Papillary thyroid carcinoma tall cell variant shares accumulation of mitochondria, mitochondrial DNA mutations, and loss of oxidative phosphorylation complex I integrity with oncocytic tumors.

Papillary thyroid carcinoma tall cell variant (PTC-TCV), a form of PTC regarded as an aggressive subtype, shares several morphologic features with oncocytic tumors. Pathogenic homoplasmic/highly heteroplasmic somatic mitochondrial DNA (mtDNA) mutations, usually affecting oxidative phosphorylation (OXPHOS) complex I subunits, are hallmarks of oncocytic cells. To clarify the relationship between PTC-TCV and oncocytic thyroid tumors, 17 PTC-TCV and 16 PTC non-TCV controls (cPTC) were subjected to: (1) transmission electron microscopy (TEM) to assess mitochondria accumulation, (2) next-generation sequencing to analyze mtDNA and nuclear genes frequently mutated in thyroid carcinoma, and (3) immunohistochemistry (IHC) for prohibitin and complex I subunit NDUFS4 to evaluate OXPHOS integrity. TEM showed replacement of cytoplasm by mitochondria in PTC-TCV but not in cPTC cells. All 17 PTC-TCV had at least one mtDNA mutation, totaling 21 mutations; 3/16 cPTC (19%) had mtDNA mutations (p < 0.001). PTC-TCV mtDNA mutations were homoplasmic/highly heteroplasmic, 16/21 (76%) mapping within mtDNA-encoded complex I subunits. MtDNA mutations in cPTC were homoplasmic in 2 cases and at low heteroplasmy in the third case, 2/3 mapping to mtDNA-encoded complex I subunits; 2/3 cPTC with mtDNA mutations had small tall cell subpopulations. PTC-TCV showed strong prohibitin expression and cPTC low-level expression, consistent with massive and limited mitochondrial content, respectively. All 17 PTC-TCV showed NDUFS4 loss (partial or complete) and 3 of 16 cPTC (19%) had (partial) NDUFS4 loss, consistent with lack of complex I integrity in PTC-TCV (p < 0.001). IHC loss of NDUFS4 was associated with mtDNA mutations (p < 0.001). Four BRAF V600E mutated PTCs had loss of NDUSF4 expression limited to neoplastic cell subpopulations with tall cell features, indicating that PTCs first acquire BRAF V600E and then mtDNA mutations. Similar to oncocytic thyroid tumors, PTC-TCV is characterized by mtDNA mutations, massive accumulation of mitochondria, and loss of OXPHOS integrity. IHC loss of NDUFS-4 can be used as a surrogate marker for OXPHOS disruption and to reliably diagnose PTC-TCV.

Total resection of a giant retroperitoneal and mediastinal ganglioneuroma-case report and systematic review of the literature.

BACKGROUND: Ganglioneuromas (GNs) are extremely rare, slowly growing, benign tumors that can arise from Schwann cells, ganglion cells, and neuronal or fibrous tissues. Due to their origin from the sympathetic neural crest, they show neuroendocrine potential; however, most are reported to be hormonally inactive. Nevertheless, complete surgical removal is recommended for symptom control or for the prevention of potential malignant degeneration. CASE REPORT: A 30-year-old female was referred to our oncologic center due to a giant retroperitoneal and mediastinal mass detected in computed tomography (CT) scans. The initial symptoms were transient nausea, diarrhea, and crampy abdominal pain. There was a positive family history including 5 first- and second-degree relatives. Presurgical biopsy revealed a benign ganglioneuroma. Total resection (TR) of a 35 × 25 × 25 cm, 2550-g tumor was obtained successfully via laparotomy combined with thoracotomy and partial incision of the diaphragm. Histopathological analysis confirmed the diagnosis. Surgically challenging aspects were the bilateral tumor invasion from the retroperitoneum into the mediastinum through the aortic hiatus with the need of a bilateral 2-cavity procedure, as well as the tumor-related displacement of the abdominal aorta, the mesenteric vessels, and the inferior vena cava. Due to their anatomic course through the tumor mass, the lumbar aortic vessels needed to be partially resected. Postoperative functioning was excellent without any sign of neurologic deficit. CONCLUSION: Here, we present the largest case of a TR of a GN with retroperitoneal and mediastinal expansion. On review of the literature, this is the largest reported GN resected and was performed safely. Additionally, we present the first systematic literature review for large GN (> 10 cm) as well as for resected tumors growing from the abdominal cavity into the thoracic cavity.

