[Histology, cytology and molecular diagnostics of lung cancer]. / Histologie, Zytologie und Molekulardiagnostik des Lungenkarzinoms.

Traditionally, tissue-based histopathological approaches play an outstanding role in the diagnostics of lung cancer. The importance of these methods has become even more important with the introduction of individualized treatment options. Lung cancer is basically classified following the World Health Organization (WHO) guidelines using conventional histology and immunohistochemistry. For individual entities in certain clinical stages, the evaluation of the tumor biological profile serves as the basis for the so-called individualized treatment or precision medicine where changes in the intracellular signal transduction mechanisms are the target of therapeutic efforts or the therapy tries to re-initiate immunogenic reactions of the autologous immune system against the tumor cells. The histopathologic overexpression of receptors as well as various genetic and epigenetic changes (e.g. inversion, translocation and methylation) are the key players for predictive approaches to uncover the individual tumor biology and to make treatment decisions.

[Lymphocytic myocarditis in a patient with metastatic clear cell renal cell carcinoma treated with Nivolumab]. / Lymphozytäre Myokarditis unter Nivolumabtherapie bei metastasiertem klarzelligen Nierenzellkarzinom.

Immune checkpoint inhibitors against the PD-1 protein offer a new therapy option for many solid cancers. We report a patient with metastatic renal cell cancer treated with Nivolumab. As a rare immune-mediated adverse event, we describe a fatal lymphocytic myocarditis two weeks after starting immune therapy. The cause of death was first diagnosed at autopsy. This case report underlines the importance and need of clinical autopsies as an instrument of quality assurance and detection of rare therapy-induced adverse effects.

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia diagnosed by transbronchial lung cryobiopsy: a case report.

BACKGROUND: Micronodular lesions are common findings in lung imaging. As an important differential diagnosis, we describe a case of diffuse idiopathic pulmonary neuroendocrine cell hyperplasia; it is notable that the diagnosis of diffuse idiopathic pulmonary neuroendocrine cell hyperplasia is often delayed. This case provides supporting evidence to establish lung biopsy by cryotechnique as the option of first choice when considering a diagnostic strategy for micronodular lung lesions. CASE PRESENTATION: We report a case of a 65-year-old white woman who presented with obstructive symptoms of chronic coughing and dyspnea confirmed by conventional lung function tests. A computed tomography scan presented disseminated micronodules in all the lobes of her lungs. With the help of bronchoscopic cryobiopsy it was possible to obtain a high yield sample of lung parenchyma. On histologic examination, the micronodules correlated with a diffuse neuroendocrine cell hyperplasia. In the context of clinical symptoms, radiological aspects, and histomorphological aspects we made the diagnosis of a diffuse idiopathic pulmonary neuroendocrine cell hyperplasia. Obstructive symptoms were treated with inhaled steroids and beta-2-mimetics continuously. A comparison between current computed tomography scans of our patient and scans of 2014 revealed no significant changes. Last ambulatory checks occurred in January and May of 2016. The course of disease and the extent of limitation of lung function have remained stable. CONCLUSIONS: The diagnosis of diffuse idiopathic pulmonary neuroendocrine cell hyperplasia is best made in a multidisciplinary review including clinical presentation, lung imaging, and histomorphological aspects. This report and current literature indicate that transbronchial lung cryobiopsy can be used as a safe and practicable tool to obtain high quality biopsies of lung parenchyma in order to diagnose micronodular lesions of the lung.

Intra-patient comparison of parietal pleural biopsies by rigid forceps, flexible forceps and cryoprobe obtained during medical thoracoscopy: a prospective series of 80 cases with pleural effusion.

