Fine needle aspiration cytology of thyroid gland diseases

From 1982 to 1987, 2,433 lesions of the thyroid gland in 1,796 patients were examined by fine needle aspiration (FNA). Cytopathology classified 66.91% of the aspirates as benign, 10.76% as thyroiditis, 4.89% as suspected (unspecified) neoplasia, 1.31% as positive for malignancy and 16.11% (392) as unsatisfactory. The histologic diagnoses in 257 cases were compared with cytologic diagnoses to determine the accuracy of FNA cytology of thyroid lesions, yielding a sensitivity of 71.43%, a specificity of 100% and an accuracy of 95.09%. This data strongly supports thyroid FNA as an important preoperative diagnostic tool. Follicular carcinomas were difficult to cytologically differentiate from nonmalignant follicular neoplasms, and papillary thyroid carcinomas less than 2 cm in diameter in elderly patients were frequently misdiagnosed or diagnosed only as "suspect lesion."     

Diagnostic value of fine needle aspirates processed by ThinPrep® for the assessment of axillary lymph node status in patients with invasive carcinoma of the breast

X. Jing, E. Wey and C. W. Michael Diagnostic value of fine needle aspirates processed by ThinPrep® for the assessment of axillary lymph node status in patients with invasive carcinoma of the breast Objective: To evaluate the utility of ThinPrep® as an optional specimen processing method for the detection of axillary lymph node metastasis of invasive breast carcinoma. Methods: A computer SNOMED search from the file at our institution between January 2003 and August 2011 retrieved a total of 209 fine needle aspiration (FNA) specimens of axillary lymph nodes prepared by ThinPrep and followed by axillary lymph node biopsy and/or dissection. Original cytological diagnoses and corresponding histological diagnoses were documented. Using the histological diagnoses as the gold standard, the diagnostic parameters including sensitivity, specificity, positive (PPV) and negative predictive values (NPV) and diagnostic accuracy were calculated. Both cytology and histology slides from cyto‐histologically discrepant cases were reviewed. Results: Out of a total of 209 specimens, 193 (92%) had adequate diagnostic material while the remaining 16 specimens (8%) were inadequate for cytological assessment. The diagnostic specimens included 168 invasive ductal carcinomas (IDC), 15 invasive lobular carcinomas (ILC) and 10 mixed carcinomas (IDC and ILC). Excluding 19 cases with malignant cells on FNA in which no residual tumour was found in fibrotic lymph nodes after neoadjuvant therapy (cytology and histology confirmed on review) ThinPrep detected nodal metastasis with an overall sensitivity of 77.5%, specificity of 100%, PPV of 100% and NPV of 53.7%. Diagnostic accuracy was 82.2%. There was no difference in Bloom–Richardson grade or the number or size of metastases between tumours with true‐positive and false‐negative cytology. Sampling error was the sole factor contributing to cyto‐histological discrepancy. Conclusions: ThinPrep is a good alternative to the conventional smear for cytological assessment of axillary lymph node status in patients with invasive breast carcinoma, particularly when specimens are collected at remote sites or when cytologists are not available for assistance during FNA.     

Fine needle aspiration of metastatic and hematologic malignancies clinically mimicking pancreatic carcinoma.

The fine needle aspiration (FNA) cytology findings in 19 cases of hematopoietic and metastatic neoplasms that radiographically mimicked primary pancreatic carcinoma are reported. These cases represented 11% of 176 malignant diagnoses in a series of 304 pancreatic FNAs. The cytologic diagnoses included 7 non-Hodgkin's lymphomas, 2 Hodgkin's lymphomas, 6 small cell carcinomas (4 lung, 1 gallbladder, 1 skin), 3 squamous cell carcinomas (2 cervix, 1 esophagus) and 1 hepatocellular carcinoma. In six cases the pancreatic lesion was the initial presentation of malignant disease. These included five lymphomas, which probably involved peripancreatic lymph nodes, and a metastatic small cell carcinoma of pulmonary origin. Recognition of unusual morphologic features of pancreatic carcinoma raised the possibility of extrapancreatic malignancies. Electron microscopy and immunocytochemistry performed on FNA specimens were helpful in selected cases. The FNA diagnosis of hematopoietic and metastatic neoplasms that clinically mimic pancreatic carcinoma prompts appropriate clinical studies and treatment and eliminates the need for open pancreatic biopsy and/or resection.     

