The Voronoi theory of the normal liver lobular architecture and its applicability in hepatic zonation.

The precise characterization of the lobular architecture of the liver has been subject of investigation since the earliest historical publications, but an accurate model to describe the hepatic lobular microanatomy is yet to be proposed. Our aim was to evaluate whether Voronoi diagrams can be used to describe the classic liver lobular architecture. We examined the histology of normal porcine and human livers and analyzed the geometric relationships of various microanatomic structures utilizing digital tools. The Voronoi diagram model described the organization of the hepatic classic lobules with overall accuracy nearly 90% based on known histologic landmarks. We have also designed a Voronoi-based algorithm of hepatic zonation, which also showed an overall zonal accuracy of nearly 90%. Therefore, we have presented evidence that Voronoi diagrams represent the basis of the two-dimensional organization of the normal liver and that this concept may have wide applicability in liver pathology and research.

Needle core biopsy in the diagnosis of pediatric thyroid neoplasms: a single institution retrospective review.

PURPOSE: Our institution routinely utilizes needle core biopsy (NCB), instead of fine needle aspiration, in the evaluation of pediatric thyroid nodules. This practice initially arose from limited cytopathology services in our hospital. Given the lack of information regarding the utility of NCB in diagnosing pediatric thyroid neoplasms, we set out to review our institution's experience with this technique. METHODS: We performed a single institution retrospective chart review of all children who underwent thyroidectomy for primary thyroid pathology. RESULTS: Seventy-four patients, with a mean age of 12.9 ± 4.5 (SD) years, underwent partial or total thyroidectomy between 2002 and 2010. Seven of these patients had medically refractive hyperthyroidism. The remaining 67 patients had one or more thyroid nodules as identified by ultrasound. 24 (36 %) of these cases were malignant on final pathology. 14 (58 %) of the malignant cases were papillary thyroid carcinoma. 46 of the thyroid nodule cases underwent pre-operative NCB. Biopsy results for these patients were non-diagnostic in 6 (13 %), benign in 11 (24 %), atypical in 17 (37 %), and malignant in 12 (26 %). There were no complications arising from NCB. Sensitivity of NCB for diagnosing papillary carcinoma (PC) and follicular neoplasm was calculated at 0.88 (0.47-1.0, 95 % CI) and 0.84 (0.60-0.97, 95 % CI), respectively. Of the 28 patients not undergoing preoperative NCB, 12 underwent hemithyroidectomy, with one patient (8 %) requiring completion thyroidectomy for PC. Overall, the sensitivity of NCB in diagnosing PC and follicular thyroid neoplasms was 0.85 (0.55-0.99, 95 % CI), while the specificity was 0.63 (0.42-0.82, 95 % CI). CONCLUSIONS: Needle core biopsy appears to have a low rate of associated complications, and its sensitivity for diagnosing PC and follicular neoplasm is comparable to what has been reported for fine needle aspiration biopsy in a similar patient population.

Morbidly obese paediatric patients are not adequately screened for comorbidities.

Although childhood obesity is common, many paediatric practitioners are not familiar with screening for its associated, serious comorbidities. We aimed to determine the adequacy of screening for nine well-recognized comorbidities in outpatients with severe morbid obesity (body mass index [BMI] ≥50 kg m(-2) ) seen in a large tertiary paediatric hospital. Patients with a BMI of ≥50 kg m(-2) seen at Texas Children's Hospital during calendar year 2009 were identified. Their medical records were reviewed for any documentation where hypertension, cardiac dysfunction, sleep apnoea, hepatosteatosis, diabetes, pseudotumour cerebri, dyslipidemia, orthopaedic issues and depression were noted and/or addressed as evidence of clinician awareness of these problems. We identified 123 patients seen at least once in 2009, with an average of 3.4 physician visits per patient and by an average of 2 different specialists. Hypertension screening was the most documented (91% of patients) and depression screening was the least documented (41%) in this patient cohort. Twelve patients (10%) had documented screening for all nine comorbidities. Overall, 55 patients (45%) had five or fewer of the nine comorbidities noted and/or addressed in the medical record. Adequate screening for comorbidities occurs in approximately half of children with severe morbid obesity, which means that many of these comorbidities are not being identified or treated. Educational programmes and new methodologies are needed to ensure comprehensive care of children with morbid obesity.