BACKGROUND: There is only few data available on the use of cryotechnique during medical thoracoscopy. METHODS: Medical thoracoscopy was performed in consecutive patients with pleural effusion. Prospectively, biopsies were taken by rigid forceps, flexible forceps and cryoprobe. Specimen size, depth and diagnostic yield were compared. RESULTS: 80 Patients were included. 408 biopsies were taken (205 rigid biopsies, 104 flexible biopsies, 99 cryobiopsies). Mean surface area of rigid biopsies was 22.6 ± 20.4 mm(2) (flexible biopsies: 7.1 ± 9.3 mm(2), cryobiopsies: 14.4 ± 12.8 mm(2)). Rigid biopsies were significantly larger than cryobiopsies (p < 0.001) and flexible biopsies (p < 0.001), crybiopsies were significantly larger than flexible biopsies (p < 0.01). A deep biopsy containing fatty tissue was harvested in 63 % of rigid biopsies (cryobiopsy: 49.5 % flexible biopsy: 39.5 %). In 79/80 cases (98.7 % 95 % CI cannot be calculated) a diagnosis was obtained by rigid biopsy (cryobiopsy: 73/80 cases (91.3 % 95 % CI 86.0 - 96.5 %), flexible biopsy: 74/80 cases (92.5 % 95 % CI 88.6 - 97.4 %)). Diagnostic yield achieved with cryobiopsies was inferior to the yield of rigid biopsies (Difference: 12.7 %), but non-inferior to flexible biopsies (Difference: 6.5 %). CONCLUSION: Cryobiopsies in medical thoracoscopy are safe with high diagnostic yield, non-inferior to flexible biopsies with increased tissue quantity and quality. Cryotechnique can develop an important role in medical thoracoscopy in the near future when rigid thoracoscopy is not available.

MDM2 is an important prognostic and predictive factor for platin-pemetrexed therapy in malignant pleural mesotheliomas and deregulation of P14/ARF (encoded by CDKN2A) seems to contribute to an MDM2-driven inactivation of P53.

BACKGROUND: Malignant pleural mesothelioma (MPM) is a highly aggressive tumour that is first-line treated with a combination of cisplatin and pemetrexed. Until now, predictive and prognostic biomarkers are lacking, making it a non-tailored therapy regimen with unknown outcome. P53 is frequently inactivated in MPM, but mutations are extremely rare. MDM2 and P14/ARF are upstream regulators of P53 that may contribute to P53 inactivation. METHODS: A total of 72 MPM patients were investigated. MDM2 immunoexpression was assessed in 65 patients. MDM2 and P14/ARF mRNA expression was analysed in 48 patients of the overall collective. The expression results were correlated to overall survival (OS) and progression-free survival (PFS). RESULTS: OS and PFS correlated highly significantly with MDM2 mRNA and protein expression, showing a dismal prognosis for patients with elevated MDM2 expression (for OS: Score (logrank) test: P⩽0.002, and for PFS: Score (logrank) test; P<0.007). MDM2 was identified as robust prognostic and predictive biomarker for MPM on the mRNA and protein level. P14/ARF mRNA expression reached no statistical significance, but Kaplan-Meier curves distinguished patients with low P14/ARF expression and hence shorter survival from patients with higher expression and prolonged survival. CONCLUSIONS: MDM2 is a prognostic and predictive marker for a platin-pemetrexed therapy of patients with MPMs. Downregulation of P14/ARF expression seems to contribute to MDM2-overexpression-mediated P53 inactivation in MPM patients.

Chromogenic in situ hybridisation (CISH) is a powerful method to detect ALK-positive non-small cell lung carcinomas.

AIM: We assessed the potential of a chromogenic in situ hybridisation (CISH) assay in comparison with quantitative reverse transcription (RT)-PCR (qPCR) to detect anaplastic lymphoma kinase (ALK) break apart-positive lung carcinomas. METHODS: Dual-colour CISH using a break apart probe for the ALK gene on 2p23 was performed with 181 formalin-fixed, paraffin-embedded tissue and agar block sections from 175 cases of non-small cell lung carcinomas (NSCLC). Stained slides were analysed with a standard bright-field microscope at 1000× magnification by counting signals from 60 non-overlapping nuclei from three different tumour areas. Samples with ≥15% of positive nuclei were judged as ALK break apart-positive. All samples were simultaneously analysed by qPCR for EML4-ALK to validate CISH results, and positive samples were subject to Sanger sequencing. RESULTS: CISH was successful with 173 of 181 hybridised samples (96%), and seven ALK break apart-positive cases were detected. CISH signals were specific and distinct for both colours. All positive cases were confirmed by qPCR and Sanger sequencing, and concordance between CISH and qPCR was 100%. Nearly all samples (9/10) which failed by qPCR were accessible to CISH analysis. CONCLUSIONS: CISH is a very reliable, convenient and inexpensive method to detect ALK-positive NSCLC. CISH success rate is comparably high as with qPCR, and it detects all ALK break apart events in a single assay. It is of special value when RNA quality is poor, or when small biopsies with a very limited amount of tumour cells have to be analysed.

Characterization of metal-tagged antibodies used in ICP-MS-based immunoassays.