Interobserver variability in the fine needle aspiration biopsy diagnosis of follicular lesions of the thyroid gland

OBJECTIVE: To study the degree of interobserver variability in the interpretation of fine needle aspiration (FNA) biopsies of the thyroid, specifically in the categorization of follicular lesions (FLs), and to examine the accuracy of FNA diagnosis of FLs with surgical follow-up. STUDY DESIGN: Fifty cases were chosen with surgical follow-up and a cytologic diagnosis of either FL (21) or follicular neoplasms (29). Representative slides were selected for each case and circulated to 4 pathologists for review. Interobserver variability was assessed using pairwise K statistics. Accuracy of the cytologic diagnoses in predicting a nonneoplastic or neoplastic outcome was determined by measuring sensitivity and specificity. Likelihood ratios and receiver operator characteristic curves were calculated for each reviewer. RESULTS: Interobserver agreement between the 4 pathologists was fair to substantial (K scores, 0.199-0.617). The accuracy of the 4 pathologists' cytologic diagnoses in predicting the surgical outcome was 77-90% for follicular neoplasms and 53-74% for nonneoplastic diagnoses. CONCLUSION: FLs present diagnostic difficulties as to cytologic categorization. A wide range of interobserver agreement was found in this study of 4 pathologists from the same institution. Some pathologists make greater use of intermediate categories, such as FL, favor nonneoplastic, or FL, favor neoplastic, whereas others show more definitive categorization into benign and neoplastic groups.     

Clinicopathologic analysis of fine needle aspiration cytology of the thyroid. A review of 1,613 cases and correlation with histopathologic diagnoses

OBJECTIVE: To evaluate the accuracy of fine needle aspiration (FNA) of thyroid lesions at our institution and to ascertain its usefulness in determining the therapeutic approach. STUDY DESIGN: The authors reviewed the results of 1,613 cases of FNA cytology of thyroid nodules performed from 1999 to 2001 at the Department of Pathology, Chonnam National University Hospital. Cytologic diagnoses were compared with histologic diagnoses in 207 cases that included both FNA and thyroid surgery. RESULTS: The sensitivity for the detection of neoplasms (carcinoma and follicular adenoma) was 78.4% and the specificity 98.2%. A false positive diagnosis was made in 1 case (1.8%) and false negative ones in 28 cases (21.5%). The diagnostic accuracy was 84.4%, with a positive predictive value of 99.0% and negative predictive value of 66.3%. The predictive value of a cytologic diagnosis was 100% in papillary carcinoma. CONCLUSION: FNA is a useful test in determining the therapeutic approach of thyroid lesions.     

Diagnostic utility of galectin-3 in aspirates of thyroid follicular lesions

OBJECTIVE: To investigate the expression of galectin-3 in various thyroid follicular lesions, including diffuse hyperplasia, nodular hyperplasia, and benign and malignant follicular neoplasms, to clarify the diagnostic utility of galectin-3 in aspirates of follicular lesions. STUDY DESIGN: A total of 146 follicular lesions diagnosed cytologically, obtained from patients who had undergone thyroidectomy for either benign or malignant nodules, were evaluated using Papanicolaou-stained slides and cell blocks with galectin-3 immunostaining. We primarily categorized the aspirated specimens as benign, indeterminate or suspicious for a follicular neoplasm based on cellularity, architectural arrangement of the follicular cells and presence or absence of colloid. Galectin-3 immunostaining was evaluated according to the proportion and intensity of positively stained cells. Cytologic diagnoses were correlated with the results of galectin-3 and categorized into 3 groups (benign, indeterminate for malignancy, suspicious for malignancy) and compared with the corresponding histologic diagnoses. RESULTS: When the histologic diagnoses were compared with the cytologic diagnoses, the accuracy in the distinction between benign and malignant cases was 79.5% except for 8 cytologically and 3 histologically indeterminate cases. Except for 11 indeterminate cases, there were 18 (12.3%) discrepant cases. False positive cases included 8 of 62 (12.9%) nodular hyperplasias and 1 of 42 (2.4%) follicular adenomas. Of 9 false negative cases, 4 minimally invasive carcinomas and 2 widely invasive carcinomas were included. Three follicular tumors of uncertain malignant potential were cytologically categorized as malignant, and all cases showed positivity for galectin-3. CONCLUSION: Galectin-3 could be used as a useful supplementary marker for cytologic diagnosis, although it was not an absolute marker in determining whether a lesion was benign or malignant.     

