A case of unusual histiocytic colitis in a chronic alcoholic obese patient with ankylosing spondylitis.

A 64 year-old Caucasian man was first investigated 21 years ago for persistent diarrhoea. A colonoscopy revealed an erosive pancolitis with unusual vacuolated macrophages. Characteristics of ulcerative colitis or Crohn's disease were absent. Similar findings were observed consistently over the following years. A treatment with Sulfasalazine, Methotrexate or Budesonide was efficient. Histiocytic colitis is rare, and the various causes and different diagnoses are reviewed. The cause for the chronic pancolitis in this obese chronic alcoholic remains unknown at the time of writing. Links to the dyslipidaemia and chronic ankylosing spondylitis presented by the patient are possible hypotheses worth investigating further.

Review of the quality of total mesorectal excision does not improve the prediction of outcome.

AIM: A fair to moderate concordance in grading of the total mesorectal excision (TME) surgical specimen by local pathologists and a central review panel has been observed in the PROCARE (Project on Cancer of the Rectum) project. The aim of the present study was to evaluate the difference, if any, in the accuracy of predicting the oncological outcome through TME grading by local pathologists or by the review panel. METHOD: The quality of the TME specimen was reviewed for 482 surgical specimens registered on a prospective database between 2006 and 2011. Patients with a Stage IV tumour, with unknown incidence date or without follow-up information were excluded, resulting in a study population of 383 patients. Quality assessment of the specimen was based on three grades including mesorectal resection (MRR), intramesorectal resection (IMR) and muscularis propria resection (MPR). Using univariable Cox regression models, local and review panel histopathological gradings of the quality of TME were assessed as predictors of local recurrence, distant metastasis and disease-free and overall survival. Differences in the predictions between local and review grading were determined. RESULTS: Resection planes were concordant in 215 (56.1%) specimens. Downgrading from MRR to MPR was noted in 23 (6.0%). There were no significant differences in the prediction error between the two models; local and central review TME grading predicted the outcome equally well. CONCLUSION: Any difference in grading of the TME specimen between local histopathologists and the review panel had no significant impact on the prediction of oncological outcome for this patient cohort. Grading of the quality of TME as reported by local histopathologists can therefore be used for outcome analysis. Quality control of TME grading is not warranted provided the histopathologist is adequately trained.

Lymph node ratio and surgical quality are strong prognostic factors of rectal cancer: results from a single referral centre.

AIM: Nodal stage is a strong prognostic factor of oncological outcome of rectal cancer. To compensate for the variation in total number of harvested nodes, calculation of the lymph node ratio (LNR) has been advocated. The aim of the study was to compare the impact, on the long-term oncological outcome, of the LNR with other predictive factors, including the quality of total mesorectal excision (TME) and the state of the circumferential resection margin. METHOD: Consecutive patients having elective surgery for nonmetastatic rectal cancer were extracted from a prospectively maintained database. Retrospective uni- and multivariate analyses were performed based on patient-, surgical- and tumour-related factors. The prognostic value of the LNR on overall survival (OS) and on overall recurrence-free survival (ORFS) was assessed and a cut-off value was determined. RESULTS: From 1998 to 2013, out of 456 patients, 357 with nonmetastatic disease were operated on for rectal cancer. Neoadjuvant radiochemotherapy was administered to 66.7% of the patients. The mean number of lymph nodes retrieved was 12.8 ± 8.78 per surgical specimen. A lower lymph node yield was obtained in patients who received neoadjuvant chemoradiotherapy (11.8 vs 14.2; P = 0.014). The 5-year ORFS was 71.8% and the 5-year OS was 80.1%. Multivariate analysis confirmed LNR, the quality of TME and age to be independent prognostic factors of OS. LNR, age and perineural infiltration were independently associated with ORFS. Low- and high-risk patients could be discriminated using an LNR cut-off value of 0.2. CONCLUSION: LNR is an independent prognostic factor of OS and ORFS. In line with the principles of optimal surgical management, the quality of TME and lymph node yield are essential technical requirements.

Pathological responses after angiogenesis or EGFR inhibitors in metastatic colorectal cancer depend on the chemotherapy backbone.