A detailed characterization of metal-tagged antibodies is the prerequisite for the implementation of quantitative concepts in inductively coupled plasma-mass spectrometry (ICP-MS)-based bioanalysis or future medical diagnosis. In this paper, the common modification with bifunctional ligands containing maleimide residues as a reactive group was investigated in detail via size exclusion chromatography (SEC)-ICP-MS and liquid chromatography-time-of-flight (LC-TOF)-MS to determine the preservation of the antibody structure after tagging. Mouse monoclonal IgG modified with metal-coded tags (MeCATs) was used as a model system. Several antibody fragments were identified carrying different numbers of metal tags. In a second step, a functionality test was performed with isolated fragments where the antigen specificity was tested in a dot blot immunoassay.

[Aneurysmal bone cyst of the ethmoid sinus and skull base in a 3-year old child: a rare location of a benign bone lesion]. / Aneurysmatische Knochenzyste der Rhinobasis bei einem 3-jährigen Kind: Seltene Lokalisation einer benignen Knochenläsion.

Aneurysmal bone cyst is a benign osteolytic lesion in childhood and adolescence which primarily arises in metaphyseal long bones. Its presence in bones of the skull base is very rare. In a 3-year old girl presenting with proptosis, MRI demonstrated a well-defined displacing growing mass in the ethmoid sinus, orbita and anterior fossa. The histopathologic examination of biopsy specimens confirmed an aneurysmal bone cyst. Despite radical surgery the child suffered from two recurrences of the lesion in the first year after initial diagnosis. There has been no subsequent recurrence during the last 3 years. Since this lesion is rarely seen at the skull base, is difficult to differentiate clinically and by histopathology and may take an abnormal course, it is described in this case report to emphasize that it should be included in the differential diagnosis of ENT tumors at this location.

A 62-year-old woman with bilateral pleural effusions and pulmonary infiltrates caused by extramedullary hematopoiesis.

A 62-year-old female presented with a 1-month history of irritating cough and increasing dyspnea. A chronic idiopathic myelofibrosis had been diagnosed 5 years ago. CT of the chest and abdomen showed bilateral pleural effusions with a thickened pleura, nodular infiltrations in both lungs, enlarged intraabdominal lymph nodes and splenomegaly. Pleuroscopy (medical thoracoscopy) on the left side revealed dense tumorous nodules mainly on the posterior chest wall pleura, but also on the diaphragm and the lung. Biopsies taken from the chest wall pleura revealed extramedullary hematopoiesis (EMH) with abnormal megakaryocytes as well as myeloid and erythroid precursors. After unsuccessful tetracycline pleurodesis, talcum slurry was instilled via the chest tube without recurrence of the pleural effusion. Furthermore, treatment with hydroxyurea was started, and the disease regressed and then remained stable over the next 24 months. In conclusion, the pleuropulmonary findings were caused by EMH due to chronic idiopathic myelofibrosis. The definite diagnosis was established by pleuroscopy followed by successful pleurodesis with talc slurry, after tetracycline pleurodesis had failed.

The axillocoronary bypass. Blood flow and short-term graft histology in a porcine model.

BACKGROUND: Bypass grafts arising from the axillary artery may be indicated for complications during minimally invasive direct coronary artery bypass grafting, for redo operations and for management of a severely atherosclerotic ascending aorta. As basic data research on this technique is scanty, we investigated intraoperative function and postoperative morphology of axillocoronary bypass grafts in a porcine model. METHODS: Thirteen German domestic pigs received an axillocoronary vein graft (Group I, n=7) or an aortocoronary vein graft (Group II, n=6) to the left anterior descending artery. In Group I the proximal anastomosis was performed to the left axillary artery, and after partial rib resection the graft was brought transpleurally to the target vessel. In both groups the coronary anastomosis was carried out on the beating heart without cardiopulmonary bypass. Graft flow was measured using transit time ultrasonic flow probes. RESULTS: Intraoperatively all grafts showed a typical diastolic flow profile. Stable graft flow was lower in axillocoronary bypass grafts: 47 (30-60 mL/min) in Group I and 65 (35-126 mL/min) in Group II (p=0.005). Flow given as percentage of cardiac output, however, did not differ between the two grafts: 0.9 (0.6-1.2%) in Group I and 1.2 (0.8-2.4%) in Group II (p=NS). At day 4 after surgery there was no clear histologic predilection site for microtrauma and early degenerative changes in the axillocoronary graft. CONCLUSIONS: Axillocoronary bypass flow compares well with flow in the aortocoronary graft. Microtrauma after implantation and early degenerative changes in the axillocoronary vein bypass are not particularly impacted by the thoracic entry site.