Clinically high-risk breast cancer displays markedly discordant molecular risk predictions between the MammaPrint and EndoPredict tests.

Inter-test concordance between the MammaPrint and the EndoPredict tests used to predict the risk of recurrence in breast cancer was evaluated in 94 oestrogen receptor-positive, HER2-negative breast cancers. We correlated histopathological data with clinical risk estimation as defined in the MINDACT trial. 42.6% (40/94) of cases were high-risk by MammaPrint, 44.7% (42/94) by EndoPredict (EPclin), and 45.7% (43/94) by clinical risk definition. Thirty-six percent of genomic risk predictions were discordant with a low inter-test correlation between EndoPredict and MammaPrint (p = 0.012; κ = 0.27, 95% CI [0.069, 0.46]). Clinical risk stratification did not correlate with MammaPrint (p = 0.476) but highly correlated with EndoPredict (p < 0.001). Consequently, clinically high-risk tumours (n = 43) were more frequently high-risk by EndoPredict than by MammaPrint (76.6% vs. 46.5%, p = 0.004), with 44% of cases discordantly classified and no significant association between genomic risk predictions (p = 0.294). Clinicians need to be aware that clinical pre-stratification can profoundly influence multigenomic test performance.

18F-Fluorocholine PET/CT in the assessment of primary hyperparathyroidism compared with 99mTc-MIBI or 99mTc-tetrofosmin SPECT/CT: a prospective dual-centre study in 100 patients.

PURPOSE: In this prospective study we compared the accuracy of 18F-fluorocholine PET/CT with that of 99mTc-MIBI or99mTc-tetrofosmin SPECT/CT in the preoperative detection of parathyroid adenoma in patients with primary hyperparathyroidism. We also assessed the value of semiquantitative parameters in differentiating between parathyroid hyperplasia and adenoma. METHODS: Both 18F-fluorocholine PET/CT and 99mTc-MIBI/tetrofosmin SPECT/CT were performed in 100 consecutive patients with biochemical evidence of primary hyperparathyroidism. At least one abnormal focus on either 18F-fluorocholine or 99mTc-MIBI/tetrofosmin corresponding to a parathyroid gland or ectopic parathyroid tissue was considered as a positive finding. In 76 patients with positive findings on at least one imaging modality, surgical exploration was performed within 6 months, and the results were related to histopathological findings and clinical and laboratory findings at 3-6 months as the standard of truth. In 24 patients, no surgery was performed: in 18 patients with positive imaging findings surgery was refused or considered risky, and in 6 patients imaging was negative. Therefore, data from 82 patients (76 undergoing surgery, 6 without surgery) in whom the standard of truth criteria were met, were used in the final analysis. RESULTS: All patients showed biochemical evidence of primary hyperparathyroidism with a mean serum calcium level of 2.78 ± 0.34 mmol/l and parathormone (PTH) level of 196.5 ± 236.4 pg/ml. The study results in 76 patients with verified histopathology and 3 patients with negative imaging findings were analysed. Three of six patients with negative imaging showed normalized serum PTH and calcium levels on laboratory follow-up at 3 and 6 months, and the results were considered true negative. In a patient-based analysis, the detection rate with 18F-fluorocholine PET/CT was 93% (76/82), but was only 61% (50/82) with 99mTc-MIBI/tetrofosmin SPECT/CT. In a lesion-based analysis, the sensitivity, specificity, positive predictive value, negative predictive value and overall accuracy of 18F-fluorocholine PET/CT in the detection of parathyroid adenoma were 93.7%, 96.0%, 90.2%, 97.4% and 95.3%, respectively, and of 99mTc-MIBI/tetrofosmin SPECT/CT were 60.8%, 98.5%, 94.1%, 86.3% and 87.7%, respectively. Although 18F-fluorocholine PET-positive adenomatous lesions showed higher SUVmax values than the hyperplastic glands (6.80 ± 3.78 vs. 4.53 ± 0.40) in the semiquantitative analysis, the difference was not significant (p = 0.236). The mean size (measured as the length of the greatest dimension) and weight of adenomas were 15.9 ± 7.6 mm (median 15 mm, range 1-40 mm) and 1.71 ± 1.86 g (median 1 g, range: 0.25-9 g), respectively. Among the analysed parameters including serum calcium and PTH and the size and weight of parathyroid adenomas, size was significantly different between patients with negative 99mTc-MIBI/tetrofosmin SPECT/CT and those with positive 99mTc-MIBI/tetrofosmin SPECT/CT (mean size 13.4 ± 7.6 mm vs. 16.9 ± 7.4 mm, respectively; p = 0.042). CONCLUSION: In this prospective study, 18F-fluorocholine PET/CT showed promise as a functional imaging modality, being clearly superior to 99mTc-MIBI/tetrofosmin SPECT/CT, especially in the detection and localization of small parathyroid adenomas in patients with primary hyperparathyroidism. SUVmax was higher in parathyroid adenomas than in hyperplasia. However, further evaluation of this modality is needed.