BACKGROUND: Optimal preoperative treatment before colorectal cancer metastases (CRCM) resection remains unclear. This study evaluated pathological responses (pR) in CRCM resected after chemotherapy alone or combined with angiogenesis or epidermal growth factor receptor (EGFR) inhibitors. METHODS: Pathological response was retrospectively evaluated on 264 resected metastases from 99 patients. The proportion of responding metastases after different preoperative treatments was reported and compared. Patient's progression-free survival (PFS) and overall survival (OS) were compared based on pR. RESULTS: The combination of anti-angiogenics with oxaliplatin-based chemotherapy resulted in more pR than when they were combined with irinotecan-based chemotherapy (80% vs 50%; P<0.001). Inversely, the combination of EGFR inhibitors with oxaliplatin-based chemotherapy seemed to induce fewer pR than when they were combined with irinotecan-based treatment (53% vs 72%; P=0.049). Overall survival at 5 years was improved for patients with a pR in all resected metastases compared with those who did not achieve a pR (68.5% vs 32.6%; P=0.023) and this response was the only factor predicting OS in a multivariate analysis. CONCLUSION: The chemotherapy partner combined with angiogenesis or EGFR inhibitors influenced pR in resected CRCM. In our exploratory analysis anti-angiogenic/oxaliplatin-based regimens and anti-EGFR/irinotecan-based regimens were associated with the highest pR. Prospective randomised trials should be performed to validate these observations.

Escalating incidence of eosinophilic esophagitis in Canton of Vaud, Switzerland, 1993-2013: a population-based study.

BACKGROUND: Eosinophilic esophagitis (EoE) is a chronic, inflammatory disease of the esophagus with a rapidly increasing incidence. However, population-based epidemiologic data on EoE are rare and limited to regions with less than 200,000 inhabitants. We evaluated the incidence and prevalence of EoE over time in Canton of Vaud, Switzerland. MATERIALS AND METHODS: Canton of Vaud lies in the French-speaking, Western part of Switzerland. As of December 2013, it had a population of 743,317 inhabitants. We contacted all pathology institutes (n = 6) in this canton to identify patients that have been diagnosed with esophageal eosinophilia between 1993 and 2013. We then performed a chart review in all adult and pediatric gastroenterology practices to identify patients with EoE. RESULTS: Of 263 patients with esophageal eosinophilia, a total of 179 fulfilled the diagnostic criteria for EoE. Median diagnostic delay was 4 (IQR 1-9) years. No patient was diagnosed with EoE prior to 2003. Incidence of EoE increased from 0.16/100,000 inhabitants in 2004 to 6.3/100,000 inhabitants in 2013 (P < 0.001). The cumulative EoE prevalence in 2013 was 24.1/100,000. The incidence in males was 2.8 times higher (95% CI 2.01-3.88, P < 0.001) when compared to that in females. The annual EoE incidence was 10.6 times higher (95%-CI 7.61-14.87, P < 0.001) in the period from 2010 to 2013 when compared to that in the period from 1993 to 2009. CONCLUSIONS: The incidence and cumulative prevalence of EoE in Canton of Vaud, Switzerland, has rapidly increased in the past 10 years.

Solitary extramedullary plasmocytoma of the thyroid: a case report and histological approach to plasma cells infiltrate in the thyroid gland.

BACKGROUND: Solitary extramedullary plasmacytoma (SEP) is a rare malignant neoplasm arising from plasma cells. SEP mostly occurs in the upper respiratory tract. Thyroid gland is rarely affected (<78 cases). METHODS/RESULTS: We describe the case of a 78-year-old woman presenting a rapidly enlarging palpable thyroid mass. Neck computed tomography scan showed enlargement of both thyroid lobes. Laboratory tests were normal, including serum protein level with no monoclonal gamma globulin peak. Cytology was suspicious for lymphoma. Biopsy showed an infiltrating neoplasm composed of atypical tumor cells with abundant cytoplasm and eccentric nuclei. These revealed diffuse immunoreactivity for CD138 and predominant staining for immunoglobulin kappa light chains. Clinical workup for multiple myeloma was negative. CONCLUSIONS: SEP should be considered in the differential diagnosis of a rapidly enlarging thyroid nodule and be distinguished from involvement of thyroid in multiple myeloma, mucosa-associated lymphoid tissue lymphoma, plasma cell granuloma and medullary carcinoma. Clinical correlation and immunohistochemistry are crucial in avoiding pitfalls.