Is histological diagnosis of primary liver carcinomas with fibrous stroma reproducible among experts?

AIMS: In the era of targeted therapeutics, histological typing of hepatobiliary carcinomas has major clinical implications. Little is known about the reproducibility of the pathological diagnosis of primary liver carcinomas. Therefore, this study aimed to evaluate the worldwide variation in the pathological expert diagnoses of primary liver carcinomas with fibrous stroma in patients who did not have cirrhosis. METHODS: A single set of slides was selected from 25 tumours, and this set was reviewed independently by 12 pathologists who have worldwide expertise in liver tumours. Reproducibility of the diagnoses was evaluated by Light's kappa, and diagnoses were clustered by multidimensional scaling. Immunohistochemistry was performed after histological review. RESULTS: The interobserver reproducibility for diagnosis of hepatocellular carcinoma subtypes and cholangiocarcinomas was poor (kappa 0.23-0.52), even when the experts considered that the diagnosis required no additional stains or clinical information. Interestingly, multidimensional scaling revealed three main clusters of tumours: hepatocellular carcinoma with no other specifications (n = 13), fibrolamellar hepatocellular carcinoma (n = 3) and cholangiocarcinoma (n = 9). Using immunohistochemistry, these histological clusters correlated with expression of anti-hepatocyte and anti-cytokeratin 19 (p<0.001). CONCLUSIONS: The results demonstrate the poor reproducibility among experts of the pathological diagnosis of primary liver carcinomas with fibrous stroma in patients who did not have cirrhosis, and highlight that the systematic use of immunohistochemistry may improve the diagnostic accuracy.

Expression of the coxsackievirus- and adenovirus receptor in gastrointestinal cancer correlates with tumor differentiation.

Modified adenoviruses represent a new approach to treatment of gastrointestinal cancer. However, their uptake by cells in many cases requires the major receptor for adenoviruses, the coxsackievirus and adenovirus receptor (CAR). Thus, lack of CAR expression is a potential cause of intrinsic resistance of tumor cells to this type of treatment. To evaluate this, we studied the localization of CAR protein in normal and malignant gastrointestinal tissues. In normal tissues, CAR was concentrated at sites of cell-cell interaction, in particular at the apico-lateral cellular surface. Expression was particularly strong around bile and pancreatic ducts, which is in agreement with CAR's physiological function as a tight-junction protein. In GI malignancies (esophageal, pancreatic, colorectal and liver cancer), expression of the receptor varied substantially. Loss of CAR expression at cell-cell junction was evident in many samples. A significant correlation between CAR expression and histological grade was found, with moderately to poorly differentiated tumors most frequently demonstrating loss or reduction of CAR expression. These data indicate that CAR expression is frequently altered in gastrointestinal malignancy, potentially reducing the efficacy of adenovirus-based therapies.

Increased engraftment and GVHD after in utero transplantation of MHC-mismatched bone marrow cells and CD80low, CD86(-) dendritic cells in a fetal mouse model.