Genetic profiling of putative breast cancer stem cells from malignant pleural effusions.

A common symptom during late stage breast cancer disease is pleural effusion, which is related to poor prognosis. Malignant cells can be detected in pleural effusions indicating metastatic spread from the primary tumor site. Pleural effusions have been shown to be a useful source for studying metastasis and for isolating cells with putative cancer stem cell (CSC) properties. For the present study, pleural effusion aspirates from 17 metastatic breast cancer patients were processed to propagate CSCs in vitro. Patient-derived aspirates were cultured under sphere forming conditions and isolated primary cultures were further sorted for cancer stem cell subpopulations ALDH1+ and CD44+CD24-/low. Additionally, sphere forming efficiency of CSC and non-CSC subpopulations was determined. In order to genetically characterize the different tumor subpopulations, DNA was isolated from pleural effusions before and after cell sorting, and compared with corresponding DNA copy number profiles from primary tumors or bone metastasis using low-coverage whole genome sequencing (SCNA-seq). In general, unsorted cells had a higher potential to form spheres when compared to CSC subpopulations. In most cases, cell sorting did not yield sufficient cells for copy number analysis. A total of five from nine analyzed unsorted pleura samples (55%) showed aberrant copy number profiles similar to the respective primary tumor. However, most sorted subpopulations showed a balanced profile indicating an insufficient amount of tumor cells and low sensitivity of the sequencing method. Finally, we were able to establish a long term cell culture from one pleural effusion sample, which was characterized in detail. In conclusion, we confirm that pleural effusions are a suitable source for enrichment of putative CSC. However, sequencing based molecular characterization is impeded due to insufficient sensitivity along with a high number of normal contaminating cells, which are masking genetic alterations of rare cancer (stem) cells.

Disseminated Histoplasmosis: A Challenging Differential Diagnostic Consideration for Suspected Malignant Lesions in the Digestive Tract.

Histoplasmosis is well characterized as an endemic fungal disease restricted to certain areas of the USA. In Middle Europe, most patients present with acute pulmonary symptoms after travelling to endemic areas. Here, we want to illustrate the case of a 67-year-old man who presented with persistent oral ulcers, hoarseness, dysphagia, diarrhea, and weight loss to our Department of Otorhinolaryngology in December 2014. He was a retired construction worker and had a history of soil-disruptive activities in Africa and Middle and South America during employment. A positron emission tomography-computed tomography scan revealed prominent hypermetabolic lesions in the cecum and the lung, pointing towards a malignant disease. Surprisingly, histological examination of colonic and oral biopsies revealed abundant intracellular fungal elements, highly suspicious of Histoplasma capsulatum. Diagnosis was finally confirmed by panfungal polymerase chain reaction. Upon treatment with liposomal amphotericin followed by itraconazole, the severely ill patient showed an impressive clinical response. This case describes a disseminated manifestation of H. capsulatum years after the first exposure in an otherwise immunocompetent patient descending from a nonendemic area.

Clear-cell differentiation and lymphatic invasion, but not the revised TNM classification, predict lymph node metastases in pT1 penile cancer: a clinicopathologic study of 76 patients from a low incidence area.