Computer-assisted image analysis-derived intermediate endpoints.

The development of prostatic lesions undergoes a slow progression. To establish efficacy of chemopreventive intervention it is therefore necessary to define surrogate endpoint biomarkers. Such biomarkers should be sensitive in their ability to indicate response. They should be objective, ie, the result of measurement, and numerically defined so that a statistical validation of response is possible. They should be able to indicate not only a halt of progression of a lesion, but also a reversal of progression. The spatial and statistical distribution of nuclear chromatin in the secretory and luminal cells in prostatic intraepithelial neoplastic lesions has been shown to be well defined. It can be represented by a set of features. These have been used to define a progression curve along which progression or regression of a lesion can be assessed. One could define a fixed endpoint, or one might choose to accept a statistically significant regression along the progression curve as criterion for chemopreventive efficacy. Expected difficulties could arise from lesion heterogeneity, as it would affect the sampling, and from multifocal lesions of differing progressions. Lesion heterogeneity thus limits the precision with which regression could be detected. These problems might be partially overcome by observations taken in histologically normal appearing regions of the prostate. The nuclear chromatin pattern of secretory cell nuclei measured in such tissue regions from prostates harboring intraepithelial or malignant lesions has been shown to exhibit distinctive changes from the chromatin pattern seen in secretory cell nuclei from prostates free from any such lesions. These changes appear to be expressed in the tissue up to a substantial distance from a lesion. The expression of changes in the nuclear chromatin suggests the existence of an intraepithelial preneoplastic lesion that can be detected by biomarkers, but which is not apparent from visual microscopic inspection. Since chemoprevention might be expected to be most effective at the earliest stages of lesion development, the assessment of such early alterations is seen as highly relevant to efforts to validate the efficacy of chemopreventive intervention.

Infliximab in severe steroid-refractory ulcerative colitis: a pilot study.

Tumor necrosis factor-alpha (TNF alpha)-neutralization by infliximab has previously proven efficacious in chronic active Crohn's disease (CD). We performed an open-label pilot study of a single infusion of 5 mg/kg infliximab in six patients with severe active, steroid-refractory ulcerative colitis (UC). Clinical activity was evaluated according to Lichtiger on days -1, day 7, and day 28. Colonoscopy with biopsy was performed on day -1 and day 7. All patients showed marked clinical improvement by day 7 (Lichtiger score 16.3 +/- 0.4 [day -1] vs 4.8 +/- 0.7 [day 7], p < 0.0001). Four of six patients had long-term remission (Lichtiger score 7.7 +/- 2.2 [day 28], P < 0.01 compared to day -1), with a median follow-up of 5.5 months. Colonoscopy confirmed significant healing of endoscopic lesions. The inflammatory infiltrate disappeared on H&E stains, with a marked reduction in infiltrating neutrophils. Semiquantitative evaluation of T and B lymphocytes and macrophages by immunohistochemistry did not reveal major differences compared to pre-treatment. Apoptotic cells in the mucosa were reduced on day 7. Our data point toward a novel efficacious treatment option in severe steroid-refractory UC and raise the need for controlled trials.

Diagnostic effect of an improved preembedding method of prostate needle biopsy specimens.

The authors compared the influence of a conventional and an optimized submitting method of prostate core needle biopsy specimens on the frequency of cancer detected and the pathologic characteristics of the adenocarcinoma bearing biopsy specimens. The patients included were part of the prostate-specific antigen (PSA) screening program of Tyrol/Austria. Of the systematic core needle biopsy specimens from 500 unselected men obtained within 1 year from the Urological Department, University of Innsbruck, the core biopsy specimens of 250 cases were submitted conventionally, floating free in formalin-filled containers, whereas the biopsy specimens of the other 250 cases were stretched and orientated between 2 meshes in tissue cassettes at the time of biopsy before formalin fixation. On 136 cases diagnosed as adenocarcinoma the number and the length of cores as well as number of the cores involved by cancer and the tumor size were morphometrically determined. The diagnosis of benign prostatic hyperplasia, isolated high-grade prostatic intraepithelial neoplasia (PIN), atypical foci suspicious for cancer, and carcinoma was made in 66%, 5.6%, 4.8%, and 23.6% after conventional submission and in 61.6%, 6.4%, 1.2%, and 30.8% of the cases after optimized preembedding respectively. In the adenocarcinoma cases the optimizedly preembedded material showed higher mean total core length (126.5 mm versus 93.9 mm; P < .0001), a higher mean total tumor length (14.1 mm versus 8.6 mm; P = .01), and more cores involved by cancer (2.9 versus 2.4; P = .01) compared with the conventionally worked-up biopsy specimens. Optimized preembedding of core needle biopsy specimens in tissue cassettes could be quickly and routinely done by the assistance of the urologists at the time of biopsy. The significant improvement of the histologic yield of optimizedly preembedded prostatic needle biopsy specimens led to a higher frequency of cancer diagnosis, a reduction of cases with atypical foci suspicious for cancer and a significantly lower number of cases with only 1 core biopsy involved by cancer.

