Chest examinations in children with real-time magnetic resonance imaging: first clinical experience.

BACKGROUND: Real-time magnetic resonance imaging (MRI) based on a fast low-angle shot technique 2.0 (FLASH 2.0) is highly effective against artifacts caused due to the bulk and pulmonary and cardiac motions of the patient. However, to date, there are no reports on the application of this innovative technique to pediatric lung MRI. OBJECTIVE: This study aimed to identify the limits of resolution and image quality of real-time lung MRI in children and to assess the types and minimal size of lesions with these new sequences. MATERIALS AND METHODS: In this retrospective study, pathological lung findings in 87 children were classified into 6 subgroups, as detected on conventional MRI: metastases and tumors, consolidation, scars, hyperinflation, interstitial pathology and bronchiectasis. Subsequently, the findings were grouped according to size (4-6 mm, 7-9 mm and ≥ 10 mm) and evaluated for visual delineation of the findings (0 = not visible, 1 = hardly visible and 2 = well visualized). RESULTS: Real-time MRI allows for diagnostic, artifact-free thorax images to be obtained, regardless of patient movements. The delineation of findings strongly correlates with the size of the pathology. Metastases, consolidation and scars were visible at 100% when larger than 9 mm. In the 7-9 mm subgroup, the visibility was 83% for metastases, 88% for consolidation and 100% for scars in T2/T1 weighting. Though often visible, smaller pathological lesions of 4-6 mm in size did not regularly meet the expected diagnostic confidence: The visibility of metastases was 18%, consolidation was 64% and scars was 71%. Diffuse interstitial lung changes and hyperinflation, known as "MR-minus pathologies," were not accessible to real-time MRI. CONCLUSION: The method provides motion robust images of the lung and thorax. However, the lower sensitivity for small lung lesions is a major limitation for routine use of this technique. Currently, the method is adequate for diagnosing inflammatory lung diseases, atelectasis, effusions and lung scarring in children with irregular breathing patterns or bulk motion on sedation-free MRI. A medium-term goal is to improve the diagnostic accuracy of small nodules and interstitial lesions.

Hydrocephalus in aqueductal stenosis--a retrospective outcome analysis and proposal of subtype classification.

UNLABELLED: Treatment of aqueductal stenosis (AQS) has undergone several paradigm shifts during the past decades. Currently, endoscopic ventriculostomy (ETV) is recommended as treatment of choice. Several authors have addressed the issue of variable ETV success rates depending on age and pathogenetic factors. However, success rates have usually been defined as "ETV non-failure." The aim of the study was a retrospective analysis of radiological and neurological treatment response after ETV or VP-shunting (VPS) in age-dependent subtypes of AQS. PATIENTS AND METHODS: Eighty patients (median age 12.0 years, range 0-79 years) have been treated for MRI-proven aqueductal stenosis. Neurological treatment success was defined by neurological improvement and, in childhood, head circumference. Radiological response was measured as Evan's index in follow-up MRI. Initial signs and symptoms, type of surgery, and complications were analyzed. RESULTS: Four types of AQS have been defined with distinct age ranges and symptomatology: congenital type I (n = 24), chronic progressive (tectal tumor-like) type II (n = 23), acute type III (n = 10), and adult chronic (normal-pressure hydrocephalus-like) type IV (n = 23). Retrospective analysis of neurological and radiological outcome suggested that congenital type I (<1 years of age) may be more successfully treated with VPS than with ETV (81 vs. 50 %). Treatment of chronic juvenile type II (age 2-15) by ETV 19 % compared to 57 % after VP-shunt, but similar neurological improvement (>80 %). There has been no influence of persistent ventriculomegaly in type II after ETV in contrast to VPS therapy for neurological outcome. Adult acute type III (age > 15 years) responded excellent to ETV. Chronic type IV (iNPH-like) patients (age > 21) responded neurologically in 70 % after ETV and VPS, but radiological response was low (5 %). CONCLUSION: AQS can be divided into four distinct age groups and types in regards of clinical course and symptomatology. Depending on the AQS type, ETV cannot be unequivocally recommended. Congenital type I AQS may have a better neurological outcome with VP-shunt whereas acute type III offers excellent ETV results. Chronic progressive type II still requires prospective investigation of long-term ETV outcome, especially when ventriculomegaly persists. Late chronic type IV seems to result in similar outcome after VP-shunt and ETV.

Cerebrospinal Fluid Protein Concentrations in Hydrocephalus.