OBJECTIVE: Prediction of lymph node (LN) metastases in penile invasive cancer relies on clinical features and histologic characteristics of the primary tumor. Correct prediction, however, is difficult, as only 50% patients undergoing lymphadenectomies will have LN metastases. In 2009, the tumor, nodes, metastases (TNM) classification for staging of early penile cancers was revised. We tested the predictive accuracy of the revised TNM classification in a low incidence area for penile carcinoma. MATERIALS AND METHODS: The presence of LN metastases in 76 men with pT1 penile cancers was correlated with the 2009 TNM subclassification, which is based on a combined evaluation of tumor grade and lymphatic invasion, but also with individual parameters, such as histologic grade, lymphatic invasion, perineural invasion, invasion depth, growth pattern and human papilloma virus (HPV) status. RESULTS: 76pT1 penile cancers were reclassified into 31pT1a squamous cell carcinomas (SCC) and 45pT1b (41 SCC; 4 clear-cell carcinomas); 12/22 men (55%; 8 SCC, 4 clear-cell carcinomas) undergoing lymphadenectomy for enlarged inguinal lymph nodes had metastases, 54 patients without enlarged LN and lymphadenectomies had no LN metastases during follow-up of median 47 months. Statistically, clear cell differentiation of the primary carcinoma was highly associated with metastases (100% clear-cell carcinomas vs. 11% SCC) and poor survival (50% vs. 5.5%). Among conventional SCC, only lymphatic invasion showed a highly significant association with metastases with 100% specificity. The 2009 TNM classification, tumor grade alone, perineural invasion, growth pattern, invasion depth or HPV status could not predict LN status. Lymphadenectomy for enlarged LN resulted in 100% sensitivity and 42% predictive probability for identifying metastases and a 16% false positive rate. Statistically, survival correlated significantly with clear-cell differentiation and with lymphatic invasion in both clear-cell carcinomas and conventional SCC. CONCLUSIONS: Penile clear-cell carcinomas are more aggressive cancers than SCC. Our observation suggests a benefit of a prophylactic lymphadenectomy for patients with clear-cell carcinomas. Among conventional SCC, only lymphatic invasion predicted LN metastases. Neither tumor grade alone nor perineural invasion, growth pattern, depth of invasion, and subgrouping according to the revised TNM classification correlated with metastases. Clinical evaluation of the LN status was superior to histologic risk stratification.

Genetic background effects of keratin 8 and 18 in a DDC-induced hepatotoxicity and Mallory-Denk body formation mouse model.

Keratin 8 (K8) and keratin 18 (K18) form the major hepatocyte cytoskeleton. We investigated the impact of genetic loss of either K8 or K18 on liver homeostasis under toxic stress with the hypothesis that K8 and K18 exert different functions. krt8⁻/⁻ and krt18⁻/⁻ mice crossed into the same 129-ola genetic background were treated by acute and chronic administration of 3,5-diethoxy-carbonyl-1,4-dihydrocollidine (DDC). In acutely DDC-intoxicated mice, macrovesicular steatosis was more pronounced in krt8⁻/⁻ and krt18⁻/⁻ compared with wild-type (wt) animals. Mallory-Denk bodies (MDBs) appeared in krt18⁻/⁻ mice already at an early stage of intoxication in contrast to krt8⁻/⁻ mice that did not display MDB formation when fed with DDC. Keratin-deficient mice displayed significantly lower numbers of apoptotic hepatocytes than wt animals. krt8⁻/⁻, krt18⁻/⁻ and control mice displayed comparable cell proliferation rates. Chronically DDC-intoxicated krt18⁻/⁻ and wt mice showed a similarly increased degree of steatohepatitis with hepatocyte ballooning and MDB formation. In krt8⁻/⁻ mice, steatosis was less, ballooning, and MDBs were absent. krt18⁻/⁻ mice developed MDBs whereas krt8⁻/⁻ mice on the same genetic background did not, highlighting the significance of different structural properties of keratins. They are independent of the genetic background as an intrinsic factor. By contrast, toxicity effects may depend on the genetic background. krt8⁻/⁻ and krt18⁻/⁻ mice on the same genetic background show similar sensitivity to DDC intoxication and almost resemble wt animals regarding survival, degree of porphyria, liver-to-body weight ratio, serum bilirubin and liver enzyme levels. This stands in contrast to previous work where krt8⁻/⁻ and krt18⁻/⁻ mice on different genetic backgrounds were investigated.

Microcystic/reticular schwannoma of the pancreas: a potential diagnostic pitfall.