Fine needle aspiration biopsy diagnosis of mucoepidermoid carcinoma. Statistical analysis

Fine needle aspiration (FNA) biopsy is an increasingly popular method for the evaluation of salivary gland tumors. Of the common salivary gland tumors, mucoepidermoid carcinoma is probably the most difficult to diagnose accurately by this means. A series of 96 FNA biopsy specimens of salivary gland masses, including 34 mucoepidermoid carcinomas, 51 other benign and malignant neoplasms, 7 nonneoplastic lesions and 4 normal salivary glands, were analyzed in order to identify the most useful criteria for diagnosing mucoepidermoid carcinoma. Thirteen cytologic criteria were evaluated in the FNA specimens, and a stepwise logistic regression analysis was performed. The three cytologic features selected as most predictive of mucoepidermoid carcinoma were intermediate cells, squamous cells and overlapping epithelial groups. Using these three features together, the sensitivity and specificity of accurately diagnosing mucoepidermoid carcinoma were 97% and 100%, respectively.     

Papillary carcinoma of the thyroid gland. Analysis of 94 cases with preoperative fine needle aspiration cytologic examination

From 1979 to 1983, 94 papillary carcinomas of the thyroid gland were examined histologically in our institute after a preoperative cytologic examination. Material for cytologic examination was obtained using fine needle aspiration (FNA) biopsy. Eighty-five (90.4%) of the 94 examined cytologic smears were representative. Among these 85 cases suspicion for malignancy or malignancy itself was found in 64 cases (75.3%). The remaining 21 smears, classified as cytologically not as suspect for malignancy, were reclassified and the previous diagnosis had to be revised in one case. In the other 20 cases no clue for malignancy could be demonstrated even after reexamination. In the 85 cases with representative cytologic findings, tumor size was determined on surgical material, in order to establish how many carcinomas with a diameter less than 3 cm could not be reached by FNA biopsy. Except for one case, all carcinomas with negative preoperative cytologic findings had a diameter less than or equal to 3 cm. The question arising is the possibility of improving the accuracy of FNA biopsy in tumor detection within cold nodules of the thyroid by combined use of scintigraphy and ultrasound-guided FNA biopsy.     

Comparative findings of lymphocytic thyroiditis and thyroid lymphoma

OBJECTIVE: To compare the cytologic features of histologically proven lymphocytic (Hashimoto's) thyroiditis (Hashimoto's thyroitidis) and primary thyroid lymphomas (TL). STUDY DESIGN: Clinical histories, smears (stained with Diff-Quik, Papanicolaou stain or hematoxylin and eosin [HE]) and surgical specimens (HE slides) were reviewed in 25 cases of lymphocytic thyroiditis and 12 of thyroid lymphomas. RESULTS: Surgical specimens of thyroiditis were obtained for other medical reasons: goiter and compressive symptomatology in 21 cases and neoplasms in 4 (2 papillary carcinomas, 1 follicular carcinoma and 1 oncocytic adenoma). Seven cases were primary lymphomas, and 5 were secondary. Histologically there were 6 large B-cell lymphomas, 2 mantle cell lymphomas, 1 Burkitt lymphoma, 2 mucosal-associated lymphoid tissue lymphomas in blastic transformation and 1 of unknown type. Sensitivity for the diagnosis was 67.5% for HT and 92.3% for lymphoma. CONCLUSION: A heterogeneous population of small and large lymphocytes was the most frequent pattern in both diseases. The presence of a monotonous population of large lymphocytes or, more rarely, of small cells indicates a probable TL. Plasma cells favor HT. Other techniques are mandatory for the differentiation of cases with inconclusive diagnoses.     