CSF protein levels are altered in neurological disorders, such as hydrocephalus of different etiologies. In this retrospective observational study, we analyzed cerebrospinal fluid (CSF) samples in hydrocephalic diseases such as aqueductal stenosis (AQS, n = 27), normal pressure hydrocephalus (NPH, n = 24), hydrocephalus communicans (commHC, n = 25) and idiopathic intracranial hypertension (IIH)/pseudotumor cerebri (PC, n = 7) in comparison with neurological patients without hydrocephalic configuration (control, n = 95). CSF was obtained through CSF diversion procedures and lumbar punction and analyzed for protein concentrations according to the institution's laboratory standards. We found significantly decreased CSF protein levels in patients suffering from AQS (0.13 mg/dL [0.1-0.16 mg/dL] p = 2.28 × 10-8) and from PC (0.18 mg/dL [0.12-0.24 mg/dL] p = 0.01) compared with controls (0.34 mg/dL [0.33-0.35 mg/dL]). Protein levels were not altered in patients suffering from commHC and NPH compared with neurologically healthy individuals. We propose that a decrease in CSF protein levels is part of an active counterregulatory mechanism to lower CSF volume and, subsequently, intracranial pressure in specific diseases. Research regarding said mechanism and more specific proteomic research on a cellular level must still be performed to prove this hypothesis. Differences in protein levels between different diseases point to different etiologies and mechanisms in different hydrocephalic pathologies.

Laparoscopic versus robot-assisted Nissen fundoplication in an infant pig model.

PURPOSE: Surgical robots are designed to facilitate dissection and suturing, although objective data on their superiority are lacking. This study compares conventional laparoscopic Nissen fundoplication (CLNF) to robot-assisted Nissen fundoplication (RANF) using computer-based workflow analysis in an infant pig model. METHODS: CLNF and RANF were performed in 12 pigs. Surgical workflow was segmented into phases. Time required to perform specific actions was compared by t test. The quality of knot-tying was evaluated by a skill scoring system. Cardia yield pressure (CYP) was determined to test the efficacy of the fundoplications, and the incidence of complications was compared. RESULTS: There was no difference in average times to complete the various phases, despite faster robotic knot-tying (p = 0.001). Suturing quality was superior in CLNF (p = 0.02). CYP increased similarly in both groups. Workflow-interrupting hemorrhage and pneumothorax occurred more frequently during CLNF (p = 0.040 and 0.044, respectively), while more sutures broke during RANF (p = 0.001). CONCLUSION: The robot provides no clear temporal advantage compared to conventional laparoscopy for fundoplication, although suturing was faster in RANF. Fewer complications were noted using the robot. RANF and CLNF were equally efficient anti-reflux procedures. For robotic surgery to manifest its full potential, more complex operations may have to be evaluated.

Resection of an Extraovarian Noniuteinized Thecoma in a 14-Year-Old Girl.

Thecomas are rare benign sex cord-stromal tumors that account for less than 1% of all ovarian tumors. They usually affect postmenopausal women and become symptomatic with abnormal bleeding. In adolescents, less than 10 cases have been reported so far, mainly with symptoms of hormonal disbalance. Extraovarian thecomas represent an even rarer entity, with only two cases described so far, none of them in the pediatric population. We report the case of a 14-year-old girl who presented with sudden-onset abdominal pain, dysuria, and fever, as well as highly elevated serum inflammation parameters. Ultrasound and magnetic resonance imaging (MRI) revealed a large, inhomogeneous pelvic mass (16 cm × 9 cm × 13 cm) with indistinct margins, suggestive of an infiltrative malignant teratoma or sarcoma. Laparoscopy confirmed a large mass of unknown origin. In contrast to the infiltrative character seen on preoperative MRI, the tumor could be easily exteriorized and resected after conversion to laparotomy. Ovaries, fallopian tubes, and uterus remained unaffected. Histopathology revealed a benign nonluteinized thecoma. The postoperative course and 19-month follow-up were uneventful.

Residual lymph node metastasis in stage 4 neuroblastoma--advantage of radio-guided surgery?

Log-term prognosis of children suffering from high-risk neuroblastomas is characterized by a shortened event-free survival, especially if metastases remain after chemotherapy. We report the case of a 3-year-old boy afflicted with a stage 4 neuroblastoma and persistent residual lymph node metastases despite the administration of a various number of treatment modalities. The insertion of a MIBG (metaiodobenzylguanidine) single-photon emission computed tomography (SPECT)-CT and radio-guided surgery implementing a hand held gamma probe finally allowed the exact localization and resection of the suspected lymphatic tissue. As a consequence, the child has been under event-free remission for 20 months. Because study-based knowledge is missing due to the small number of affected patients, individual case reports are helpful to improve future treatment strategies.