Schwannomas occurring in the pancreatic head are rare benign non-recurring mesenchymal neoplasms and are reported to show classic morphologic features. Herein we report a case of a 62 year old male presenting with a 5 cm mass in the pancreatic head encasing the portal vein and the truncus coeliacus. Preoperative fine needle aspiration revealed malignant tumour cells consistent with a moderately differentiated adenocarcinoma. A Whipple surgery was performed after palliative chemotherapy. Histological evaluation revealed a multinodular unencapsulated tumour with focal infiltration into pancreas parenchyma and a striking microcystic/reticular growth pattern. Anastomosing and intersecting strands of spindle cells with eosinophilic cytoplasm set in a myxoid partly collagenous stroma were observed. The tumour cell nuclei were round oval and tapered and showed inconspicuous small nucleoli. Degenerative nuclear atypia was seen. Mitotic activity was sparse (1/50 HPF). Pleomorphism or necrosis was absent. The tumour cells showed strong nuclear and cytoplasmic positivity for S-100 protein, and focal positivity for glial fibrillary acidic protein. The diagnosis of a microcystic/reticular schwannoma was made. The awareness of and, to some extent, the knowledge about this rare tumour are needed to achieve the correct diagnosis and to avoid confusion, especially with malignant pancreatic neoplasms.

Androgen receptor expression in breast cancer patients tested for BRCA1 and BRCA2 mutations.

AIM: To assess the expression of receptors for androgen (AR), oestrogen (ER) and progesterone (PR) as well as human epidermal growth factor receptor type 2 (Her-2/neu) status of breast carcinomas in breast cancer susceptibility gene (BRCA) BRCA1/2 mutation carriers and BRCA1/2 negative tested women. METHODS: One hundred and thirty-five breast cancers in women tested for BRCA1/2 mutations. Screening for BRCA1 and BRCA2 mutations was performed by direct sequencing of all BRCA1 and BRCA2 exons as well as the surrounding intronic sequences. Additionally, BRCA genes were analysed with multiplex ligation-dependent probe amplification. Consecutive paraffin sections were examined immunohistochemically for AR, ER, PR and Her-2/neu. RESULTS: Of the 135 tumours, 43 (32%) were BRCA1-related, 18 (13%) were BRCA2-related and 74 (55%) were BRCA1/2-negative. Seventy-two per cent of the BRCA1-related, 22% of the BRCA2-related and 12% of the BRCA1/2-negative tumours were triple (ER, PR, Her2neu)-negative. Eighty-four per cent of BRCA1 mutated cancers were high-grade (G3) tumours. ARs were expressed in 30% (13 of 43) of BRCA1-related, in 78% (14 of 18) in BRCA2-related tumours and in 76% (56 of 74) in BRCA1/2 negative tumours. Twenty-one per cent of ER-negative BRCA1-related tumours expressed androgen receptors. CONCLUSION: Approximately one in five BRCA1 mutated breast cancers negative for ER and PR express androgen receptors. Modulation of AR might open a new avenue for treating these high-risk cancers.

The role of osteopontin and tumor necrosis factor alpha receptor-1 in xenobiotic-induced cholangitis and biliary fibrosis in mice.

Proinflammatory and profibrotic cytokines such as osteopontin (OPN) and tumor necrosis factor-alpha receptor-1 (TNFR(1)) may be critically involved in the pathogenesis of cholangiopathies and biliary fibrosis. We therefore aimed to determine the role of genetic loss of either OPN or TNFR(1) in 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC)-fed mice as a model of xenobiotic-induced sclerosing cholangitis with biliary-type liver fibrosis using respective knock-out mice. OPN and TNFR(1) knock-out mice were fed a 0.1% DDC-supplemented diet for 4 weeks and compared with corresponding wild-type (WT) controls. Liver morphology (H&E staining), serum markers of liver injury and cholestasis (ALT, AP, bilirubin), markers of inflammation in liver (CD11b and F4/80 immunostaining, mRNA expression of iNOS, MCP-1, IL-1beta, INF-gamma, TNF-alpha and OPN), degree of ductular reaction (immunohistochemistry with morphometric analysis and western blotting for cholangiocyte-specific marker keratin 19) and degree of liver fibrosis (Sirius-red staining, hepatic hydroxyproline content for quantification) were compared between groups. DDC feeding in OPN and TNFR(1) knock-out mice and respective WT controls resulted in comparable extent of liver injury, inflammatory response, ductular reaction and liver fibrosis. Our data indicate that genetic loss of neither OPN nor TNFR(1) significantly effects on the pathogenesis of DDC-induced sclerosing cholangitis, ductular reaction and resulting biliary fibrosis.

Oncocytic versus mitochondrion-rich follicular thyroid tumours: should we make a difference?