Dynamics of allograft fibrosis in pediatric liver transplantation.

Progressive liver allograft fibrosis (LAF) is well known to occur long term, as shown by its high prevalence in late posttransplant liver biopsies (LBs). To evaluate the influence of clinical variables and immunosuppression on LAF progression, LAF dynamic was assessed in 54 pediatric liver transplantation (LT) recipients at 6 months, 3 and 7 years post-LT, reviewing clinical, biochemical data and protocol LBs using METAVIR and the liver allograft fibrosis score, previously designed and validated specifically for LAF assessment. Scoring evaluations were correlated with fibrosis quantification by morphometric analysis. Progressive LAF was found in 74% of long-term patients, 70% of whom had unaltered liver enzymes. Deceased grafts showed more fibrosis than living-related grafts (p = 0.0001). Portal fibrosis was observed in correlation with prolonged ischemia time, deceased grafts and lymphoproliferative disease (p = 0.001, 0.006 and 0.012, respectively). Sinusoidal fibrosis was correlated with biliary complications (p = 0.01). Centrilobular fibrosis was associated with vascular complications (p = 0.044), positive autoantibodies (p = 0.017) and high gamma-globulins levels (p = 0.028). Steroid therapy was not associated with reduced fibrosis (p = 0.83). LAF could be viewed as a dynamic process with mostly progression along the time. Peri- and post-LT-associated factors may condition fibrosis development in a specific area of the liver parenchyma.

Pancreatic neuroendocrine tumour grading on endoscopic ultrasound-guided fine needle aspiration: high reproducibility and inter-observer agreement of the Ki-67 labelling index.

OBJECTIVES: Assessment of proliferation by the Ki-67 labelling index (Ki67-LI) is an important parameter of pancreatic neuroendocrine tumour (pNET) prognosis on resection specimens. Ki67-LI values for grading are not fully established on endoscopic ultrasound-guided fine needle aspiration (EUS-FNA). The aim of the study was to determine the accuracy of Ki67-LI on EUS-FNA to predict a final grade of pNET and to analyse the relationship between cytological grading and progression-free survival (PFS). METHODS: Between 1996 and 2010, 46 pNETs (33 were resected) from 45 patients were diagnosed by EUS-FNA. Ki67-LI was evaluated on cytological and histological material for each tumour and classified according to the 2010 WHO grading system. RESULTS: A very good inter-observer agreement for Ki67-LI on EUS-FNA and surgical specimens, respectively, were obtained. Discrepancies were observed between histology and cytology, especially in grade 2 (G2) tumours, where cytology underestimated grading owing to tumour heterogeneity. Still, EUS-FNA was able to distinguish a poor prognostic group, as the actuarial PFS of cytological (c) G3 tumours was 10 ± 4 months versus 29 ± 7 and 68 ± 10 for cG2 and cG1 tumours, respectively (P < 0.0001). CONCLUSION: This study attests the reproducibility of Ki67-LI of pNETs whether counted on cytology or histology with a very good inter-observer correlation. Determination of Ki67-LI on EUS-FNA of pNETs should be included systematically in their prognostic work-up.

Combination of gemcitabine and cetuximab in patients with advanced cholangiocarcinoma: a phase II study of the Belgian Group of Digestive Oncology.