Treatment of Ruptured Giant Omphalocele and Gastroschisis with Liver Herniation using a Wound Retractor as a Novel Approach.

Ruptured giant omphaloceles (GO) and gastroschisis with total liver herniation are rare cases of exceptionally large abdominal wall defects. Many of these children have lethal outcome. The surgical and postsurgical management are complex. We report on two cases treated with staged surgical repair using a wound retractor as a silo. With this technique, the liver and intestines could be reduced into the abdomen with secondary closure of the abdominal cavity within the first 1 to 2 weeks of life.

Workflow analysis of laparoscopic Nissen fundoplication in infant pigs- a model for surgical feedback and training.

BACKGROUND: Many fields use workflow analysis to assess and improve performance of complex tasks. In pediatric endosurgery, workflow analysis may help optimize operative planning and motor skills by breaking down the procedure into particular phases, evaluating these steps individually, and supplying feedback to the surgeon. OBJECTIVE: To develop a module of computer-based surgical workflow analysis for laparoscopic Nissen fundoplication(LNF) and to evaluate its applicability in an infant pig model. METHODS: LNF was performed in 12 pigs (weight, 7-10 kg) by a single surgeon. Based on synchronized intra and extracorporal movie recordings, the surgical workflow was segmented into temporal operative phases(preparation, dissection, reconstruction and conclusion). During each stage, all actions were recorded in a virtual timeline using a customized workflow editor. Specific tasks, such as knot-tying, were evaluated in detail.Time necessary to perform these actions was compared throughout the study. RESULTS: While time required for the preparation decreased by more than 70% from 4577 to 1379 seconds,and the dissection phase decreased from 2359 to 399 seconds (pig 1 and 12, respectively), the other two phases remained relatively stable. Mean time to perform the entire suture and a 5-throw knot remained constant as well. CONCLUSION: Our workflow analysis model allows the quantitative evaluation of dynamic actions related to LNF.This data can be used to define average benchmark criteria for the procedures that comprise this operation. It thereby permits task-oriented refinement of surgical technique as well as monitoring the efficacy of training.Although preoperative preparation time decreased substantially, and dissection became faster, time required for the reconstruction and conclusion phases remained relatively constant for a surgeon with moderate experience.Likewise, knot-tying did not accelerate in this setting.S-117

CHL1 and NrCAM are Primarily Expressed in Low Grade Pediatric Neuroblastoma.

BACKGROUND: Neural cell adhesion molecules like close homolog of L1 protein (CHL1) and neuronal glia related cell adhesion molecule (NrCAM) play an important role in development and regeneration of the central nervous system. However, they are also associated with cancerogenesis and progression in adult malignancies, thus gain increasing importance in cancer research. We therefore studied the expression of CHL1 and NrCAM according to the course of disease in children with neuroblastoma. METHODS: CHL1 and NrCAM expression levels were histologically assessed by tissue microarrays from surgically resected neuroblastoma specimens of 56 children. Expression of both markers was correlated to demographics as well as clinical data including metastatic dissemination and survival. RESULTS: CHL1 was expressed in 9% and NrCAM in 51% of neuroblastoma tissue samples. Expression of CHL1 was higher in patients with low Hughes grade 1a/b (p=0.01). NrCAM was more often detected in patients with a low International Staging System (INSS) score 1/2 (p=0.04). CONCLUSION: CHL1 and NrCAM expression was associated with low-grade pediatric neuroblastoma. These adhesion molecules may play a role in early tumor development of neuroblastoma.

Cardia yield pressure measurement in an infant porcine model: a novel technique to evaluate the quality of laparoscopic fundoplication.

