High Probability Of Malignancy Research Articles

Ultrasonographic alterations associated with the dilatation of mammary ducts: feature analysis and BI-RADS assessment

The purpose of this study was to analyse the lesion characteristics and the patterns of dilated ducts on ultrasonography (US) to determine the appropriateness of the Breast Imaging Reporting and Data System (BI-RADS) categories. From July 2001 to June 2006, 172 consecutive pathologically proved lesions with dilated ducts on US were reviewed retrospectively. All the lesions were classified into four types according to their US features, and in combination with the size, location, margins and number of lesions, the corresponding positive predictive values (PPVs) were obtained. Of the 172 lesions, 55 (32%) were classified as type I, 68 (40%) as type II, 14 (8%) as type III and 35 (20%) as type IV. The PPVs for malignancy were 9% for type I, 13% for type II, 43% for type III and 17% for type IV. There was a significantly higher frequency of malignancy among type III lesions than among type I (43% vs 9%, respectively, P = 0.002; chi (2) test) or type II lesions (43% vs 13%, respectively, P = 0.009; chi (2) test). Lesions with a nonsubareolar location and noncircumscribed margins had a high probability of malignancy (P < 0.001 and P = 0.03, respectively). The four types of US classifications used in our study establish reliable references for the dilated duct patterns when stratified according to BI-RADS categories, and they clarify the indications for biopsy of these lesions.

Incidental breast lesions found on computer tomography – what is their significance?

To analyze the features of non-mass-like (NML) breast lesions on ultrasound (US) and determine their corresponding malignancy rate and to stratify these lesion patterns according to US BI-RADS categories.One hundred sixty-four consecutive lesions were retrospectively classified into four types according to the US features, the corresponding positive predictive values (PPVs) were obtained. Clinical, imaging, and histopathological findings were reviewed.Among the 164 lesions, 39 (24%) were classified as type Ia, 14 (8%) as type Ib, 39 (24%) as type IIa, 19 (12%) as type IIb, 19 (12%) as type III, and 34 (21%) as type IV. The PPVs for malignancy were 21% for type Ia, 79% for type Ib, 10% for type IIa, 58% for type IIb, 16% for type III, and 21% for type IV. All NML lesions were classified as BI-RADS category 4a (type IIa), 4b (type Ia, III and IV) and 4c (type Ib and IIb) according to their PPVs. There was a significantly higher frequency of malignancy among lesions of type Ib and type IIb compared with the other types (P < 0.01 for each). Lesions with associated calcifications, presence of abnormal axillary nodes, or a mammographic finding of suspected malignancy had a higher probability of malignancy (P < 0.05 for each).US is useful in clarifying the indication for biopsy of NML lesions. The types of US classifications used in our study establish reliable references for the NML patterns when stratified according to the BI-RADS categories.

Incidence of thyroid carcinoma in fluorodeoxyglucose positron emission tomography-positive thyroid incidentalomas

Fluorodeoxyglucose (FDG) whole body positron emission tomography (PET) scan may show clinically occult second lesions. Such lesions in the thyroid are increasingly common. There are several recent reports of a high probability of malignancy in these lesions ranging from 14% to 63%. This is a retrospective review of 15,711 PET scans at a multi-disciplinary thyroid clinic at a tertiary care university medical center. Twenty-two patients were referred with thyroid PET "incidentalomas." The review included 18 FDG-PET scans, ultrasound guided fine needle aspiration biopsies, and thyroid surgery pathology. Aspiration cytology or pathology were the main outcome measures. Three patients had malignancy of the PET-positive thyroid lesions. Papillary thyroid micro carcinomas were detected in four of the specimens that showed a benign pathology of the dominant nodule. Our experience shows a 14% malignancy rate for the dominant (imaged) nodule and a total malignancy rate of 32% when the incidental micro carcinomas are included. Both of these rates are significantly lower than results published previously.

