Congenital Myenteric Hypoganglionosis.

Congenital myenteric hypoganglionosis is a rare developmental disorder characterized clinically by severe and persistent neonatal intestinal pseudoobstruction. The diagnosis is established by the prevalence of small myenteric ganglia composed of closely spaced ganglion cells with sparse surrounding neuropil. In practice, the diagnosis entails familiarity with the normal appearance of myenteric ganglia in young infants and the ability to confidently recognize significant deviations in ganglion size and morphology. We review clinical, histologic, and immunohistochemical findings from 12 patients with congenital myenteric hypoganglionosis in comparison with similar data from age-matched controls and clearly delineate the diagnostic features of the condition. Practical guidelines are provided to assist surgical pathologists, who are likely to encounter this condition only infrequently. The diagnosis typically requires full-thickness intestinal biopsy as the abnormality is confined to the myenteric plexus in many patients. Immunohistochemistry for Hu C/D may be used to confirm hypoganglionosis. Reduced staining for calretinin and NeuN implicates a selective deficiency of intrinsic primary afferent neurons in this disease.

Chromosomal microarray analysis of benign mesenchymal tumors with RB1 deletion.

Spindle cell lipomas/pleomorphic lipomas, mammary-type myofibroblastomas, and cellular angiofibromas are benign mesenchymal tumors that demonstrate histologically overlapping features but with varying anatomic locations and an uncertain etiologic relationship. These tumors have also been found to have an overlapping molecular profile with shared 13q14 deletions, which is the location of the tumor suppressor gene RB1 that encodes the retinoblastoma protein. Molecular studies thus far have largely focused on the RB1 locus, using primarily immunohistochemistry and fluorescence in situ hybridization to characterize RB1 status. However, further characterization of the molecular profile of these lesions, including genome-wide copy number variation, remains to be well defined. The goal of this study is to further characterize the specific RB1 deletions seen in spindle cell lipomas/pleomorphic lipomas, cellular angiofibromas, and mammary-type myofibroblastomas as well as to evaluate these neoplasms for additional molecular abnormalities using the OncoScan™ CNV Plus Assay, which is used for clinical use as a whole-genome copy number microarray-based assay. Ten of eleven cases demonstrated deletion of the RB1 gene with varying deletion size and breakpoints. The majority of additional genetic alterations were chromosomal losses and loss of heterozygosity with rare chromosomal gains. Although only a small subset of mesenchymal neoplasms was evaluated, the principle of creating a novel pairing of the molecular method with the tumor type represents a promising avenue for further study in a variety of tumors.

NF-κB upregulates glutamine-fructose-6-phosphate transaminase 2 to promote migration in non-small cell lung cancer.

BACKGROUND: Epithelial-to-mesenchymal transition (EMT) results in changes that promote de-differentiation, migration, and invasion in non-small cell lung cancer (NSCLC). While it is recognized that EMT promotes altered energy utilization, identification of metabolic pathways that link EMT with cancer progression is needed. Work presented here indicates that mesenchymal NSCLC upregulates glutamine-fructose-6-phosphate transaminase 2 (GFPT2). GFPT2 is the rate-limiting enzyme in the synthesis of uridine diphosphate N-acetylglucosamine (UDP-GlcNAc). UDP-GlcNAc is the obligate activator of O-linked N-acetylglucosamine transferase (OGT). METHODS: Analysis of our transcriptomic data indicates that GFPT2 is one of the most significantly upregulated metabolic genes in mesenchymal NSCLC. Ectopic GFPT2 expression, as well as gene silencing strategies were used to determine the importance of this metabolic enzyme in regulating EMT-driven processes of cell motility and invasion. RESULTS: Our work demonstrates that GFPT2 is transcriptionally upregulated by NF-κB and repressed by the NAD+-dependent deacetylase SIRT6. Depletion of GFPT2 expression in NSCLC highlights its importance in regulating cell migration and invasion during EMT. CONCLUSIONS: Consistent with GFPT2 promoting cancer progression, we find that elevated GFPT2 expression correlates with poor clinical outcome in NSCLC. Modulation of GFPT2 activity offers a potentially important therapeutic target to combat NSCLC disease progression.

The Undergraduate Training in Genomics (UTRIG) Initiative: early & active training for physicians in the genomic medicine era.

Genomic medicine is transforming patient care. However, the speed of development has left a knowledge gap between discovery and effective implementation into clinical practice. Since 2010, the Training Residents in Genomics (TRIG) Working Group has found success in building a rigorous genomics curriculum with implementation tools aimed at pathology residents in postgraduate training years 1-4. Based on the TRIG model, the interprofessional Undergraduate Training in Genomics (UTRIG) Working Group was formed. Under the aegis of the Undergraduate Medical Educators Section of the Association of Pathology Chairs and representation from nine additional professional societies, UTRIG's collaborative goal is building medical student genomic literacy through development of a ready-to-use genomics curriculum. Key elements to the UTRIG curriculum are expert consensus-driven objectives, active learning methods, rigorous assessment and integration.