BACKGROUND: Cardia yield pressure (CYP) has been described as a measure of the combined effect of all antireflux mechanisms and not simply as another test of lower esophageal sphincter pressure. In this paper, we present a simple technique for the measurement of CYP before and after fundoplication through laparoscopic gastrostomy in an experimental pig model. MATERIALS AND METHODS: Twelve 8-week-old female pigs with a mean weight of 8.7 +/- 0.7 kg underwent laparoscopic gastrostomy placement and Nissen fundoplication under general anesthesia. CYP was determined before and after the fundoplication by filling the stomach with water until reaching the pressure at which the cardia opened and became incompetent. Pre- and postoperative CYP was compared by using the Student's t-test for paired samples. RESULTS: Laparoscopic Nissen fundoplication and gastrostomy was completed in all pigs. CYP increased in all subjects after fundoplication, from a mean of 20 +/- 8 to a mean of 63 +/- 13 cm of H(2)O (p < 0.001). The lowest increase in yield pressure of 17.5 cm was recorded after the first operation. Work-flow analysis revealed that this particular procedure took the longest, that bleeding from the liver was encountered, and shorter sutures than those used on all subsequent fundoplications may have compromised knot tying. CONCLUSIONS: CYP increases consistently after laparoscopic Nissen Fundoplication in young pigs. This parameter may be a good indicator of antireflux efficacy and functional quality of the result. Yield pressure measured through laparoscopic gastrostomy offers a new, feasible, and effective technique for the evaluation of antireflux surgery in an experimental setting. Moreover, this minimally invasive technique may become a simple investigative tool for other antireflux procedures.

Increased L1CAM (CD171) levels are associated with glioblastoma and metastatic brain tumors.

L1 cell adhesion molecule (L1CAM) is a member of the immunoglobulin-like cell-adhesion molecule family that was shown to be associated with a worse prognosis in several human cancers. L1 ectodomain shedding via vesicles or exosomes has been detected in extracellular fluids after cleavage from the cell surface by metalloproteases. We evaluated the presence of L1CAM in cyst fluid and tissue from glioblastomas or brain metastases.The amount of L1CAM in cyst fluid of 9 glioblastomas and 11 brain metastases was assessed using enzyme-linked immunosorbent assay (ELISA). Corresponding tumor tissue slices were stained immunohistochemically for L1CAM. Cerebrospinal fluid of 20 non-tumor patients served as controls.Mean levels of L1CAM in tumor cyst fluid were significantly higher in glioblastoma (6118 ±â€Š4095 ng/mL) and metastasis patients (8001 ±â€Š6535 ng/mL) than in CSF of control patients (714 ±â€Š22 ng/mL). The immunohistochemical expression of L1CAM in corresponding tissue was significantly higher in metastases than in glioblastomas.The present study demonstrates high levels of L1CAM in cyst fluid of glioblastoma and metastatic brain tumors. Soluble L1CAM may represent a motility promoting molecule in cancer progression, a co-factor for development of tumor cysts and a target for new treatment strategies.

L1 is associated with favorable outcome in neuroblastomas in contrast to adult tumors.

BACKGROUND: Neuroblastoma is the most common solid tumor in childhood with unconventional clinical behavior. L1, a neuronal cell adhesion molecule, is associated with poor survival in malignant adult tumors. The aim of the current study was to determine expression of L1 in pediatric neuroblastoma. METHODS: L1 expression was assessed on a tissue microarray with 66 surgically resected neuroblastoma samples by immunohistochemistry with a monoclonal antibody and peroxidase method. Additionally, mRNA expression was analyzed by reverse transcriptase-polymerase chain reaction with L1-specific primers. Data were correlated survival data by log rank test and Cox regression multivariate analysis. RESULTS: L1 was detected in 57 (86%) of 66 neuroblastomas, whereas 9 (14%) were L1 negative. Median survival of all children was 72 months. Analysis with Kaplan-Meier method revealed a surprising and contrary finding to adult tumor entities: an association of L1 positivity with better event-free and overall survival (P < .001 and P < .01 by log rank test). Multivariate Cox regression analysis showed an independent prognostic impact of L1 negativity for event-free and overall survival of the children (P < .05). CONCLUSIONS: In contrast to adult tumor entities, where L1 is associated with aggressive clinical behavior, our data show that L1 predicts good outcome in children with neuroblastoma. This novel finding suggests an inverse role of L1 in neuroblastoma. Future studies might focus on the molecular basis of the varying effect of L1 in different tumors.

Midkine as a prognostic marker for gastrointestinal stromal tumors.

