consultation. Documentation of its importance in patient management. Arch Pathol Lab Med. 1995;119:514–517
31. Layfield LJ, Jones C, Rowe L, et al. Institutional review of outside cytology materials: a retrospective analysis of two institutions' experiences. Diagn Cytopathol. 2002;26:45–48
32. Selman AE, Ninemann TH, Fowler JM, et al. Quality assurance of second opinion pathology in gynecologic oncology. Obstet Gynecol. 1999;94:302–306
33. Lueck N, Jensen C, Cohen MB, et al. Mandatory second opinion in cytopathology. Cancer Cytopathol. 2009;117:82–91
34. Bomeisl PE, Alam S, Wakely PE. Interinstitutional consultation in fine-needle aspiration cytopathology. Cancer Cytopathol. 2009;117:237–246
35. Lundberg GD. When to panic over an abnormal value. MLO Med Lab Obs. 1972;4:47–54
36. Emancipator K. Critical values: ASCP practice parameter. Am J Clin Pathol. 1997;108:247–253
37. Clinical Laboratory Improvement Amendments of 1988: Final rule (42 CFR Part 405, et al), 57 Federal Register 1992;7001-7186.
38. Code of Federal Regulations. Title 42 CFR Parts 493 to end 1998 Washington, DC US Government Printing Office (revised annually).
39. Rabinovitch A. The College of American Pathologists (CAP) Laboratory Accreditation Checklists 2000 Northfield, ILL College of American Pathologists
41. Pereira TC, Liu Y, Silverman JF. Critical values in surgical pathology. Am J Clin Pathol. 2004;122:201–205
42. Silverman JF, Pereira TC. Critical values in anatomic pathology. Arch Pathol Lab Med. 2006;130:638–640
43. Pereira TC, Silverman JF, LiVolsi V, et al. A multi-institutional survey of critical diagnoses (critical values) in surgical pathology and cytology. Am J Clin Pathol. 2008;130:731–735
44. Pereira TC, Clayton AC, Tazelaar HD, et al. Critical values in cytology. Diagn Cytopathol. 2006;34:447–451
45. Silverman JF, LiVolsi V, Fletcher CDM, et al. Association of Directors of Anatomic and Surgical Pathology. Critical diagnoses (critical values) in anatomic pathology. Am J Surg Pathol. 2006;30:897–899
nongyn cytology; error; critical diagnosis; second opinion
© 2010 Lippincott Williams & Wilkins, Inc.
Highlight selected keywords in the article text.