Radical prostatectomy: the value of preoperative, individually labeled apical biopsies.

PURPOSE: Involvement of the prostatic apex with adenocarcinoma is a relatively common finding, as is a positive surgical margin at this location. We evaluated whether a positive apical core biopsy provides preoperative information that may be used as a basis for the subsequent surgical approach in individuals. MATERIALS AND METHODS: We evaluated apical prostate cancer in 240 individually labeled, preoperative apical core biopsies and the corresponding prostatectomy specimen in 120 patients who underwent radical prostatectomy for clinically localized prostate cancer. Sensitivity, specificity, and positive and negative predictive values were calculated for the ability of an individual apical core to predict the side of tumor in the surgical specimen using 2 x 2 contingency tables. Moreover, univariate subset analysis was done for positive biopsies to assess the ability of histopathological characteristics, including Gleason score, cancer length, percent of cancer in the core and distance of cancer from the inked rectal core end, to predict a positive surgical margin at the apex. RESULTS: The positive predictive value of a single positive apical core for identifying tumor location correctly in the prostatectomy specimen was 71.1%, while absent cancer in the apical biopsy had a negative predictive value of 75.5%. Sensitivity was 44.5% for a positive biopsy core. In this context the predictive value of an individual positive apical core biopsy was only 28.8% for predicting surgical margin positivity at the apex. CONCLUSIONS: Cancer and its histopathological characteristics in an individual core biopsy failed to predict apical tumor involvement as well as a positive apical margin at subsequent radical prostatectomy.

Optimized preembedding method improves the histologic yield of prostatic core needle biopsies.

BACKGROUND: The aim of this study was to optimize the core shape of prostatic core needle biopsies using a novel preembedding method, and to investigate the influence of the number of cores per tissue block on the histologic yield per section level. METHODS: Twenty-four core needle biopsies were taken from a fresh prostatectomy specimen, using an 18-gauge needle. Twelve core needle biopsies were conventionally fixed floating free in formalin-filled containers, whereas 12 biopsies were stretched between two nylon meshes, and placed in tissue cassettes before fixation. The total number of tissue sections per paraffin block necessary for complete workup of the tissue was determined. Using image analysis, the relation of the area of every fifth section level was calculated in relation to the total projected area of the biopsies. Both methods of tissue processing were compared for both parameters. RESULTS: In contrast to the curved biopsies after conventional processing, the optimized preembedding method generally led to stretched cores after fixation and embedding. This method led to a 100% decrease in total number of tissue sections necessary for complete workup and to higher percentages of the tissue amount per section level compared to the total projected core area. These parameters were also influenced by the number of cores per paraffin block, but to a minor degree. CONCLUSIONS: This study shows that optimized preembedding of prostatic needle biopsies improves the histologic yield per section level. The continuous occurrence of representative sections could improve diagnostic accuracy in the histological examination of prostatic core needle biopsies.

Acceptance of telepathology in daily practice.

The availability of pathology services differs greatly in our environment. Although pathology would be especially suitable for being practised at a distance by transporting digital image information, the spread of telepathology into everyday work still is relatively slow. The article describes the situation of diffusion of this innovative technology by reviewing the literature and discussing this in context to data based on questionnaires dealing with the acceptance of telepathology. The current situation of telepathology can be discussed by five items for innovation spead: (1) communication and influence; (2) economic costs and benefits; (3) knowledge barriers and learning; (4) feasibility of techniques offered for the demands of the users; (5) clarification of the legal status and other factors concerning international collaboration. All these head lines do not represent realistic obstacles for the more widespread use of telepathology. The real drawbacks may therefore be found behind certain professional habits of pathologists. The most important causes may be that (a) telediagnosis is not as easy as it may seem at the first glance; (b) telepathology is seen as a potential highway to a world-wide competition of pathology service providers. As soon as these mostly unjustified prejudices are corrected and telepathology is percepted as additional technique in pathology, it will become a diagnostic tool as common and as useful as the telephone.