PURPOSE: Midkine (MK), a heparin-binding growth factor, has an important role in cancer progression. The outcome of patients with gastrointestinal stromal tumors (GISTs) is correlated with tumor size and mitotic count. The aim of this study was to determine MK expression in GISTs. METHODS: Midkine was detected in 31 (55%) of 57 surgically resected GISTs by immunohistochemistry with a rabbit antibody against MK and peroxidase method. RESULTS: A significant worse outcome of MK-positive patients was found (P < 0.05; log rank test). Multivariate Cox regression analysis showed an independent prognostic impact (relative risk for overall survival 3.64; P < 0.05). Interestingly, MK expression was significantly associated with mitotic rate (P < 0.05; Chi-squared test), but not with tumor size (P = 0.97). CONCLUSIONS: Taken together, MK is a prognostic marker for GIST patients. MK might also be a useful peripheral tumor marker since it can be detected in peripheral serum. Future studies should involve higher GIST patient numbers including tumor and serum samples for detection of MK.

Microsatellite analysis in serum DNA as a diagnostic tool for distinction of patients with unknown pancreatic masses.

The clinical distinction between cancer and chronic pancreatitis is difficult in patients with pancreatic masses. To test whether detection of aberrant serum DNA could assist in this important differential diagnosis, we tested a panel of 12 microsatellitemarkers from chromosomes 17p, 17q, 13q, 9p, 5q, and 2p in the blood of 35 pancreatic cancer patients, 22 patients with chronic pancreatitis, and 20 healthy individuals. An average of 2.8 loss of heterozygosity (LOH) was found in 32 of 35 cancer patients of whom 30 (86%) had 2 or more LOH. LOH was also found in 7 of 22 pancreatitis patients but all these patients had only 1 LOH. No LOH was detected in healthy donors of comparable age. These data suggest that LOH analysis may be a substantial help for diagnosing pancreatic masses. An extension of the panel, perhaps in combination with a better selection of markers may further improve this assay.

Short tandem repeat polymorphisms of exon 4 in Kazal-type gene ECRG2 in pancreatic carcinoma and chronic pancreatitis.

BACKGROUND: Short tandem repeat (STR) polymorphisms in exon 4 of the Kazal-type esophageal cancer related gene (ECRG2) have been reported to be associated with esophageal carcinoma. Kazal-type genes are associated with cancer and pancreatic disease. The aim of the present study was to examine whether ECRG2 STR polymorphisms are associated with pancreatic carcinoma and chronic pancreatitis. MATERIALS AND METHODS: A total of 209 surgically treated patients were analyzed, 92 with pancreatic adenocarcinoma and 117 with chronic pancreatitis. We retrospectively analyzed genomic DNA from peripheral blood leukocytes for STR TCA3/TCA3, TCA3/TCA4 and TCA4/TCA4 in the noncoding region of exon 4 of ECRG2. Associations between STRs and survival of cancer patients were investigated using log-rank test. RESULTS: ECRG2 STR of highest incidence was TCA3/TCA3 [47 (51%) in pancreatic carcinoma; 59 (50%) in pancreatitis patients], followed by the TCA3/TCA4 [37 (40%); 54 (46%)] and TCA4/TCA4 [8 (9%); 4 (4%)] genotypes. No correlation in frequency of STRs comparing chronic pancreatitis and pancreatic cancer was determined using the Chi-squared test (p = 0.23). STR polymorphisms were not significantly associated with reduced tumor-specific or overall survival (p > 0.05; log-rank test). CONCLUSION: The data show that ECRG2 STR polymorphism TCA3/TCA3 in exon 4 is the most prevalent polymorphism found in pancreatic adenocarcinoma and chronic pancreatitis detected in peripheral blood. None of the polymorphisms was associated with poor clinical outcome in pancreatic cancer patients.

Similar patterns of loss of heterozygosity in serum of adenocarcinoma of the distal oesophagus and the cardia in early diagnosis.

BACKGROUND: Loss of heterozygosity (LOH) may be a valuable tool for detection of malignant proceedings. The aim of our study was to investigate LOH in the serum of patients with adenocarcinoma of the distal oesophagus and the cardia for diagnostic and prognostic utility. PATIENTS AND METHODS: Matched tumour and serum samples from 46 surgically treated patients with oesophageal adenocarcinoma and cardia carcinoma divided in two groups were analysed. Twelve markers were examined with a PCR-based microsatellite analysis. RESULTS: A similar high frequency of LOH (range from 77% to 96%) was detected in the tumour and serum of both groups, whereas no LOH was detected in 20 healthy individuals. However, no significant correlation between LOH incidence and clinicopathological characteristics and survival was found. CONCLUSION: The results indicate that DNA alterations in tumours of the oesophagus and cardia are uniform. The high frequency of LOH in tumour patients underlines the utility of this molecular approach as a diagnostic tool.