BACKGROUND: Bone marrow transplantation (BMT) is the only known cure for a variety of inherited diseases and requires the administration of high doses of immunosuppressive and myeloablative therapy. Because the fetus is immunoincompetent early in gestation, in utero stem cell transplantation (IUT) could avoid the need for this toxic conditioning. A major limitation to date of IUT is the low level of engraftment and failure to induce tolerance. Dendritic cells (DC) are considered very potent antigen-presenting cells, but DC progenitors (pDC) are strongly tolerogenic. METHODS: We examined the effect of donor pDC on the degree of engraftment and tolerance induction after IUT. Bone marrow-derived pDC (CD80low, CD86-) from male C57BL/6 mice (H2b) were injected with and without donor bone marrow (BM) intraperitoneally into 13 to 15-day BALB/c (H2d) fetuses. Engraftment was determined by flow cytometry and quantitative polymerase chain reaction and tolerance by skin grafts and the mixed lymphocyte reaction. RESULTS: At 1-month posttransplant, mice that received BM+pDC showed a higher degree of engraftment (29+/-46%) than mice that received pDC-enriched cells or BM cells alone (0.11+/-0.70% and 1.71+/-1.66%, respectively, P<0.001). However, 5/19 recipients of BM+pDC died within 6 weeks; 4/5 had significant donor cell engraftment in blood and/or tissues. Also, these mice had evidence of graft-versus-host disease (GVHD). Two mice out of 15 long-term survivors in the BM+pDC group had virtually complete replacement of host with donor hematopoietic cells. Skin grafts and mixed lymphocyte reaction studies showed no durable tolerance induction other than in the two fully engrafted recipients of BM+pDC. CONCLUSIONS: These results suggest that donor pDC, along with donor BM, can have a significant impact on engraftment of MHC-mismatched donor cells associated with an increased incidence of GVHD. However, marrow-derived pDC do not result in an increase in tolerance induction in utero even when microchimerism is present.

Kidney morcellation in laparoscopic nephrectomy for tumor: recommendations for specimen sampling and pathologic tumor staging.

Laparoscopic nephrectomy is a novel approach for small renal tumors in selected patients; however, removal of the kidney through the small laparoscopic abdominal wall incision site requires the kidney to be morcellated into small fragments while still in situ. Morcellation presents two problems for the pathologist. First, guidelines for optimal sampling of morcellated fragments have not been described. Second, morcellation precludes complete pTNM tumor staging, in particular, tumor size, margins, and renal vein involvement. Based on our initial experience with 23 laparoscopic nephrectomies/nephroureterectomies (13 clinically suspected neoplasms, confirmed pathologically as renal cell carcinoma [RCC, n = 7], urothelial carcinoma of the renal pelvis [n = 3], angiomyolipoma [n = 1], and cystic nephroma [n = 1], and 10 clinically benign entities) and a conservative statistical model, we present a decision analysis model of various specimen sampling protocols that optimize cost, labor, or time to diagnosis (single vs sequential sampling). Using the tumor-to-kidney volume ratio (TKR), calculated from preoperative radiologic imaging and specimen gross weight, several specimen sampling algorithms were compared. For the average situation in which TKR is > or =0.15, the algorithm that most significantly optimizes cost and labor is one that initially samples 5% of the morcellated specimen. However, additional sampling may be required in one fourth of the cases. The optimal amount of sampled tissue may indeed be less than 5% because this assumes no suspicious tissue is grossly visible and in all our cases of RCC grossly visible tumor was identified. Additional nomograms for a spectrum of TKR, sampling success, and cost are presented to allow pathologists their own discretion in determining optimal sampling of the morcellated kidney. Tumor staging is severely limited by morcellation. Tumor size, renal capsule involvement, and renal vein involvement cannot be fully pathologically evaluated for RCC, whereas invasion cannot be definitively assessed for urothelial carcinoma of the renal pelvis. Knowledge of the radiologic features (lesion size, capsule, and vein involvement) is important in sampling and staging morcellated kidneys removed laparoscopically.

Clinical course and biochemistry of sialuria.

