To measure the frequency and analyze the rationale and po-tential diagnostic benefits of converting the fine needle aspi-ration (FNA) procedure to core biopsy.
Study Design
The frequency of conversion tocore biopsy was calculated over13 months. Analysis of thesecases was conducted in regardto the appropriateness for con-version and whether the corebiopsy provided additional spe-cific diagnostic information.
Results
During this period, the onsitetriaging pathologist recommended FNA conversion to corebiopsy in 31 of 821 procedures (3.7%). In 3 instances, thecore biopsy could not be performed. The rationale for con-version in the remaining 28 cases (3.4%) included eitherscant aspirated material in 9 cases (32%) or an anticipatedneed for additional histologic material to further character-ize the lesion in the other 19 (68%). In 27 cases (96%), therationale for conversion was considered to be appropriate,and in 3 of these (11%) the core provided a change in diag-nosis. Additional useful diagnostic information was identi-
fied in 12 cases (44%).
Conclusion
Conversion to core biopsy during FNA is infrequent but jus-tified in most cases. Appropriate utilization of this approachis helpful and may be cost effective. (Acta Cytol 2007;
well-established diagnostictool for the rapid diagnosisof tumors and tumor-like
conditions.1 The use of fine-gauge needles in FNABcompared to large-bore cutting needles has furtherhelped to make the process less morbid and more de-sirable to both patients and clinicians.2 In addition,the procedure can be more cost effective, when usedappropriately and judiciously, than needle core biop-sies.3,4
Onsite evaluation and immediate interpretation bya pathologist improves the outcome of the procedureby ensuring the aspiration specimen adequacy, allow-
The superior efficacy of the corebiopsy over aspirated specimens
has been established in certainclinical conditions and lesions at
certain anatomic locations.
Frequency and Rationale of Fine NeedleAspiration Biopsy Conversion to Core Biopsyas a Result of Onsite Evaluation
From the Department of Pathology, Wayne State University School of Medicine and the Barbara Ann Karmanos Cancer Center, Detroit,Michigan, U.S.A.
Drs. Bandyopadhyay and Pansare are Fellows, Department of Pathology.
Drs. Feng and Bhan are Assistant Professors, Department of Pathology.
Drs. Ali-Fehmi and Husain are Associate Professors, Department of Pathology.
Dr. Al-Abbadi is Associate Professor of Pathology and Director of Cytology and Outreach Anatomic Pathology.
Presented at the 95th annual United States and Canadian Academy of Pathology meeting in Atlanta, Georgia, February, 2006.
Address correspondence to: Mousa A. Al-Abbadi, M.D., F.I.A.C., Wayne State University and Detroit Medical Center, Harper UniversityHospital, Department of Pathology, 3990 John R, Detroit, Michigan 48201, U.S.A. ([email protected]).
Financial Disclosure: The authors have no connection to any companies or products mentioned in this article.
ing for possible preliminary diagnosis and triaging ofthe specimen for potential ancillary studies.5,6
The average reported rate of nondiagnostic FNABwithout onsite evaluation as reported by Nasuti et al8is approximately 20%. On the other hand, it has beenfrequently reported in the literature that the sensitivi-ty and specificity of the FNAB procedure is improvedwith immediate adequacy evaluation. The study byNasuti et al8 demonstrated a decrease in the nondiag-nostic rate to 0.1% with onsite evaluation. In addition,other studies have reported a high accuracy rate withan efficiency of 96% when onsite evaluation and in-terpretation was employed during an FNA proce-dure.8,9 Furthermore, the cost savings impact of on-
site evaluation of FNAB specimens on health care ex-penditure is also well established.6,7
Two of the most important contributions of onsiteevaluation are the procurement of adequate materialfor diagnosis and triaging the material for ancillarystudies. This approach is particularly critical in evalu-ating lymphoid neoplasms and other lesions that mayrequire special stains and immunohistochemistry oncell block material. Although the need for the corebiopsy procedure has decreased due to increased sen-sitivity and accuracy of FNAB procedures, fine needleaspirated specimens may not provide adequate diag-nostic material in certain types of lesions.10,11 There-fore, under certain clinical circumstances, onsite con-
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Table I Cases in Which Conversion to Core Biopsy Was Recommended During Onsite Evaluation
Case no. Site FNA interpretation Biopsy diagnosis Reason for conversion to biopsy
1 Neck Acute inflammation Acute and chronic inflammation Characterization, IHC
2 Neck Mixed small cell and Mixed small cell and squamous Characterization
version to core biopsy may be required.In this study, we retrospectively reviewed reports of
all FNA cases and evaluated all cases in which conver-sion to core biopsy was recommended at the time ofonsite evaluation by the cytopathologist. We studiedand analyzed the rationale for conversion to corebiopsy and whether the core biopsy provided addi-tional diagnostic value.