Cyclin D1 expression and polysomy in lymphocyte-predominant cells of nodular lymphocyte-predominant Hodgkin lymphoma.

Cyclin D1 protein expression in lymphocytes is classically associated with mantle cell lymphoma. Although increasingly recognized in other lymphoproliferative disorders, cyclin D1 expression and CCND1 gene abnormalities have not been well studied in nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL). Using a double stain for CD20/cyclin D1, we quantified cyclin D1 expression in 10 cases of NLPHL and correlated those findings with SOX11 expression, CCND1 gene abnormalities, and clinical data. For comparison, we examined 5 cases of T cell-/histiocyte-rich large B-cell lymphoma (THRLBCL). All cases of NLPHL stained for cyclin D1 showed at least rare positivity in lymphocyte-predominant (LP) cells. In 4 cases, at least 20% of LP cells were positive for CD20/cyclin D1. Neither SOX11 expression nor CCND1 gene rearrangement was found in any of the cases, but fluorescence in situ hybridization showed a proportion of the large cells with 3 to 4 copies of nonfused IGH and CCND1 signals or 3 intact CCND1 break-apart signals. Further study with CCND1/CEP11 showed polysomy in 6 of 9 cases with cyclin D1 expression and 5 of 16 NLPHL not examined for cyclin D1. Two of 5 cases of THRLBCL showed rare positive staining for CD20/cyclin D1; 1 case showed polysomy with CCND1/CEP11. Results show that cyclin D1 may be expressed in LP cells without SOX11 expression or CCND1 translocation. Polysomy with increased copies of CCND1 may account for cyclin D1 expression in some cases. Cyclin D1 expression is not useful for distinguishing NLPHL from THRLBCL and has no apparent clinical significance in NLPHL.

Comparison of Histological Characteristics of Acellular Dermal Matrix Capsules to Surrounding Breast Capsules in Acellular Dermal Matrix-Assisted Breast Reconstruction.

INTRODUCTION: Despite the widespread adaptation of acellular dermal matrix (ADM) to breast reconstruction, we are just now exploring how these materials integrate and perform in vivo. The goal of this study was to compare the histological characteristics between expander capsules to an area without the ADM. METHODS: Women undergoing implant-based breast reconstruction at the University of Virginia Health System using a decellularized regenerative dermal matrix were enrolled in this prospective, evaluator-blinded, institutional review board-approved study. Twenty-four non-ADM and 24 ADM breast capsule biopsy specimens were collected from 15 women and analyzed for the histological parameters of inflammation, vascular proliferation, capsule fibrosis, foreign body giant cell inflammatory reaction, and myofibroblasts using a previously described semiquantitative scoring system. The pathologist evaluating the specimens was blinded to the tissue source and biopsy location. RESULTS: There was significantly less inflammation and fewer myofibroblasts in the ADM capsule biopsy samples compared with the no-ADM capsule biopsy samples (inflammation: ADM, 0.83; no-ADM, 1.83; P = 0.001; myofibroblasts: ADM, 0.79; no-ADM, 1.46; P = 0.024). Significantly less vascular proliferation in the ADM samples was seen compared with the no-ADM samples (ADM, 0.75; no-ADM, 1.42; P = 0.036). No statistical difference in the presence of an inflammatory capsule was observed in the no-ADM biopsy samples compared with the ADM capsule biopsy samples (P = 0.060). CONCLUSIONS: When used for staged breast reconstruction, this unique, sterile ADM seems to induce less inflammation. Moreover, the significantly decreased presence of myofibroblasts in this material supports the observed clinical findings of decreased capsular contracture in ADM-assisted breast reconstruction.

Epiphyseal presentation of non-Hodgkin's lymphoma of bone in two pediatric patients--one with primary lymphoma of bone.

We report two children with lymphoma of bone centered in the distal femoral epiphysis who presented with knee pain. Radiographs, magnetic resonance imaging (MRI) and computed tomography (CT) were performed on both patients prior to biopsy. Following biopsy, both patients had fluorodeoxyglucose ((18) F-FDG) positron emission tomography/CT (PET/CT) and whole-body technetium-99m (Tc-99m) scintigraphy performed for staging. One patient met the criteria for primary lymphoma of bone. One patient did not meet the criteria for primary lymphoma of bone because of PET uptake in a popliteal, external iliac and possibly lower abdominal node. Both patients responded well to chemotherapy and are disease free more than 7 years after diagnosis. While an epiphyseal presentation of lymphoma of bone is rare, the efficacy of treatment and the compromised outcome associated with diffuse spread of the disease make early recognition by clinicians important. We present these two cases to increase awareness of the disease and to have clinicians consider it in the differential diagnosis of adolescent epiphyseal lesions.

Morphology in conjunction with immunohistochemistry is sufficient for the diagnosis of mammary analogue secretory carcinoma.