Automated analysis of contrast enhancement in breast MRI lesions using mean shift clustering for ROI selection

To evaluate a new method for automated determination of a region of interest (ROI) for the analysis of contrast enhancement in breast MRI. Mean shift multidimensional clustering (MS-MDC) was employed to divide 92 lesions into several spatially contiguous clusters each, based on multiple enhancement parameters. The ROIs were defined as the clusters with the highest probability of malignancy. The performance of enhancement analysis within these ROIs was estimated using the area under the receiver operator characteristic curve (AUC), and compared against a radiologist's final assessment and a classifier using histogram analysis (HA). For HA, the first, second, and third quartiles were evaluated. MS-MDC resulted in AUC = 0.88 with a 95% confidence interval (CI) of 0.81-0.95. The AUC for the radiologist's assessment was 0.93 (95%CI = 0.87-0.97). Best HA performance was found using the first quartile, with AUC = 0.79 (95%CI = 0.69-0.88). There was no significant difference between MS-MDC and the radiologist (P = 0.40). The improvement of MS-MDC over HA was significant (P = 0.018). Mean shift clustering followed by automated selection of the most suspicious cluster resulted in accurate ROIs in breast MRI lesions.

Calcification in breast lesions: pathologists’ perspective

Evaluation of calcification in breast lesions is a major assessment criterion for breast mammography. The morphology and distribution of the calcification are related to the histology of the lesions. Radiologically,...

PREOPERATIVE ASSESSMENT OF THYROID NODULES: ROLE OF ULTRASONOGRAPHY AND FINE NEEDLE ASPIRATION BIOPSY FOLLOWED BY CYTOLOGY

To evaluate the preoperative assessment of thyroid nodules using ultrasound studies and cytology of nodular aspirates. 2,468 patients with thyroid nodules were examined from 1999 to 2005. All patients were clinically examined and underwent ultrasonography followed by fine-needle aspiration biopsy (FNAB) and cytology. Nodules larger than 10 mm were classified ultrasonographically in a 4-tier system and received a score according to the criterion of possible malignancy. Cytological examinations were conducted independently by 2 cytologists and classified as benign (score 1), indeterminate (score 2), suspicious (score 3), and malignant (score 6). Combining both scores, an index was generated that would indicate a higher probability of malignancy (benign, doubtful, suspicious, and malignant). Thyroid surgery was performed in 274 patients. Of those, 115 patients had a score of 2 to 5 and only 8 had a histological diagnosis of thyroid cancer (6.9%). For patients with a score of 5 (n = 51), 11.5% had a malignant lesion, and 51% of the 61 patients with a score of 6 had confirmed thyroid cancer. Of the 98 patients with a combined score of 7 to 10, 99% had a histological confirmation of malignancy. The index score had a sensitivity of 94.1% and specificity of 77.5%. The overall accuracy was 85.8%. Therefore, we concluded that this methodology may improve the preoperative diagnosis of thyroid cancer in nodules larger than 10 mm. Association with other methods such as color Doppler echography, serum TSH concentration, galectin-3 expression analysis, and FDG/PET scan would be useful in avoiding the higher costs of thyroid surgical procedures.

Tumor do estroma gastrintestinal: achados clínicos, radiológicos e anatomopatológicos

OBJETIVO: Investigar e descrever os achados clínicos, radiológicos e anatomopatológicos dos tumores do estroma gastrintestinal. MATERIAIS E MÉTODOS: De dezembro de 2000 a março de 2006, 16 pacientes foram operados por tumores do estroma gastrintestinal em nossa instituição. As variáveis analisadas foram sexo e idade dos pacientes, sinais e sintomas na consulta inicial, localização e tamanho do tumor, achados radiológicos, características anatomopatológicas e a ocorrência de metástases. RESULTADOS: A população em estudo constou de nove homens e sete mulheres. Os locais de origem dos tumores primários foram o estômago (n = 5), o reto (n = 4), o intestino delgado (n = 3), o mesentério (n = 3) e o cólon sigmóide (n = 1). Tomografia computadorizada foi o principal método radiológico empregado. Massa circunscrita, de contornos lobulados e que sofre realce heterogêneo pelo meio de contraste foi o principal achado por imagem. Em nosso estudo, nove pacientes (56% dos casos) apresentaram metástases ao diagnóstico ou recorrência do tumor num período médio de dois anos e oito meses. CONCLUSÃO: O tumor do estroma gastrintestinal acomete adultos de meia-idade e idosos e deve ser lembrado no diagnóstico diferencial das massas abdominais. Diagnóstico precoce, tratamento correto e acompanhamento rigoroso são fundamentais, pois, como demonstrado em nosso trabalho, essas neoplasias apresentam alta tendência à malignidade.