Sialuria is a rare inborn error of metabolism in which excessive free sialic acid (N-acetylneuraminic acid, NeuAc) is synthesized. A defect in the feedback inhibition of UDP-N-acetylglucosamine (UDP-GlcNAc) 2-epimerase by the end-product of the sialic acid synthetic pathway, CMP-NeuAc, is the mechanism underlying this overproduction. Recent evidence suggests that sialuria is an autosomal dominant disorder. Only five patients have been documented to have such an enzymatic defect. We report a longitudinal study of one of the original sialuria patients, to age 11 years. Although he has coarse features and massive hepatomegaly, he has shown normal growth and relatively normal development. Pulmonary function testing showed minimal small airway obstruction. At 11 years, he developed intermittent abdominal pain and transient transaminase elevation above his baseline. Sialuria should be considered in the differential diagnosis of a patient with a phenotype suggestive of a mucopolysaccharidosis or oligosaccharidosis in the absence of developmental regression or prominent dysostosis multiplex. We recommend close monitoring of liver and pulmonary function in sialuria patients.

Liver transplantation for hepatocellular carcinoma: expansion of the tumor size limits does not adversely impact survival.

The precise staging of hepatocellular carcinoma (HCC) based on the size and number of lesions that predict recurrence after orthotopic liver transplantation (OLT) has not been clearly established. We therefore analyzed the outcome of 70 consecutive patients with cirrhosis and HCC who underwent OLT over a 12-year period at our institution. Pathologic tumor staging of the explanted liver was based on the American Tumor Study Group modified Tumor-Node-Metastases (TNM) Staging Classification. Tumor recurrence occurred in 11.4% of patients after OLT. The Kaplan-Meier survival rates at 1 and 5 years were 91.3% and 72.4%, respectively, for patients with pT1 or pT2 HCC; and 82.4% and 74.1%, respectively, for pT3 tumors (P =.87). Patients with pT4 tumors, however, had a significantly worse 1-year survival of 33.3% (P =.0001). An alpha-fetoprotein (AFP) level > 1,000 ng/mL, total tumor diameter > 8 cm, age > or = 55 years and poorly differentiated histologic grade were also significant predictors for reduced survival in univariate analysis. Only pT4 stage and total tumor diameter remained statistically significant in multivariate analysis. Patients with HCC meeting the following criteria: solitary tumor < or = 6.5 cm, or < or = 3 nodules with the largest lesion < or = 4.5 cm and total tumor diameter < or = 8 cm, had survival rates of 90% and 75.2%, at 1 and 5 years, respectively, after OLT versus a 50% 1-year survival for patients with tumors exceeding these limits (P =.0005). We conclude that the current criteria for OLT based on tumor size may be modestly expanded while still preserving excellent survival after OLT.

An early lesion in hepatic carcinogenesis: loss of heterozygosity in human cirrhotic livers and dysplastic nodules at the 1p36-p34 region.

Loss of heterozygosity (LOH) of chromosome 1 has been suggested, by karyotyping, to be an initial episode in human hepatocarcinogenesis. However, this alteration has not yet been investigated in cirrhotic nodules (CNs) or dysplastic nodules (DNs). In an initial study from explanted or resected cirrhotic livers, LOH in 1p36-p32 was examined in 31 hepatocellular carcinomas (HCCs), 25 low-grade dysplastic nodules (LGDNs), and 24 high-grade dysplastic nodules (HGDNs). In HCCs, LOH was detected most frequently at loci D1S2843 (1p36.1) (28.6%), D1S513 (1p34.3) (29.2%), and MYCL1 (1p34.1) (28.6%). In HGDN and LGDN, LOH incidences at D1S513 were 11.1% and 13.6%, respectively. To further refine those results and to determine sequential relationships among CN, DN, and HCC, LOH was next studied in an additional 53 HCCs, 56 HGDNs, 30 LGDNs, and 215 CNs from 11 explanted human cirrhotic livers, including 30 "nodule-in-nodule" lesions. Seven markers between D1S2843 (1p36.12) and MYCL1 (1p34.1), and 1 each at D1S484 (1q24.1), IGF2R-3 (6q26), and TP53 (17p13.1) were used. LOH at D1S2843 and D1S513 was detected in HCCs (20.4% and 23.5%, respectively), HGDNs (7.7% and 18.5%), LGDNs (13.6% and 6.9%), and CNs surrounding either HCCs or DNs (7.4% and 8.3%). These results demonstrate that LOH at D1S2843 and D1S513 are early events in human liver carcinogenesis. Data from CN surrounding either HCCs or DN, and also nodule-in-nodule lesions, provide evidence supporting a CN-->DN-->HCC progression. Different deletion patterns from multiple HCCs and DNs suggest independent origins for carcinogenesis in the same individual.