BACKGROUND: Cholangiocarcinomas are uncommon tumours with a poor prognosis, that frequently present epidermal growth factor receptor overexpression. METHODS: In a multi-centre phase II trial, patients with unresectable cholangiocarcinoma, naïve to chemotherapy, received Cetuximab (400 mg/m(2) at week 1, then 250 mg/m(2)/week) and Gemcitabine (1 g/m(2) on day 1, 8 and 15 every 4 weeks). Primary end point was progression-free survival (PFS) rate at 6 months, using a Simon 2-stage design. Moreover, we assessed the impact of KRAS status and skin toxic effect on efficacy. RESULTS: Forty-four patients (41% locally advanced/59% metastatic) were enrolled. Median age was 61.5 years; ECOG PS was 0 (68%) or 1. Six months PFS reached 47%. Median OS was 13.5 months [95% confidence interval (CI) 9.8-31.8 months]. Nine patients (20.4%) had PR and disease-control rate was 79.5%. Grade 3/4-related toxic effects were haematological (52.2%), skin rash (13.6%) and fatigue (11.4%). KRAS mutations were found in 7 of 27 patients and had no influence on PFS. Skin toxic effect ≥grade 2 was associated with increased PFS (P = 0.05). CONCLUSION(S): Our study met its primary end point, suggesting that Gemcitabine-Cetuximab has activity in cholangiocarcinoma. KRAS status was not associated with PFS, unlike skin toxic effect, which could be used as a surrogate marker for efficacy. ClinicalTrials.gov Identifier: NCT00747097.

Need for objective and reproducible criteria in histopathological assessment of total mesorectal excision specimens: lessons from a national improvement project.

AIM: Data on quality control of the pathologic evaluation of total mesorectal excision (TME) specimens are scarce. We aimed to assess differences between evaluation by local pathologists participating in PROject on CAncer of the REctum (PROCARE; a Belgian improvement project on rectal cancer) and by a review panel of experts. METHOD: Based on photographic material and histopathology slides, a Review Committee of gastrointestinal expert pathologists re-evaluated the mesorectal plane, the tumour differentiation grade, the (y)pT stage and the tumour regression grade in 444 patients previously routinely assessed by local pathologists. RESULTS: The surgical plane was reported in 89% of patients and the circumferential resection margin in 88% of patients by the local pathologist. The median number of lymph nodes harvested in patients undergoing neoadjuvant radiochemotherapy was 11 and 14 in the other patients. The Review Committee downgraded the surgical plane from (intra)mesorectal to intramuscular in 17% of patients, and upgraded it from intramuscular to (intra)mesorectal in 27%. Tumour differentiation grade, T stage and tumour regression grade differed between local pathologists and the Review Committee in 15%, 10% and 38%, respectively, of patients. T stage was upgraded, mainly from T2 to T3, in 8% of patients. Tumour regression was judged by the Review Committee to be less advanced in 15% of patients. CONCLUSION: Acknowledging some shortcomings, this study gives a realistic view of clinical practice. There are differences in interpretation with regard to both macroscopic and microscopic analysis of TME specimens. These findings indicate a need for more objective and reproducible criteria in histopathology. Being aware of this is a first step for improvement.

Histological and immunohistochemical revision of hepatocellular adenomas: a learning experience.

Light has been shed on the genotype/phenotype correlation in hepatocellular adenoma (HCA) recognizing HNF1 α -inactivated HCA (H-HCA), inflammatory HCA (IHCA), and ß -catenin-activated HCA (b-HCA). We reviewed retrospectively our surgical HCA series to learn how to recognize the different subtypes histopathologically and how to interpret adequately their immunohistochemical staining. From January 1992 to January 2012, 37 patients underwent surgical resection for HCA in our institution. Nine had H-HCA (25%) characterized by steatosis and loss of L-FABP expression; 20 had IHCA (55.5%) showing CRP and/or SAA expression, sinusoidal dilatation, and variable inflammation; and 1 patient had both H-HCA and IHCA. In 5 patients (14%), b-HCA with GS and ß -catenin nuclear positivity was diagnosed, two already with hepatocellular carcinoma. Two cases (5.5%) remained unclassified. One of the b-HCA showed also the H-HCA histological and immunohistochemical characteristics suggesting a subgroup of ß -catenin-activated/HNF1 α -inactivated HCA, another b-HCA exhibited the IHCA histological and immunohistochemical characteristics suggesting a subgroup of ß -catenin-activated/inflammatory HCA. Interestingly, three patients had underlying vascular abnormalities. Using the recently published criteria enabled us to classify histopathologically our retrospective HCA surgical series with accurate recognition of b-HCA for which we confirm the higher risk of malignant transformation. We also underlined the association between HCA and vascular abnormalities.