Focal uptake of 18F‐fluorodeoxyglucose by thyroid in patients with nonthyroidal head and neck cancers

To evaluate the prevalence and significance of focal thyroid lesions identified by (18)F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) in patients with nonthyroidal head and neck cancers (HNC). Patients with histologically identified HNC who underwent FDG-PET and computed tomography (CT) were reviewed retrospectively. We evaluated the prevalence of patients with focal thyroid FDG uptake and the risk of malignancy and proper management in these patients. Of 689 HNC patients, 19 (2.8%) had focal thyroid FDG uptake. Of the 12 patients with a histological diagnosis by surgery or needle biopsy, 5 (41.7%) had carcinomas, 4 papillary and 1 follicular, whereas the others had benign thyroid lesions. The maximum standardized uptake value on PET was not sufficient to discriminate between malignant and benign thyroid lesions (8.4 +/- 13.2 vs. 4.2 +/- 4.0; P > 0.4). The identification of incidental thyroid diseases helped guide patient counselling and combined surgery with HNC and thyroidectomy. Focal thyroid lesions incidentally found on FDG-PET in patents with nonthyroidal HNC have a high probability of malignancy. These lesions deserve further diagnostic examination before HNC treatment to ensure adequate therapy for incidental thyroid cancers.

Basedow-Struma mit papillärem Schilddrüsenkarzinom - Zufall oder Zusammenhang?

A 41-year-old woman presented with hyperhydrosis, tremor, restlessness, sleeplessness and diarrhea. She had a tachycardia and later she developed soreness of her conjunctives. A tender goitre could be palpated. Laboratory results showed thryeotoxicosis and later elevated TRAK. Ultrasound revealed a thyroid nodule. Scintigraphic uptake was generally elevated. Graves disease was diagnosed. After 12 months of thyreostatic medication recurrence occurred and a thyroidectomy was performed. Histologically a papillary cancer was found and postoperative radioiodinetherapy was added. Due to leading symptoms of thyreotoxicosis the thyroid nodule has preoperatively not been paid enough attention to. A pathophysiologic association of Graves disease and differentiated thyroid cancer is controversely discussed but seems possible considering present literature data. Scintigraphically "cold" nodules in graves disease, as in simple nodular goitre, have a higher probability of malignancy.

Analysis of adrenal masses by 18F-FDG positron emission tomography scanning

This study aimed to analyse the characteristics of adrenal masses visible in the computerised tomography (CT) scans which have been also evaluated by 2-[18F]fluoro-2-deoxy-D-glucose positron emission tomography (18F-FDG PET), and to characterise the features of 18F-FDG PET scans associated with various adrenal endocrine tumours, especially benign functional tumours. 18F-FDG PET scans of 105 patients with adrenal masses on the CT scan were analysed. Positive uptakes in the 18F-FDG PET scans were seen in 60 malignant tumours (54 metastasic lesions, six primary adrenal cancers) and seven benign tumours. The positive predictive value of 18F-FDG PET imaging to characterise an adrenal mass as a malignant tumour was 90%; the corresponding negative predictive value to rule out malignancy was also 90%. Benign adrenal tumours were smaller than that of malignant lesions (p<0.05). The mean standardised uptake value max (SUVmax) of the metastatic lesions [8.4+/-6.5 (microCi/g)/microCi/kg] was significantly higher than that of the benign adrenal tumours [2.4+/-1.2 (microCi/g)/microCi/kg, p<0.001]. Examination of only the primary adrenal lesions revealed that all adrenocortical carcinomas, two of three cases of pheochromocytomas, three of five neuroblastomas and two of four cases of primary aldosteronism showed positive 18F-FDG uptake. In conclusion, for patients presenting adrenal masses with a high probability of malignancy, 18F-FDG PET can be used to differentiate malignant from benign adrenal lesions. However, the 18F-FDG PET uptake did not show an always consistent pattern for endocrine tumours, which was probably due to the variability inherent in 18F-FDG uptake. This study suggests that 18F-FDG PET scanning can offer supporting data to localise and characterise adrenal tumours.