Mean weighted nuclear volumes in colonic adenocarcinomas. Evaluation of prognostic significance.

OBJECTIVE: To investigate the correlation of stereologically estimated mean weighted nuclear volumes of tumor cell nuclei (MWNV) with other prognostic factors and survival in colonic adenocarcinomas. STUDY DESIGN: The study group consisted of 42 patients with colonic adenocarcinomas who were treated by a standardized protocol and had a mean follow-up of 89 months. The point sample intercepts method was used to estimate MWNV. In addition, immunohistochemical expression of p53 and Ki-67 was evaluated semiquantitatively. RESULTS: The calculated nuclear volumes correlated significantly with histologic grading and with the extent of tumor progression (organ confined/nonorgan confined). There was no correlation with p53 expression or proliferative activity determined by MIB-1 positivity. No correlation could be demonstrated with sex, age or clinical outcome of the patients. CONCLUSION: Assessment of MWNV in colonic adenocarcinomas does not provide additional information concerning the clinical course.

Quantitative assessment of bladder cancer by nuclear texture analysis using automated high resolution image cytometry.

The aim of this study was to investigate the possibility of identifying urothelial neoplasia by nuclear chromatin texture feature analysis using high resolution image cytometry to improve the diagnostic accuracy of cytologic examination in the detection and monitoring of bladder cancer. Touch imprints of transurethral resection material of 56 control group (CG) cases of nonmalignant urothelium and 94 tumor group (TG) cases of bladder cancer were analyzed. The specimen collection was divided randomly into a training set and a test set. Cells were stained specifically for DNA by the Feulgen method. Only diploid cell nuclei were analyzed from both groups. A discriminator comprised of three nuclear texture features was derived from the training set of cases to separate CG from TG cases. This discriminator was then applied to the independent test set. CG cases were separated from TG cases with a sensitivity of 97% and a specificity of 95% on the independent test set of cases. When dividing TG cases into high-risk and low-risk groups, sensitivity in the low-risk group was 93%. None of the high-risk cases was misclassified (sensitivity, 100%). This retrospective investigation demonstrates that by high-resolution image cytometry it is possible to distinguish between urothelial neoplasia and normal urothelium with high reliability when examining diploid cell nuclei only. This method is superior to DNA ploidy analysis using image or flow cytometry and may become clinically relevant as a supplement to conventional cytologic examination. These promising results should be confirmed on cytologic preparations derived from bladder washings or voided urine.

Nuclear chromatin texture analysis of nonmalignant tissue can detect adjacent prostatic adenocarcinoma.

BACKGROUND: The aim of this study was to investigate the possibility of identifying prostatic adenocarcinoma by nuclear chromatin texture feature analysis of adjacent histologically benign-looking tissue. METHODS: Two hundred and forty prostatectomy specimens were selected from the archives of the Department of Pathology, University of Innsbruck. These consisted of 67 cases of benign prostatic hyperplasia (BPH) and 173 cases of prostatic adenocarcinoma (PAC). The specimen collection was divided randomly into a training set and test set. Cytospin preparations of disaggregated cells prepared from paraffin-embedded material were stained specifically for DNA by the Feulgen method. For the cancer cases, only tissue that histologically appeared nonmalignant, from the vicinity of the lesion, was used in the sample preparation. Only normal-appearing diploid cell nuclei were analyzed from both the BPH and PAC groups. A discriminator comprised of three nuclear texture features to separate BPH from PAC cases was derived from the training set of cases, and then applied to the independent test set cases. RESULTS: PAC cases were separated from BPH cases with a sensitivity of 90% and a specificity of 97% on the independent test set of cases. CONCLUSIONS: This retrospective investigation demonstrates that by high-resolution image cytometry it is possible to detect the presence of prostatic adenocarcinoma with very high reliability when examining prostate samples that only contain histologically normal-looking cells. This method could become clinically relevant in identification of cancers missed by histologically negative core needle biopsies.