Characterization of ß-cell plasticity mechanisms induced in mice by a transient source of exogenous insulin.

ß-Cell plasticity governs the adjustment of ß-cell mass and function to ensure normoglycemia. The study of how ß-cell mass is controlled and the identification of alternative sources of ß-cells are active fields of research. ß-Cell plasticity has been implicated in numerous physiological and pathological conditions. We developed a mice model in which we induced major ß-cell mass atrophy by implanting insulin pellets (IPI) for 7 or 10 days. The implants were then removed (IPR) to observe the timing and characteristics of ß-cell regeneration in parallel to changes in glycemia. Following IPR, the endocrine mass was reduced by 60% at day 7 and by 75% at day 10, and transient hyperglycemia was observed, which resolved within 1 wk. Five days after IPR, enhanced ß-cell proliferation and an increased frequency of small islets were observed in 7-day IPI mice. ß-Cell mass was fully restored after an additional 2 days. For the 10-day IPI group, ß-cell and endocrine mass were no longer significantly different from those of the control group at 2 wk post-IPR. Furthermore, real-time quantitative PCR analysis of endocrine structures isolated by laser capture microdissection indicated sequentially enhanced expression of the pancreatic transcription factors ß(2)/NeuroD and Pdx-1 post-IPR. Thus, our data suggest this mouse model of ß-cell plasticity not only relies on replication but also involves enhanced cell differentiation plasticity.

Novel histologic scoring system for long-term allograft fibrosis after liver transplantation in children.

The existing systems for scoring fibrosis were not developed to evaluate transplanted livers. Our aim was to design and validate a novel fibrosis scoring system specifically adapted to assess liver allograft fibrosis (LAF). Clinical data, histology, transient elastography (TE) and AST/platelet ratio index (APRI) were reviewed in 38 pediatric liver transplant (LT) recipients. Protocol liver biopsies performed at 6 months and 7 years post-LT were reviewed by three pathologists who assessed LAF using the METAVIR and Ishak systems. LAF was also scored separately in portal (0-3), sinusoidal (0-3) and centrolobular areas (0-3). Scoring evaluations were correlated with fibrosis quantification using morphometry, and also with TE and APRI. Statistical correlations between morphometry and METAVIR were 0.571 (p < 0.000) and 0.566 (p < 0.000) for the Ishak system. The novel score (0-9) for separate assessment of portal, sinusoidal and centrolobular fibrosis showed a better correlation with morphometry (0.731; p < 0.000) and high intra-/interobserver agreement (0.966; p < 0.000 and 0.794; p < 0.000, respectively). No correlation was found between TE or APRI and morphometry or the three histologic scores. In conclusion, this novel semiquantitative fibrosis scoring system seems to more accurately reflect LAF than the existing scoring system and may become a practical tool for staging fibrosis in LT.

Impact of steroid-avoidance immunosuppression on long-term outcome after liver transplantation for HCV cirrhosis: the need for well documented long-term follow-up.

AIM: study impact of steroid avoidance on HCV recurrence after transplantation. METHODS AND MATERIAL: 35 HCV pats, being part of prospective, randomized, double-blind, placebo-controlled study comparing Tacrolimus (TAC)-Placebo (PLAC) (n = 14) to TAC-short-term (2 mo) low-dose steroid (STER) (n = 21), had 5 years follow-up. Primary endpoint was 1 and 5 years survival; secondary (composite) endpoint comprised HCV related cirrhosis, re-transplantation (re-LT) and death. RESULTS: 1 and 5-years survival were 93% and 75% in TAC-PLAC group; 91% and 66% in TAC-STER group (p 0.38). Two (14.3%) TAC-PLAC pats died due to HCV cirrhosis at 54 and 72 mo; 7 (33%) TAC-STER pats died due to cholestatic hepatitis at 5.8 and 9 mo, to cirrhosis at 18, 22, 34, 73 and 79 mo (p 0.20). Composite endpoint at 5 years didn't show advantage in favor of TAC-PLAC patients (5/14 [35.7%] vs. 9/21 [42.8%] pts, p.0.69). Early biopsies seemed more favorable in TAC-PLAC pats; at 5 years results were identical for both groups. Only 1 (7.1%) TAC-PLAC and 2 (9.5%) TAC-STER pats needed rejection treatment. CONCLUSION: immunosuppression using steroid avoidance or short-term use had similar outcomes. Well documented long-term follow-up, including biopsies, is necessary in order to make conclusions in relation to impact of steroid use on outcome of HCV liver recipients.