Risk of Malignancy in Solid Breast Nodules According to Their Sonographic Features

The purpose of this study was to assess the risk of malignancy for each type of sonographic feature in solid breast nodules. The study included 304 patients from the Department of Gynecology and Obstetrics of the Federal University of Goiás who had solid breast nodules. A medical trainee, working under the supervision of a preceptor, obtained the sonographic images of the breast, and the features were recorded in a questionnaire. Each sonographic feature was analyzed and compared with the anatomic and pathologic findings after the lesion was excised. Of the 304 patients included in the study, 292 (96%) had a conclusive diagnosis. Among these women, 216 (74%) had benign tumors and 76 (26%) had malignant tumors. The odds ratio of malignancy in breast nodules, as calculated by multivariate analysis, was as follows: lesions without circumscribed margins, 17.02 (95% confidence interval, 5.28-54.90); lesions with heterogeneous echo texture, 7.70 (2.99-19.84); lesions with thickened Cooper ligaments, 15.61 (1.08-225.10); nodules whose anteroposterior dimension was larger than their width, 3.29 (1.09-9.96); those with an anterior echogenic rim, 2.59 (0.80-8.40); and those with posterior shadowing, 1.57 (0.62-4.01). Among the 133 cases that had all the sonographic features of a benign lesion, 3 nodules (2.3%) had a histologic diagnosis of malignant. Sonography is a diagnostic method that can help establish the differentiation between benign and malignant solid tumors. A lack of circumscribed margins, heterogeneous echo patterns, thickened Cooper ligaments, and an increased anteroposterior dimension can indicate a higher probability of malignancy in solid breast nodules.

The significance of the diagnosis of atypia in breast fine-needle aspiration.

The diagnosis of atypia in breast fine-needle aspiration (FNA) continues to be an area of debate in cytology practice. The aim of this study was to assess the clinical significance of this term and to evaluate potential morphological criteria, which would determine the patient's outcome. A computer-based search was carried out to retrieve breast FNAs performed between 1990 and 2000 that were diagnosed as atypical. Cases followed by surgical resection were reexamined for the presence of morphological features potentially differentiating benign and malignant lesions. Out of 1,568 breast FNAs, there were 64 cases (4%) with a diagnosis of atypia. Thirty-eight cases had surgical follow-up material that revealed malignancy in 14 cases (37%) and benign lesions in 24 cases (63%). The benign diagnostic categories included fibrocystic change (12/24), fibroadenoma (3/24), tubular adenoma (2/24), and nonspecific findings (7/24). The malignant diagnoses included ductal carcinoma (9/14), lobular carcinoma (3/14), ductal carcinoma in situ (DCIS; 1/14), and tubular carcinoma (1/14). The evaluation of cytological criteria used to differentiate benign from malignant lesions (i.e., cellularity, loss of cohesion, myoepithelial cells, nuclear enlargement, nuclear overlap, prominent nucleoli) revealed significant overlap between benign and malignant cases, particularly in cases of fibroadenoma, tubular adenoma, and proliferative breast disease. The surgical follow-up of four hypocellular cases revealed lobular carcinoma in two cases and ductal carcinoma in the remaining two cases. Our study confirmed that the diagnosis of atypia is clinically significant because it is associated with a high probability of malignancy. No morphological criterion is able to reliably differentiate benign and malignant lesions in cases diagnosed with atypia. Diagnosis of atypia is particularly significant in hypocellular cases. We recommended that breast FNAs with a diagnosis of atypia be evaluated further histologically.

Transthoracic needle biopsy in the diagnosis of solitary pulmonary nodules: a survey of canadian physicians

ObjectiveTo describe Canadian physicians' opinions relative to the choice of diagnostic procedures in patients presenting with a solitary pulmonary nodule and to identify the attributes that may influence their decision. MethodsWe conducted a mailed survey among Canadian physicians including pulmonologists, thoracic surgeons, radiologists, and internists. Five hypothetical clinical scenarios designed to illustrate a wide spectrum of clinical situations (including nodules associated to very low, indeterminate, and high probabilities of malignancy in patients medically fit or unfit to undergo surgical resection) were submitted to each physician who had to choose among options of diagnostic procedures and to estimate the pretest probability of malignancy. ResultsThe survey response rate was 47%. Overall, the physicians tended to overestimate the probability of malignancy. Twenty-eight percent of the respondents would have ordered a transthoracic needle biopsy in a medically fit patient presenting with a very low probability (< 2%) of malignancy, whereas 53% would have done so in a medically fit patient presenting with a very high probability (75%) of malignancy. In a regression analysis, the significant predictors of the use of transthoracic needle biopsy were (1) the pretest probability of cancer, (2) the patient's operability, (3) specialty (pulmonologists and thoracic surgeons being less likely to order a transthoracic needle biopsy than radiologists), and (4) the respondent's gender. ConclusionsThere are widespread variations in clinical opinions among Canadian physicians regarding the use of transthoracic needle biopsy in the investigation of solitary nodules. Hypothetical transthoracic needle biopsy was often preferred when the result was unlikely to affect patient management.