Materials and Methods
After obtaining approval from the internal reviewboard of our institution, retrospective review ofFNAB cases performed from July 2004 to August2005 was conducted. Reports on all cases in whichconversion to core biopsy was deemed necessary at thetime of the onsite evaluation were retrieved, and thepathology reports and glass slides were reviewed. Theavailability of cell block material and the request forflow cytometry in lymphoid aspirations were subse-quently assessed.
In our FNA service, we use 21–23-gauge needles forall of our FNAB procedures. The deep-seated lesions
are aspirated under ultrasound or computed tomo-graphic guidance using 21–23-gauge needles. At least2 passes are performed for each case, with additionalpasses as needed. Two mirror-image smears are usual-ly prepared from each pass, and before discarding theneedle and syringe, the rest of the material is expelledinto an ethanol-based fixative, Cytolyte (Cytyc Corp.,Boxborough, Massachusetts, U.S.A.) for cell blockpreparation or RPMI solution (Invitrogen Corp.,Carlsbad, California, U.S.A.) for potential flow cyto-metric characterization. One smear from each pass isfixed in 95% alcohol for subsequent Papanicolaoustain and the other is air-dried and Diff-Quik–stainedfor immediate evaluation. Ensuing triage decisions arebased only on the evaluation of the Diff-Quik–stainedsmears for each case. The utility of the core biopsy wasassessed on its ability to provide a better sample andincreased cytologic and architectural characterization.
Results
A total of 821 FNA procedures were carried out overthis period in which onsite evaluation by a cytopathol-
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A BFigure 1 Case 3. Neck mass, FNA. (A) FNA showing clusters of spindled cells without significant atypia. The FNA interpretation was a spindle
cell neoplasm (Diff-Quik, × 200). (B) The corresponding core biopsy exhibiting spindle cells in classic palisading pattern with Verocay A and B
ogist was performed. Of these cases, conversion tocore biopsy was recommended in 31 cases (3.7%). In 3of these patients, the core biopsy could not be per-formed due to technical factors and other reasons re-lated to the patient’s clinical condition. In the remain-ing 28 cases, 9 (32%) were considered scant onimmediate adequacy evaluation, prompting a conver-sion to core biopsy. The anticipated requirement foradditional material for ancillary studies resulted incore biopsy conversion in the remaining 19 cases(68%). Table I illustrates the details of these 28 cases.
In 27 cases (96%), the recommendation for core
biopsy was deemed appropriate, based on the immedi-ate onsite interpretation. In 1 case (case 10), adequatematerial was present in the aspirated sample for ancil-lary studies and the core biopsy did not add any addi-tional diagnostic information. The core biopsy pro-vided additional material for immunohistochemistryin 8 cases and special stains for microorganisms in 3cases. In 8 cases, additional morphologic informationwas obtained from the core biopsy, providing a morespecific histologic diagnosis. In 3 patients, the final di-agnosis of the core biopsy interpretation resulted inchange from the initial FNA impression (Table II).
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Table II Change in Diagnosis Resulting from Conversion to Core Biopsy
Site FNA interpretation Biopsy diagnosis Reason for conversion to biopsy
Figures 1–4 demonstrate 4 representative cases inwhich the FNA procedure was converted to core biopsy.