Human equilibrative nucleoside transporter 1 (hENT1) expression is a potential predictive tool for response to gemcitabine in patients with advanced cholangiocarcinoma.

BACKGROUND: Cholangiocarcinoma (CC) is a rare cancer of the liver. Surgery offers the only chance for cure. When surgery is unfeasible, chemotherapy is the backbone of treatment. The combined administration of cisplatin and gemcitabine is considered standard of care. Human equilibrative nucleoside transporter 1 (hENT1) is the major transporter responsible for gemcitabine uptake into cells. hENT1 expression is associated with an increased survival for patients receiving gemcitabine after pancreatic cancer surgery, suggesting that hENT1 is predictive of response to gemcitabine. AIM: To determine whether there is a correlation between the expression of hENT1 and disease outcome in CC. METHODS: A retrospective study on 43 patients treated at our centre with a locally advanced or metastatic CC, who received first line treatment with gemcitabine, was performed. RESULTS: For the whole population, median Progression Free Survival (PFS) and overall survival (OS) were 4.0 (95% Confidence Interval 2.7-5.3 months) and 10.0 months (95%CI 6.8-13.2 months), respectively. From the 26 samples available for hENT1 staining, 18 (69%) and 8 (31%) patients had high and low hENT1 immunostaining, respectively. The median PFS were 2.0 versus 6.0 months for low versus high staining respectively (p = 0.012). The median OS were 5.0 versus 11.0 months for low versus high staining, respectively (p = 0.036). On multivariate analysis, hENT1 expression was the single independent predictive factor associated with prolonged PFS (HR 0.35, p = 0.023) and OS (HR 0.41, p = 0.046). CONCLUSION: In this study we show the potential of hENT1 expression as a predictor of outcome in CC treated with gemcitabine. Larger studies are necessary to confirm these promising results.

Familial adenomatous polyposis: clinical presentation, detection and surveillance.

Colorectal cancer (CRC) is a leading cause of cancer related death in the western countries. It remains an important health problem, often under-diagnosed. The symptoms can appear very late and about 25% of the patients are diagnosed at metastatic stage. Familial adenomatous polyposis (FAP) is an inherited colorectal cancer syndrome, characterized by the early onset of hundred to thousands of adenomatous polyps in the colon and rectum. Left untreated, there is a nearly 100% cumulative risk of progression to CRC by the age of 35-40 years, as well as an increased risk of various other malignancies. CRC can be prevented by the identification of the high risk population and by the timely implementation of rigid screening programs which will lead to special medico-surgical interventions.

Morphological mosaicism of the pancreatic islets: a novel anatomopathological form of persistent hyperinsulinemic hypoglycemia of infancy.