Noncardiac findings on dual-isotope myocardial perfusion SPECT

Background This study examined the frequency of reporting noncardiac findings (NCFs), such as malignancies from inspection of raw projection images with dual-isotope single photon emission computed tomography (SPECT) perfusion imaging, which could potentially be of greater clinical importance than myocardial perfusion imaging alone. Dual-isotope (ie, rest thallium 201 and stress technetium 99m sestamibi [MIBI] or Tc-99m tetrofosmin [TET]) SPECT myocardial perfusion imaging combines multipotential tracers for noncardiac purposes (Tl-201 for renal or splenic imaging, inflammation, or lymphoma and MIBI or TET for hepatobiliary imaging and detecting increased mitochondrial number or activity in neoplastic processes). These images are optimally interpreted with cinematic inspection of the raw projection data, but this may not be practiced uniformly in every laboratory. Methods and results We reviewed 12,526 computer-generated text reports of dual-isotope perfusion SPECT studies from a 6-year period for NCFs. NCFs were categorized by organ and by probability of malignancy: high (eg, focal breast or lung uptake of MIBI or TET), intermediate (eg, lymph node uptake or thyroid abnormalities), or low (eg, filling defects in liver, kidney, spleen, or gall bladder; ascites; or pleural effusions). Confirmatory imaging studies or clinical confirmation for each NCF was sought. There were a total of 207 NCFs identified in 180 reports (1.7% of reports, ranging from 0% to 2.8% of reports of individual interpreters). Of these, 107 NCFs were unsuspected before SPECT; 24% were considered at high probability for malignancy, and 24% were considered intermediate in likelihood of malignancy. Follow-up data were available for 178 NCFs, confirming 88% of these findings, including 82% of breast foci, 62% of lung foci, 86% of hepatobiliary/spleen abnormalities, and 94% of renal abnormalities. The probability of malignancy was highest (82%) in breast or lung foci in which uptake of both Tl-201 and the Tc-99m–labeled agent was present. Conclusions In patients referred for evaluation of myocardial perfusion, NCFs are unusual and require systematic and careful inspection of projection images for their detection. With Tl-201, TET, MIBI, or dual-isotope imaging, detecting and reporting NCFs may occasionally result in life-saving early cancer identification.

First experience with a new dedicated ultrasound system for computer-guided large-core breast biopsy.

We describe a new dedicated ultrasound system for computer-guided large core breast biopsy (LCBB) and report our first clinical experience in 45 female patients. After an initial 30 biopsy procedures on a US breast phantom, LCBB using this new system was performed in 45 non-palpable surgically verified breast lesions. All biopsies were performed by the same radiologist using 14-gauge long-throw biopsy needles. Histological results following LCBB were compared with open surgical biopsy. Procedure time and any complication arising was registered in all procedures. Biopsies using this prototype were successful and yielded sufficient material in all 45 lesions. There were 23 benign and 22 malignant lesions with complete histological agreement between LCBB and open surgical biopsy in 44 of the 45 lesions. In one invasive ductal cancer the pathologist could only state high probability of malignancy but not give a definite diagnosis. Besides one case with early termination due to decreased visibility of the target lesion, no technical complications were noted. Slight vasovagal reactions were seen in 4 patients but did not alter the histological results. The average procedure time was 30+/-2.7 min. This new dedicated US system for computer-guided LCBB is an accurate and safe method for diagnosing breast lesions. Although this new system may have no major impact for US-guided LCBB experienced physicians, it might be a promising alternative for the non-skilled physician to currently available breast biopsy techniques.