Discussion
As shown in this study, the rate of conversion to corebiopsy based on immediate adequacy of aspirated ma-terial is low (3.7%). Previous studies in the literaturehave investigated the efficacy of FNAB vs. needle corebiopsy in various situations and anatomic locations.However, the design of these studies was slightly dif-ferent from ours. In one study, Yamagami et al12 ana-lyzed the outcomes of FNAB with concurrent needlecore in pulmonary lesions. They concluded that al-though the core biopsy did not add important infor-mation in malignant conditions, it was a superior spec-imen in benign conditions. The same conclusion wasreached by Greif et al13 in their study of lung lesions.In a recent study, Gong et al14 looked at FNA and coreneedle biopsy specimens of intrathoracic lesions andinferred that although both FNA and core needlebiopsy specimens reached similar diagnostic accuracyrates for epithelial malignant tumors, core needle
biopsy specimens proved to be more accurate innonepithelial malignancies and in specific benign le-sions. The premise that needle core biopsy had an in-creased diagnostic accuracy over FNAB of muscu-loskeletal lesions was also confirmed in a study byYang et al,15 particularly in benign soft tissue lesions.That study also emphasized that subclassification andgrading of these tumors was achieved more accuratelyin core biopsy specimens. The usefulness of core spec-imens in soft tissue lesions was also demonstrated in 3cases in our study (cases 3, 4 and 21). In 2 cases (case 3and 4), the FNAB interpretation was rendered as spin-dle cell neoplasm; however, the core biopsies were di-agnostic of a schwannoma and leiomyosarcoma, re-spectively. In the third case (case 21), the aspirate wasscant and the core biopsy provided a diagnosis of atyp-ical myxomatous tumor.
The 2 major reasons for FNA conversion to corebiopsy in our study were scant aspirates in 32% of ourcases and the anticipated need for additional materialin the remaining 68%. Bennert et al16 comparedFNAC and needle core biopsies of soft tissue tumors
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A BFigure 3 Case 24. Neck mass, FNA. (A) FNA material was scant, showing only blood elements (Diff-Quik, × 200). (B) Corresponding core biopsy
of the lymph node with evidence of necrotizing lymphadenitis, also known as Kikuchi’s disease (H-E, × 200).
and found that lesions that yielded a scant specimenon FNA often resulted in an adequate diagnosis oncore biopsy. Moreover, additional specific characteri-zation of the tumor was provided in a small subset oftheir cases by the core biopsy.16
In this study, we found that FNA with onsite evalu-ation was performed on a total of 51 lymph nodes. Flowcytometry was requested in 8 of these cases. Adequateadditional material for flow cytometry was providedby the FNA in all of these cases. This is in agreementwith reports in the literature in which immunopheno-typing of lymphoid lesions by flow cytometry or im-munohistochemical stains on cellular material aspirat-ed by fine needle was achieved in most cases and thediagnostic accuracy was high.17-20
Since the decision for conversion to core was basedon the interpretation of the initial Diff-Quik–stainedsmears, in 32 of our cases further diagnostic materialwas present after the evaluation of additional smearswith Papanicolaou stain and the hematoxylin-eosin(H-E)-stained slides from the cell blocks.
In a multiinstitutional study, Raab et al21 describeddiagnostic errors that may occur in anatomic patholo-gy and found that up to 50% of these are believed tobe due to inadequate sampling of the lesion. In addi-tion and according to a recent study from our institu-tion, diagnostic discrepancies in FNAB from the headand neck region were found to be due to sampling andlack of triage in 67% of cases.22 Conversion to corebiopsy at the time of onsite evaluation may eliminatemany of these discrepant cases and subsequently de-crease error rates.
The superior efficacy of the core biopsy over aspi-rated specimens has been established in certain clini-cal conditions and lesions at certain anatomic loca-tions. Onsite evaluation by the triaging pathologistmay help in recognizing these specific situations andthereby justify conversion to core biopsy from theFNA procedure if required. We think that the onsiteevaluation and immediate triage by a pathologist withrecommendation of conversion of the FNA specimento a core biopsy as needed may save the patient un-
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A BFigure 4 Case 15. Thyroid mass, FNA. (A) FNA revealed scant cellular material that was obscured by blood elements. Rare clusters of possibly
atypical cells were seen (Papanicolaou stain, × 200). (B) The corresponding core biopsy provided evidence of an epithelial metastasis, with the
cells exhibiting clear to granular cytoplasm, consistent with metastatic renal cell carcinoma. The diagnosis was confirmed with
immunohistochemical stains on the core biopsy (H-E, × 200).
necessary additional clinic visits and procedures. Theadoption of this triaging strategy may therefore helpreduce inadequate sampling of lesions and conse-quently reduce the number of false negative diag-noses.
Our experience is that conversion to core biopsy atthe time of onsite evaluation is infrequently requiredbut when used judiciously can be very helpful in de-creasing errors and provide a cost-effective single di-agnostic procedure.
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