BACKGROUND: Morphological studies of the pancreas in persistent hyperinsulinemic hypoglycemia of infancy (PHHI) have focused on the diagnosis of focal vs. diffuse forms, a distinction that determines the optimal surgical management. ABCC8 or KCNJ11 genomic mutations are present in most of them. AIM: Our aim was to report a new form of PHHI with peculiar morphological and clinical characteristics. RESEARCH DESIGN AND METHODS: Histopathological review of 217 pancreatic PHHI specimens revealed 16 cases morphologically different from diffuse and focal forms. They were analyzed by conventional microscopy, quantitative morphometry, immunohistochemistry, and in situ hybridization. RESULTS: Their morphological peculiarity was the coexistence of two types of islet: large islets with cytoplasm-rich ß-cells and occasional enlarged nuclei and shrunken islets with ß-cells exhibiting little cytoplasm and small nuclei. In small islets, ß-cells had abundant insulin content but limited amount of Golgi proinsulin. Large islets had low insulin storage and high proinsulin production and were mostly confined to a few lobules. No evidence for K(ATP) channels involvement or 11p15 deletion was found. Genomic mutations for ABCC8, KCNJ11, and GCK were absent. Patients had normal birth weight and late hypoglycemia onset and improved with diazoxide. Ten were cured by limited pancreatectomy. Six recurred after surgery and were medically controlled. CONCLUSION: This new form of PHHI is characterized by a morphological mosaicism. Pathologists should recognize this mosaicism on intraoperative frozen sections because it is often curable by partial pancreatectomy. The currently unknown genetic background does not involve the classical genomic mutations responsible for diffuse and focal PHHI.

ABCC8 and KCNJ11 molecular spectrum of 109 patients with diazoxide-unresponsive congenital hyperinsulinism.

BACKGROUND: Congenital hyperinsulinism (CHI) is characterised by an over secretion of insulin by the pancreatic ß-cells. This condition is mostly caused by mutations in ABCC8 or KCNJ11 genes encoding the SUR1 and KIR6.2 subunits of the ATP-sensitive potassium (K(ATP)) channel. CHI patients are classified according to their responsiveness to diazoxide and to their histopathological diagnosis (either focal, diffuse or atypical forms). Here, we raise the benefits/limits of the genetic diagnosis in the clinical management of CHI patients. METHODS: ABCC8/KCNJ11 mutational spectrum was established in 109 diazoxide-unresponsive CHI patients for whom an appropriate clinical management is essential to prevent brain damage. Relationships between genotype and radiopathological diagnosis were analysed. RESULTS: ABCC8 or KCNJ11 defects were found in 82% of the CHI cases. All patients with a focal form were associated with a single K(ATP) channel molecular event. In contrast, patients with diffuse forms were genetically more heterogeneous: 47% were associated with recessively inherited mutations, 34% carried a single heterozygous mutation and 19% had no mutation. There appeared to be a predominance of paternally inherited mutations in patients diagnosed with a diffuse form and carrying a sole K(ATP) channel mutation. CONCLUSIONS: The identification of recessively inherited mutations related to severe and diffuse forms of CHI provides an informative genetic diagnosis and allows prenatal diagnosis. In contrast, in patients carrying a single K(ATP) channel mutation, genetic analysis should be confronted with the PET imaging to categorise patients as focal or diffuse forms in order to get the appropriate therapeutic management.

Accurate KRAS mutation testing for EGFR-targeted therapy in colorectal cancer: emphasis on the key role and responsibility of pathologists.

Patients with metastatic colorectal cancer and KRAS mutation are unlikely to benefit from treatment with anti-EGFR antibodies, and testing for KRAS mutation in this setting is recommended. Pathologists have a crucial role in accurate testing for KRAS mutations, whether or not testing is performed in their own laboratory, as mutation analysis is performed on paraffin embedded tissue selected by the pathologists. The type of fixative used is a very important issue, as some fixatives do not allow molecular testing. Pathologists must select the most appropriate tumoral tissue block for KRAS mutation analysis and hence, must know the sensitivity of the KRAS mutation detection methodology utilized in their reference laboratory. It is essential that they select a tissue block that contains enough percentage of viable tumour cells, as false negative results will occur when the sample is contaminated with high levels of nontumour elements. Pathologists not only have to recognize the area of invasive carcinoma and distinguish it from non-invasive neoplastic components, but also have to estimate the percentage of necrotic debris and nontumoural elements. For tests that require a high percentage of tumour cells, macrodissection before extraction of nucleic acids is often indicated. The primary pathologists in addition are responsible for preparation of the pathology report for the tissue block on which the KRAS mutation analysis was performed and should transmit the results to the requesting clinician. Pathologists should participate in a multidisciplinary oncologic consult to achieve correct interpretation of the results e.g. in case of potential false negative results.