AIMS: To separate true oncocytic neoplasms from mitochondrion-rich non-oncocytic lesions based on the intracellular relationship between major cell organelles, and to establish the diagnostic and clinical relevance of this distinction. METHODS AND RESULTS: Tissue samples from 276 follicular adenomas, 194 follicular carcinomas, 162 normal thyroids and 296 non-neoplastic lesions were classified as conventional, mitochondrion-rich or oncocytic based on the immunohistochemically assessed quantity and intracellular distribution of mitochondria and endoplasmic reticulum (ER) and nuclear position. Pathological and clinical features were compared among the groups. In oncocytes, densely packed mitochondria resulted in homogeneous immunolabelling of basal cytoplasmic regions, whereas ER and the nuclei were typically displaced to the apical position. This aberrant organelle distribution was not observed in non-oncocytes, which allowed reliable distinction between oncocytic and mitochondrion-rich lesions. Clinically, mitochondrial increase in non-oncocytic lesions was associated with neoplasia, malignancy and higher cancer recurrence rates. Similar correlation, albeit less pronounced, was observed within the oncocytic tumour group. By contrast, oncocytic change per se was not associated with neoplasia, malignancy or cancer aggressiveness. CONCLUSIONS: True oncocytic neoplasms can be distinguished from mitochondrion-rich non-oncocytic tumours based on aberrant distribution of all major cell organelles. This distinction has immediate clinical relevance and should be implemented in practice.

Farnesoid X receptor critically determines the fibrotic response in mice but is expressed to a low extent in human hepatic stellate cells and periductal myofibroblasts.

The nuclear bile acid receptor, farnesoid X receptor (FXR), may play a pivotal role in liver fibrosis. We tested the impact of genetic FXR ablation in four different mouse models. Hepatic fibrosis was induced in wild-type and FXR knock-out mice (FXR(-/-)) by CCl(4) intoxication, 3,5-diethoxycarbonyl-1,4-dihydrocollidine feeding, common bile duct ligation, or Schistosoma mansoni (S.m.)-infection. In addition, we determined nuclear receptor expression levels (FXR, pregnane X receptor (PXR), vitamin D receptor, constitutive androstane receptor (CAR), small heterodimer partner (SHP)) in mouse hepatic stellate cells (HSCs), portal myofibroblasts (MFBs), and human HSCs. Cell type-specific FXR protein expression was determined by immunohistochemistry in five mouse models and prototypic human fibrotic liver diseases. Expression of nuclear receptors was much lower in mouse and human HSCs/MFBs compared with total liver expression with the exception of vitamin D receptor. FXR protein was undetectable in mouse and human HSCs and MFBs. FXR loss had no effect in CCl(4)-intoxicated and S.m.-infected mice, but significantly decreased liver fibrosis of the biliary type (common bile duct ligation, 3,5-diethoxycarbonyl-1,4-dihydrocollidine). These data suggest that FXR loss significantly reduces fibrosis of the biliary type, but has no impact on non-cholestatic liver fibrosis. Since there is no FXR expression in HSCs and MFBs in liver fibrosis, our data indicate that these cells may not represent direct therapeutic targets for FXR ligands.

Diagnostic yield of touch imprint cytology of prostate core needle biopsies.

Touch imprint cytology may provide additional information to core needle biopsy interpretation according to previous reports. The aim of this study was to investigate the diagnostic yield of this method in the diagnosis of prostate carcinoma. For this purpose, 452 transrectal prostate needle biopsies were evaluated from 56 patients. All patients were clinically suspicious of having prostate carcinoma. Two touch imprints were prepared from each fresh biopsy cylinder. Results of the standard histology and of the touch imprint evaluation were compared. Histologically negative biopsy cylinders were further evaluated for prostate carcinoma by fine step serial sectioning. The standard histological examination showed adenocarcinoma in 27 patients. Touch imprint cytology revealed atypical cells suspicious of carcinoma in 38 patients. This group included all 27 patients with positive standard histology and further 11 patients with initially negative core biopsy. Following serial sectioning, in three out of these 11 samples, histological evidence of a carcinoma could be proven. Fine step serial sectioning of all 29 core biopsies negative for carcinoma by standard histological examination, 26 patients remained negative. All three core biopsies initially negative by standard histology but positive after serial sectioning had cytology findings suspicious of carcinoma. We conclude, that in problematic cases the additional use of touch imprint cytology and serial sectioning of prostate core needle biopsies significantly improve the diagnostic accuracy.