Atypical epithelial cells, cannot exclude papillary carcinoma, in fine needle aspiration of the thyroid

OBJECTIVE: Atypical epithelial cells, cannot exclude papillary thyroid carcinoma (AEC-PTC), in fine needle aspiration (FNA) of the thyroid is a controversial diagnostic category that might cause a dilemma in patient management. STUDY DESIGN: Eighty-eight thyroid FNA specimens from 86 patients with a diagnosis of AEC-PTC were retrieved from our files in a 10-year period from December 1996 to December 2006. Of the 86 patients, 57 had follow-up histologic diagnoses and were included in this study. The cytologic and histologic materials were reviewed and correlated. RESULTS: Of the 57 patients, all had cytologic atypical features suggestive of PTC. Twenty-five cases of PTC were identified at surgery (44%). Review of the cytologic materials identified the following cytologic features, either alone or in combination strongly associated with PTC at resection: rare intranuclear cytoplasmic invagination (INCI), squamoid cytoplasm and psammoma bodies. CONCLUSION: The most common reasons for rendering the diagnosis of AEC-PTC in FNA of thyroid include rare atypical cells in a cystic thyroid nodule or a background of Hashimoto's thyroiditis. The cytologic features of LNCI, squamoid cytoplasm and psammoma bodies should alert the pathologist. Focal cytologic features of PTC in FNA samples are strongly associated with papillary carcinoma on resection.     

Diagnostic efficacy of immunocytochemistry on fine needle aspiration biopsies processed by thin-layer cytology

OBJECTIVE: To evaluate the efficacy of immunocytochemistry (ICC) performed on smears processed by thin-layer cytology (TLC). STUDY DESIGN: During the period January 2001-September 2003, 3,573 consecutive fine needle aspiration biopsies were processed with both conventional smears (CSs) and TLC diagnosed by a single pathologist; 113 required immunocytochemical study. CSs were fixed in ethanol whereas TLC slides were processed with the ThinPrep 2000 method (Cytyc Co., Marlborough, Massachusetts, U.S.A); both were stained with Papanicolaou stain. ICC staining was carried out on only TLC slides. RESULTS: The 113 cytologic cases were grouped as follows: 32 thyroid nodules with 16 histologic controls (HCs), 24 lymph nodes (regardless of location) with 15 HCs, 18 liver and pancreatic lesions (3 HCs), 11 lung nodules (6 HCs), 5 kidney and adrenal gland lesions (1 HC), 6 abdominal (2 HCs) and 4 mediastinal masses (1 HC), 6 salivary gland tumors (3 HCs), 4 bone masses (2 HCs) and 3 subcutaneous lesions (1 HC). ICC contributed to the diagnosis in 104 cases (92%), whereas it was inconclusive in 9. The cytologic diagnoses were histologically confirmed in 46 of 50 cases (92%). CONCLUSION: ICC can be successfully applied on TLC slides with better results than on CSs, and its yield can be useful in making the correct diagnosis on fine needle aspiration biopsy.     

Solitary nodular goiter. Review of cytomorphologic features in 441 cases.