Activation of the Met receptor by cell attachment induces and sustains hepatocellular carcinomas in transgenic mice.

Overexpression is the most common abnormality of receptor tyrosine kinases (RTKs) in human tumors. It is presumed that overexpression leads to constitutive activation of RTKs, but the mechanism of that activation has been uncertain. Here we show that overexpression of the Met RTK allows activation of the receptor by cell attachment and that this form of activation can be tumorigenic. Transgenic mice that overexpressed Met in hepatocytes developed hepatocellular carcinoma (HCC), one of the human tumors in which Met has been implicated previously. The tumorigenic Met was activated by cell attachment rather than by ligand. Inactivation of the transgene led to regression of even highly advanced tumors, apparently mediated by apoptosis and cessation of cellular proliferation. These results reveal a previously unappreciated mechanism by which the tumorigenic action of RTKs can be mediated, provide evidence that Met may play a role in both the genesis and maintenance of HCC, and suggest that Met may be a beneficial therapeutic target in tumors that overexpress the receptor.

Altered distribution of beta-catenin, and its binding proteins E-cadherin and APC, in ulcerative colitis-related colorectal cancers.

The beta-catenin pathway plays a central role in transcriptional signaling and cell-cell interactions in colonic epithelium. Alterations of the expression of beta-catenin, and its binding partners E-cadherin and the adenomatous polyposis coli protein (APC), are frequent events in sporadic colorectal cancer. Ulcerative colitis (UC)-related cancers originate in a field of chronic inflammation and therefore may have different alterations in the beta-catenin pathway than sporadic cancers. To test this hypothesis, expression and subcellular localization of beta-catenin, E-cadherin, and APC were detected by immunohistochemistry in paraffin sections from 33 UC-related and 42 sporadic colorectal cancers. Although beta-catenin and E-cadherin expression were predominantly limited to the lateral cell membrane in normal colonic epithelium, both tumor groups showed an overall shift from membranous to cytoplasmic expression for these proteins. An increase in nuclear localization of beta-catenin and a decrease in cytoplasmic APC expression also were seen in both cancer groups compared with normal epithelium. Abnormal beta-catenin expression was more closely linked to E-cadherin alterations in UC-related cancers than in sporadic cancers. In contrast, abnormal beta-catenin expression was more closely linked to APC alterations in sporadic cancers than in UC-related cancers. These data suggest that alterations of the beta-catenin pathway are important in both UC-related and sporadic colorectal cancers. However, differences in the expression patterns of beta-catenin, E-cadherin, and APC between UC-related and sporadic colorectal cancers suggest that the specific alterations in this pathway may differ in these two cancer groups.

Severity of iron overload in patients with sickle cell disease receiving chronic red blood cell transfusion therapy.