The role of F-18FDG PET in thyroid cancer

Hypofunctioning nodules on scintiscan using Tc-99m Pertechnetate or I-123 have a higher probability of malignancy compared to eu- or hyperfunctioning nodules. However, in the preoperative assessment of thyroid nodules, ultrasonography and ultrasonography guided fine needle aspiration biopsy play the most important role, especially for papillary thyroid cancer. The problem of differentiating follicular adenoma from highly differentiated follicular carcinoma however remains. Also the additional use of a multi tracer imaging strategy (Tl-201/Tc-99m subtraction scan, Tc-99m Sestamibi, Tc-99m Tetrofosmin dual phase scintigraphy) has not solved this problem. Although it is unlikely, the question whether FDG PET is able to give a better differentiation between benign and malignant tumours in the preoperative assessment of thyroid nodules is not answered up to now. In contrast to preoperative diagnostics, FDG PET is of great value in the postoperative follow up of differentiated thyroid cancer. In case of elevated serum thyroglobulin but negative I-131 WBS FDG PET is the method of choice to detect I-131 negative recurrences and metastases. FDG uptake in metastases from differentiated thyroid cancer is correlated to low differentiation and maybe bad prognosis. There is also evidence that FDG PET may have a role in the follow up of anaplastic and especially in medullary thyroid cancer in the future.

The value of Tc-99m tetrofosmin thyroid scintigraphy in patients with nodular goiter.

The aim of this study is to investigate the value of Tc-99m tetrofosmin (Tc-99m-TF) in conjunction with conventional Tc-99m-pertechnetate (Tc-99m-P) scintigraphy in the differentiation of malignant nodules from benign thyroid nodules. Forty-two patients [(32 females, 10 males; mean age 41 +/- 13 years; twenty-two multinodular goiter (MNG) patients with 58 nodules and 20 solitary thyroid nodules (STN)] were included in the study. Thyroid scintigraphy with Tc-99m-P and Tc-99m-TF, thyroid ultrasonography and fine needle aspiration cytology (FNAC) were performed. After i.v. injection of 370-550 MBq Tc-99m-TF, images were obtained at 15 minutes and evaluated semiquantitatively by using a five point (0-4) scoring system. Four patients with a hypoactive STN, and 1 patient with a hypoactive MNG was found to have thyroid malignancy by histopathological examination; 2 of these patients had false negative benign FNAC results. The tetrofosmin uptake score (TUS) was 2-3-3-3 and 3 in these 5 malignant nodules. Five hyperactive (hot or warm) STN with benign FNAC had a TUS of 2-3-3-3-3. All hypoactive (cold) MNG nodules with benign FNAC (n = 21) had TUS < or = 2. Our preliminary results suggest that follicular adenomas and thyroid cancers have higher tetrofosmin uptake than benign colloidal goiter nodules. Mitochondrial sequestration of tetrofosmin in benign or malignant follicular cells that proliferate more rapidly than normal follicular cells and/or hypervascularity may be responsible for this. The use of Tc-99m-TF in conjunction with Tc-99m-P thyroid scintigraphy will be helpful in the evaluation of patients with nodular goiter (NG). In patients with a STN, a hypoactive nodule with a high TUS has a higher probability of malignancy; whereas a hyperactive nodule with a high TUS is a follicular adenoma. In patients with MNG, a hypoactive nodule with a high TUS may be suggestive of malignancy despite a benign FNAC result. We think that further studies with Tc-99m-TF are required to confirm these results.

Likelihood of Malignancy in a Solitary Pulmonary Nodule: Comparison of Bayesian Analysis and Results of FDG-PET Scan