OBJECTIVE: To study the cytomorphologic features of solitary nodular goiters (SNG). STUDY DESIGN: May-Grünwald-Giemsa-stained smears in 441 SNG diagnosed by ultrasonography and fine needle aspiration (FNA) and found to have optimum cellular material at review were subjected to detailed cytologic assessment. The age of the patients ranged from 11 to 75 years, with a median of 35. Male: female ratio was 69:372. The parameters for cytologic assessment included cellularity, colloid content, acinar formation, papillary formation, intranuclear cytoplasmic inclusions, nuclear grooves, marginal vacuoles, Hürthle cells and various inflammatory cells. Histopathology reports on thyroidectomy specimens were available in 27 cases from two Delhi hospitals. RESULTS: Hyperplastic nodules (68 cases) differed significantly from colloid goiters (269 cases) by having more cases with excessive cellularity, acinar formation and marginal vacuoles (P < .001). There was also a significant difference with respect to papillary formation and moderate-to-excessive colloid content (P < .001). As compared to hyperplastic nodules, neoplasms (60 cases) had a significantly higher number of cases with papillary formation, intranuclear inclusions and nuclear grooves but lower number of cases with marginal vacuoles (P < .01-.001). Among neoplasms, usual papillary carcinoma (19 cases) differed from follicular neoplasms (20 cases) with respect to acinar formation, papillary formation and nuclear grooves (P < .001). A significant difference was also observed with respect to colloid content and nuclear inclusions. Follicular variant of papillary carcinomas (FVPC) (10 cases) emerged as a distinct cytologic entity following review and differed from usual papillary carcinomas in having a higher number of cases with acinar formation, tubular formation and marginal vacuoles (P < .01-.001) and lower number of cases with nuclear grooves (P = .05). FVPC also differed from follicular neoplasms with respect to papillary formation, tubular formation, intranuclear inclusions and nuclear grooves (P < .01-.001). Overall cytohistologic agreement was achieved in 24 of 27 (88.9%) cases. CONCLUSION: Detailed cytologic assessment of FNA smears-in SNG was helpful in highlighting parameters that differentiate between various types of goiters.     

Fine needle aspiration cytologic findings in the black thyroid syndrome

The cytologic presentation of a case of minocycline-associated black thyroid adenoma in a 30-year-old woman is described. A nodule was discovered in the left lobe of the patient's thyroid gland, and fine needle aspiration (FNA) was performed; the nodule and adjacent thyroid were subsequently surgically removed. The cytologic findings included sparse groups of epithelial cells with prominent intracytoplasmic pigment granules. The surgical specimen was interpreted as black thyroid adenoma. This case is unusual in that the pigment had accumulated preferentially in the adenoma. In retrospect, the finding of distinctive pigment in the aspirate of the nodule suggests that the black thyroid syndrome should be considered whenever dark-brown pigment is encountered in FNA cytologic specimens from the thyroid gland.     

Fine needle aspiration biopsy of Hashimoto's thyroiditis. Sources of diagnostic error.

OBJECTIVE: To determine the accuracy of cytologic interpretation in the diagnosis of Hashimoto's thyroiditis (HT). STUDY DESIGN: At Ottawa Hospital from 1987 to 1994, 1,638 fine needle aspiration biopsies (FNABs) from thyroid were performed. HT was suggested in 184 FNAB samples taken from 157 patients. Of the 184 aspirates diagnosed with HT, 39 had corresponding surgical specimens taken from 31 patients. A retrospective review of these FNABs and surgical pathology slides formed the basis of this study. RESULTS: In 27 (69%) aspirates, HT was diagnosed on both the FNAB and surgical specimens. In 10 of 27 FNABs an associated lesion was not sampled by FNAB. In four of these 10 aspirates some of the cellular features of HT were misinterpreted, and the possibility of an associated neoplasm could not be ruled out. This resulted in four false positive diagnoses. In 12 (31%) FNABs from nine patients, the cytologic diagnosis of HT was not confirmed histologically. These cases included five Hürthle cell adenomas and one case each of follicular adenoma, nodular goiter, macrofollicular adenoma and malignant lymphoma. This resulted in five false negative diagnoses. CONCLUSION: These results support the value of FNAB in the diagnosis of HT. The presence of hyperplastic follicular cells on FNAB samples from HT may mimic a follicular neoplasm and result in a false positive interpretation. Adequate sampling of the thyroid is important, particularly when there is an associated lesion. The diagnosis of lymphocytic thyroiditis should not be made when only a few lymphocytes are present. Finally, pleomorphic Hürthle cells may be present in aspirates from Hürthle cell neoplasms and underdiagnosed as HT, especially when they are associated with a few lymphocytes.     