Chronic transfusion therapy is being used more frequently to prevent and treat the complications of sickle cell disease. Previous studies have shown that the iron overload that results from such therapy in other patient populations is associated with significant morbidity and mortality. In this study we examined the extent of iron overload as well as the presence of liver injury and the predictive value of ferritin in estimating iron overload in children with sickle cell disease who receive chronic red blood cell transfusions. A poor correlation was observed between serum ferritin and the quantitative iron on liver biopsy (mean 13.68 +/- 6.64 mg/g dry weight; R = 0.350, P =.142). Quantitative iron was highly correlated with the months of transfusion (R = 0.795, P <.001), but serum ferritin at biopsy did not correlate with months of transfusion (R = 0.308, P =.200). Sixteen patients had abnormal biopsies showing mild to moderate changes on evaluation of inflammation or fibrosis. Liver iron was correlated with fibrosis score (R = 0.50, P =.042). No complications were associated with the liver biopsy. Our data suggest that, in patients with sickle cell disease, ferritin is a poor marker for accurately assessing iron overload and should not be used to direct long-term chelation therapy. Despite high levels of liver iron, the associated liver injury was not severe.

HCV-related fibrosis progression following liver transplantation: increase in recent years.

BACKGROUND/AIMS: The natural history and predictors of HCV-related disease severity post-transplantation are uncertain. The aims of this study were to define the natural history of post-transplantation HCV infection by assessing the rate of fibrosis progression, to determine if the post-transplantation natural history differs from that observed pre-transplantation, and to identify predictors of post-transplantation disease progression. METHODS: Post-transplantation biopsies (mean: 3+/-1.6/patient) from 284 patients were scored according to histologic stage, using the method of Desmet et al. Change in fibrosis score (fibrosis progression/year) post-transplantation was used as the primary outcome. Predictors analyzed included viral factors (genotype and viral load at transplantation), patient demographics, year of transplantation, country of transplantation, pre-transplantation fibrosis progression, immunosuppression and laboratory data. RESULTS: There was a linear association between change in fibrosis score and time from transplantation, with a median rate of fibrosis progression per year of 0.3 (0.004-2.19/year). Using parametric time-to-event analysis, the expected median duration to cirrhosis was 10 years. The rate of post-transplantation fibrosis progression was significantly higher than pre-transplantation (0.2/year (0.09-0.8) p<0.0001), and higher in Spanish than US centers (0.48 (0.01-2.19) vs 0.28 (0.004-2.08); p=0.09) despite similar progression rates prior to transplantation. Variables independently associated with post-transplantation progression included year of transplantation (p=0.0001), race (p=0.02), number of methyl-prednisolone boluses (p=0.03), and HCV RNA levels at transplantation (p=0.01). CONCLUSIONS: HCV-related disease progression is accelerated in immunocompromised compared to immunocompetent patients, with a progressive increase in patients who have recently undergone liver transplantation. Changes in patient management post-transplantation over time and between transplant centers may account for the increase in fibrosis progression observed in recent years.

Utility of CD34 reactivity in evaluating focal nodular hepatocellular lesions sampled by fine needle aspiration biopsy.

OBJECTIVE: To determine the patterns of CD34 reactivity in hepatocellular adenoma and focal nodular hyperplasia and to evaluate the utility of CD34 reactivity in the diagnosis of hepatocellular carcinoma. STUDY DESIGN: Seventeen cases of well-differentiated hepatocellular carcinoma, 14 cases of cirrhosis, 9 cases of focal nodular hyperplasia and 7 cases of hepatocellular adenoma were stained with immunoperoxidase antibodies to CD34. The slides were scored according to the degree of lesional reactivity. RESULTS: Fourteen of 17 cell blocks with hepatocellular carcinoma showed unequivocal sinusoidal or peripheral reactivity for CD34. Five of seven cases of hepatocellular adenoma and four of nine cases of focal nodular hyperplasia showed > 50% sinusoidal reactivity for CD34. All 14 cases of cirrhosis showed peripheral to no sinusoidal reactivity. CONCLUSION: CD34 reactivity in a diffuse sinusoidal pattern can be helpful in the diagnosis of hepatocellular carcinoma. However, consideration should be given to the possibility of hepatocellular adenoma and focal nodular hyperplasia, which can also exhibit significant diffuse CD34 reactivity. In these cases, a reticulin stain may be helpful with the differential diagnosis.