To compare the probability of cancer in a solitary pulmonary nodule using standard criteria with Bayesian analysis and result of 2-[F-18] fluoro-2-deoxy-D-glucose-positron emission tomographic (FDG-PET) scan. A university hospital and a teaching Veteran Affairs Medical Center. Retrospective analysis of 52 patients who had undergone both CT scan of the chest and a FDG-PET scan for evaluation of a solitary pulmonary nodule. FDG-PET scan was classified as abnormal or normal. Utilizing Bayesian analysis, the probability of cancer using "standard criteria" available in the literature, based on patient's age, history of previous malignancy, smoking history, size and edge of nodule, and presence or absence of calcification were calculated and compared to the probability of cancer based on an abnormal or normal FDG-PET scan. Histologic study of the nodules was the gold standard. The likelihood ratios for malignancy in a solitary pulmonary nodule with an abnormal FDG-PET scan was 7.11 (95% confidence interval [CI], 6.36 to 7.96), suggesting a high probability for malignancy, and 0.06 (95% CI, 0.05 to 0.07) when the PET scan was normal, suggesting a high probability for benign nodule. FDG-PET scan as a single test alone was more accurate than the standard criteria and standard criteria plus PET scan in correctly classifying nodules as malignant or benign. FDG-PET scan as a single test was a better predictor of malignancy in solitary pulmonary nodules than the standard criteria using Bayesian analysis. FDG-PET scan can be a useful adjunct test in the evaluation of solitary pulmonary nodules.

Large cystic/solid thyroid nodules: a potential false-negative fine-needle aspiration.

False-negative fine-needle aspiration (FNA) biopsy results of thyroid nodules are of particular concern because they imply missed malignant lesions. The purpose of this study was to identify characteristics of thyroid nodules that may lead to false-negative cytologic interpretation after FNA. We reviewed 90 consecutive patients who underwent preoperative FNA of thyroid nodules followed by thyroid surgery during a period of 27 months, including their clinical data, type and size of thyroid nodule, FNA cytology results, and final pathology report of the surgical specimen. Thyroid nodules that had the highest probability of malignancy were those that were large (3 cm or larger), cystic/solid, or large and cystic/solid. The overall false-negative rate for preoperative FNA was 11%. Large, cystic/solid, and thyroid nodules with both characteristics had false-negative rates of 17%, 25%, and 30%, respectively, compared with 0%, 9%, and 17% for small (less than 3 cm), solid, and solid nodules 3 cm or larger, respectively. Because of the high prevalence of malignancy in thyroid nodules that are large (3 cm or larger), cystic/solid, or large and cystic/solid and the high false-negative rate of FNA in diagnosing these lesions, thyroid lobectomy for diagnosis should be strongly considered in these patients even when FNA cytologic finding is interpreted as benign.

Stereotactic breast biopsy.

The substantial majority of questionable lesions detected by mammography are benign, and there is growing interest among health care professionals and patients in alternatives to surgical biopsy for diagnosing these lesions. Stereotactic breast biopsy is an x-ray guided method for localizing and sampling breast lesions discovered on mammography and considered to be suspicious for malignancy. Its use in sampling small, nonpalpable breast lesions has been investigated over the past 15 years, using fine-needle aspiration for cytology and, more recently, core-needle biopsy for histology. Multiple series comparing stereotactic biopsy with surgical biopsy have shown that stereotactic techniques accurately sample small lesions and have a sensitivity of 90 to 95 percent for breast cancer detection. State-of-the-art stereotactic breast biopsy is comparable in sensitivity to surgical biopsy, and the procedure is quicker, cheaper, and easier than the standard practice of preoperative, mammographically guided localization followed by surgical biopsy. In an age of miniaturization, stereotactic techniques provide miniature breast biopsies. The University of Chicago acquired the first prone stereotactic table in the United States in 1986, and we have found stereotactic breast biopsy to be a very good alternative for certain lesions that would otherwise require surgical biopsy for diagnosis. Most lesions (70 percent) sent to conventional biopsy at the University of Chicago between 1986 and 1989 were graded by observers as being in a low-suspicion category (less than 10 percent chance of malignancy based on mammographic findings), and the positive malignancy yield of this category of lesions was seven percent. These lesions were also examined with stereotactic fine-needle aspiration performed as a "piggy-back" procedure to the needle localization for surgery. The results of this study have led us to use stereotactic biopsy rather than surgical biopsy for low-suspicion lesions since then. We currently use stereotactic breast biopsy for about half the nonpalpable lesions considered for breast biopsy at our institution and find it to be reliable and readily accepted by informed patients. The introduction of automated core-biopsy guns has escalated interest in the technique, due to increased confidence in the histologic samples obtained and the ability to make specific benign diagnoses more frequently. Some centers have extended the potential use of stereotaxis to virtually all suspicious mammographic lesions, including those with a high probability of malignancy, to plan definitive surgery. Based on current estimates, there are now over 1,000 centers either investigating or using stereotactic biopsy for occult breast lesions.