Fine needle aspiration biopsy versus sputum and bronchial material in the diagnosis of lung cancer. A comparative study of 168 patients

A group of 168 consecutive lung cancer patients in whom a definitive diagnosis of primary lung cancer was established either in a conventional cytologic specimen of sputum or bronchial material or in a specimen obtained by fine needle aspiration (FNA) biopsy was reviewed to compare the relative accuracies between the modalities of sputum and bronchial material on one hand versus FNA cytology on the other in the diagnosis of lung cancer. The patients included in the study were selected from a total of 1,093 patients who had been diagnosed and treated for lung cancer at Duke University Medical Center over the five-year period of January 1, 1980, through December 31, 1984. In 325 (29.8%) of the 1,093 patients, a definitive cancer diagnosis was established from histopathologic study alone, without any cytologic diagnoses. In 420 patients (38.4%), both histologic and cytologic material had been interpreted as being conclusively diagnostic for lung cancer. In 348 patients (31.8%), a cytologic diagnosis of lung cancer was made without a histologic confirmation. Thus, in a total of 768 (70.3%) of the 1,093 cases, a definitive cytologic diagnosis of cancer had been made. Of these 768 patients, 168 had been evaluated by both conventional respiratory cytologic methods (examination of sputum and bronchial material) and with FNA biopsy cytology. In 9 patients (5.4%), only conventional respiratory cytologic specimens were conclusively diagnostic for cancer. In 122 patients (72.6%), only the FNA biopsy specimen was diagnostic. In 37 patients (22.0%), both conventional respiratory specimens and FNA specimens yielded a definitive lung cancer diagnosis. The FNA specimen was the only positive cytologic specimen in 90.2% of large cell undifferentiated carcinomas, 79.5% of adenocarcinomas, 66.7% of small cell undifferentiated carcinomas and 58.2% of squamous cell carcinomas. In 26.5% of the patients, a diagnosis of cancer could have been established on conventional cytologic specimens, without the necessity of proceeding to percutaneous FNA biopsy. From this study, it is concluded that the techniques of conventional respiratory cytology and FNA biopsy cytology are complementary in the diagnosis of lung cancer. While the percentage of lung cancers diagnosed by FNA biopsy cytology alone is much greater than that obtained by conventional respiratory cytology alone, more than one-fourth of these cancers could be detected by the less invasive techniques of sputum collection and bronchoscopy.     

Fine needle aspiration cytology of neoplasms metastatic to the breast

The fine needle aspiration (FNA) cytologic findings in 18 cases of metastatic neoplasms of the breast are reported. The cases were encountered in a combined series of 2,529 FNA breast biopsies, of which 666 were malignant; the metastatic neoplasms of the breast thus constituted 2.7% of all the malignant breast tumors. The series consists of 15 women and 3 men, with a mean age of 48 years (range of 11 to 73 years). Sixteen biopsies confirmed metastatic malignancy in patients with known extramammary primaries; the prebiopsy clinical diagnoses in six of the patients were benign breast lesions. In eight patients, the clinical differential diagnosis was either a benign or malignant primary breast lesion versus a metastatic malignancy. In two additional patients, the FNA biopsy identified metastatic neoplasms from unsuspected extramammary primaries. The metastatic neoplasms included three small-cell carcinomas of the lung, one squamous-cell carcinoma of the lung, two malignant melanomas, three ovarian malignancies, including a dysgerminoma, and one each of carcinoma of the fallopian tube, endometrial carcinoma, transitional-cell carcinoma of the urinary bladder, prostatic carcinoma, acute granulocytic leukemia, lymphoma, mycosis fungoides, hepatoma and neuroblastoma of the retroperitoneum. Recognition of unusual cytologic patterns raised the suspicion of, or confirmed the diagnosis of, malignancy in all cases, with no false-negative diagnoses. None of the cases were cytologically interpreted as a primary breast malignancy. Ancillary studies performed on the FNA material, including immunocytochemistry, contributed to a definitive diagnosis in three cases. FNA diagnosis of metastatic malignancy of the breast is essential in order to avoid unnecessary mastectomy and to ensure appropriate chemotherapy and/or irradiation treatment.     