Microsatellite DNA alterations of gastrointestinal stromal tumors are predictive for outcome.

PURPOSE: In gastrointestinal stromal tumors (GIST), loss of heterozygosity (LOH) on chromosome 22 and its presumptive biological function has been described. The prognostic value of these and other DNA regions for patient survival remains unclear. EXPERIMENTAL DESIGN: Sixty patients who underwent surgery at our institution between 1992 and 2003 for GIST were histopathologically reclassified by immunohistochemistry and the GIST consensus group criteria 2001. Twenty-one microsatellite loci on chromosomes 3, 9, 13, 17, 18, and 22 were screened for alterations in tumor and healthy DNA. Survival was calculated by Kaplan-Meier plots. RESULTS: Eleven (18.3%) of 60 patients showed metastases at presentation. Thirteen (21.7%) of 60 were high-risk GISTs. LOH was found in all tumors. Twenty-eight (46.7%) of 60 showed more than two LOH in 21 microsatellite marker sites. The frequency of single marker LOH varied from 1.7% to 28.3% among tumors. Frequent LOH was found on chromosomes 22 and 17. The correlation of LOH positivity and the consensus scoring was significant (P=0.005, chi2 test). After a median observation time of 33.3 months (95% confidence interval, 23.9-42.6), overall survival was best for patients with tumors of very low, low, and intermediate risks with only 6 of 36 death events, whereas 14 of 24 high-risk and metastasized patients had died (P<0.001, log-rank test). Likewise, LOH significantly predicted survival (P=0.013) and the effect was particularly detrimental for LOH on chromosome 17 (P<0.001). CONCLUSIONS: LOH is a useful phenomenon for the prognosis of GIST. Rather than chromosome 22 markers, chromosome 17 markers independently predict survival.

Allelic loss of Hox11L1 gene locus predicts outcome of gastrointestinal stromal tumors.

Loss of heterozygosity (LOH) in tumors has been described to have prognostic impact. Hox11L1 gene, located on chromosome 2, has a role in proliferation of neuronal myenteric Cajal cells being the progenitor cells of GISTs. The aim was to examine the frequency and prognostic value of allelic loss of Hox11L1 gene locus in GISTs. Tumor and control DNA of 72 GIST patients was extracted after microdissection from tissue sections. Patients underwent surgery between 1992 and 2003 and were histopathologically reclassified. Microsatellite marker D2S286 on chromosomes 2 near Hox11L1 gene locus was used for detection of LOH by PCR and capillary electrophoresis. Survival was calculated by Kaplan-Meier plots. LOH was found in 7 (10%) of 72 GISTs. Fifty-four (75%) cases did not show LOH. Eleven (15%) were homozygous and consequently non-informative. Survival analysis (n=59) revealed a significantly worse tumor-specific and relapse-free survival for GIST patients with LOH in the tumor by univariate analysis (p<0.05 by log-rank test; median follow-up time 37 months). LOH of Hox11L1 gene locus is a useful parameter for prognosis of GIST. The data propose that Hox11L1 has a role in tumorigenesis in GISTs.

Absence of L1 in pancreatic masses distinguishes adenocarcinomas from poorly differentiated neuroendocrine carcinomas.

BACKGROUND: Pancreatic adenocarcinoma is a tumor with fatal outcome. Cell adhesion molecules, such as L1 (CD171), have an essential function in tumor progression. L1 has been shown to be specifically expressed in poorly differentiated neuroendocrine carcinomas of the pancreas. The aim of this study was to determine the expression of L1 in pancreatic adenocarcinomas to evaluate whether L1 might differentiate between pancreatic carcinomas of neuroendocrine and ductal origin. MATERIALS AND METHODS: L1 expression was retrospectively analyzed in 111 cases of pancreatic adenocarcinomas by immunohistochemistry on paraffin sections of primary tumors. Staining was performed by the peroxidase technique with monoclonal antibody against human L1. All tumors were classified according to the most recent TNM classification. RESULTS: The focal expression of L1 was detected in 2 (2%) out of 111 pancreatic carcinomas only, the remaining 109 (98%) being L1-negative. No expression was found in acinar or ductal cells of normal pancreatic tissue. CONCLUSION: Our data suggest that L1 is expressed in few cases of pancreatic ductal adenocarcinoma. Since L1 was previously found to be expressed specifically in neuroendocrine pancreatic carcinomas, its absence in unclear pancreatic masses might hint at a ductal origin for a malignant pancreatic tumor.