Fine needle aspiration cytology of atypical carcinoid of the lung

The cytologic features of eight atypical carcinoid tumors of the lung, as observed in fine needle aspiration (FNA) specimens, are described in detail. They were compared with 21 pulmonary squamous-cell carcinomas, 16 adenocarcinomas, 5 small-cell undifferentiated carcinomas, 3 large-cell undifferentiated carcinomas and 1 typical carcinoid tumor. Atypical carcinoid tumor was easily distinguished from the other pulmonary neoplasms in most instances. Only two poorly differentiated squamous-cell carcinomas (one of which had atypical carcinoid as a component) and one small-cell undifferentiated carcinoma had similar cytologic features. One atypical carcinoid also had cytologic features similar to small-cell undifferentiated carcinoma. Because atypical carcinoid and small-cell undifferentiated carcinoma, at times, may be difficult to separate in FNA specimens, surgical resection of all stage I neoplasms with cytologic features evocative of either neoplasm is recommended.     

A new look at cervical cytology. ThinPrep multicenter trial results.

The objective of this study was to compare the sensitivity of a new test method with the smear method for detection of neoplasia of the uterine cervix. The new procedure, the ThinPrep process, is an automated, fluid-based technique for the collection and preparation of exfoliated and aspirated cytologic specimens. A single sample from each patient was split and prepared both with the smear and test methods. The diagnostic results from the two slides were compared in this blind study. Among a total of 2,655 patients, diagnoses concurred in 92% of cases and were within one diagnostic level of each other 98% of the time. The ThinPrep method facilitated the detection of more low-grade lesions (P less than .001, McNemar's test). In addition, the test method decreased the number of ambiguous interpretations. The ThinPrep method appears to improve the cervical cytologic smear quality by the harvest of a random and reproducible sample, with a reduction in artifacts. The new method improves the sensitivity of the cervical cytologic screening test.     

Thyroid Cytology and Risk of Thyroid Cancer: Differences Among Indeterminate Specimens

ObjectiveTo assess the potential for stratification of indeterminate cytologic findings on fine-needle aspiration (FNA) of thyroid nodules in an effort to improve therapeutic strategies.MethodsWe attempted to determine the malignant risk associated with various indeterminate FNA cytologic patterns by correlation of specimens with the final histologic diagnosis. For this analysis, we identified 294 computerized medical records of surgically treated thyroid nodules during a 5-year period at our institution with the corresponding FNA cytology reports available.ResultsOf the 294 surgical cases, 162 with a positive or indeterminate cytologic report were selected, reviewed, and classified. Of 52 patients with positive cytologic findings on FNA, 51 (98%) had a final histologic report of a malignant thyroid nodule. Of 110 patients with indeterminate specimens, 30 (27%) had a final histologic diagnosis of thyroid carcinoma. The presence of nuclear atypia was predictive of thyroid carcinoma in 75% of patients, a Hürthle cell cytologic pattern was associated with a malignant thyroid nodule in 33%, and a hypercellular smear was suggestive of malignant involvement in 26% of cases. The lowest rate of malignant potential was associated with cytologic microfollicular and scant colloid alone subtype (6%).ConclusionThe results of this study show that indeterminate thyroid cytologic specimens can be subdivided into groups with different malignant risks. A microfollicular cytologic pattern in the absence of a hypercellular smear or nuclear atypia does not support a recommendation of surgical treatment. A malignant cytologic diagnosis has a high positive predictive value for detection of thyroid cancer. (Endocr Pract. 2004;10:330-334)