The recently described mammary analogue secretory carcinoma (MASC) is a low-grade salivary gland malignancy that harbors the recurrent cytogenetic abnormality t(12;15) (p13;q25) ETV6-NTRK3. Confirmation of this is currently considered the gold standard for diagnosis. Some have postulated that morphology together with supporting immunohistochemistry is sufficient to diagnose MASC. In this study we retrospectively review a series of 19 MASCs diagnosed based on histology in conjunction with immunohistochemistry; subsequently we performed in situ hybridization using an ETV6 break-apart probe. Immunohistochemistry for S100 protein and mammaglobin as well as fluorescence in situ hybridization using the Vysis ETV6 Dual Color Break-Apart FISH Probe Kit were performed on all cases. The 19 cases were from 12 females and 7 males with ages ranging from 16 to 76 years (mean = 45 years). Sixteen cases were from the parotid gland, 1 case was from a periparotid lymph node and 2 cases were from the submandibular gland. All 19 cases demonstrated moderate to strong expression of S100 protein. Eighteen cases demonstrated strong, diffuse expression of mammaglobin, while one case had only rare tumor cells that strongly expressed mammaglobin. Eighteen of 19 cases (95 %) demonstrated the ETV6 rearrangement by fluorescence in situ hybridization. Given that morphology together with immunohistochemistry is highly correlated with the ETV6 gene rearrangement, we conclude that molecular confirmation is not required to diagnose MASC.

Lineage of origin in rhabdomyosarcoma informs pharmacological response.

Lineage or cell of origin of cancers is often unknown and thus is not a consideration in therapeutic approaches. Alveolar rhabdomyosarcoma (aRMS) is an aggressive childhood cancer for which the cell of origin remains debated. We used conditional genetic mouse models of aRMS to activate the pathognomonic Pax3:Foxo1 fusion oncogene and inactivate p53 in several stages of prenatal and postnatal muscle development. We reveal that lineage of origin significantly influences tumor histomorphology and sensitivity to targeted therapeutics. Furthermore, we uncovered differential transcriptional regulation of the Pax3:Foxo1 locus by tumor lineage of origin, which led us to identify the histone deacetylase inhibitor entinostat as a pharmacological agent for the potential conversion of Pax3:Foxo1-positive aRMS to a state akin to fusion-negative RMS through direct transcriptional suppression of Pax3:Foxo1.

Identification of renin progenitors in the mouse bone marrow that give rise to B-cell leukaemia.

The cell of origin and triggering events for leukaemia are mostly unknown. Here we show that the bone marrow contains a progenitor that expresses renin throughout development and possesses a B-lymphocyte pedigree. This cell requires RBP-J to differentiate. Deletion of RBP-J in these renin-expressing progenitors enriches the precursor B-cell gene programme and constrains lymphocyte differentiation, facilitated by H3K4me3 activating marks in genes that control the pre-B stage. Mutant cells undergo neoplastic transformation, and mice develop a highly penetrant B-cell leukaemia with multi-organ infiltration and early death. These renin-expressing cells appear uniquely vulnerable as other conditional models of RBP-J deletion do not result in leukaemia. The discovery of these unique renin progenitors in the bone marrow and the model of leukaemia described herein may enhance our understanding of normal and neoplastic haematopoiesis.

DICER1 mutations in childhood cystic nephroma and its relationship to DICER1-renal sarcoma.

The pathogenesis of cystic nephroma of the kidney has interested pathologists for over 50 years. Emerging from its initial designation as a type of unilateral multilocular cyst, cystic nephroma has been considered as either a developmental abnormality or a neoplasm or both. Many have viewed cystic nephroma as the benign end of the pathologic spectrum with cystic partially differentiated nephroblastoma and Wilms tumor, whereas others have considered it a mixed epithelial and stromal tumor. We hypothesize that cystic nephroma, like the pleuropulmonary blastoma in the lung, represents a spectrum of abnormal renal organogenesis with risk for malignant transformation. Here we studied DICER1 mutations in a cohort of 20 cystic nephromas and 6 cystic partially differentiated nephroblastomas, selected independently of a familial association with pleuropulmonary blastoma and describe four cases of sarcoma arising in cystic nephroma, which have a similarity to the solid areas of type II or III pleuropulmonary blastoma. The genetic analyses presented here confirm that DICER1 mutations are the major genetic event in the development of cystic nephroma. Further, cystic nephroma and pleuropulmonary blastoma have similar DICER1 loss of function and 'hotspot' missense mutation rates, which involve specific amino acids in the RNase IIIb domain. We propose an alternative pathway with the genetic pathogenesis of cystic nephroma and DICER1-renal sarcoma paralleling that of type I to type II/III malignant progression of pleuropulmonary blastoma.

EWSR1 genetic rearrangements in salivary gland tumors: a specific and very common feature of hyalinizing clear cell carcinoma.

The Ewing sarcoma breakpoint region 1 (EWSR1) is translocated in many sarcomas. Recently, its rearrangement has been described in salivary gland hyalinizing clear cell carcinomas (HCCCs) and in a subset of soft tissue myoepitheliomas. This study examines the presence of the EWSR1 rearrangement in a variety of salivary gland lesions including classic myoepitheliomas and HCCCs. Using a tissue microarray and whole-mount sections, fluorescence in situ hybridization (FISH) was performed on a variety of salivary gland lesions including HCCCs. The EWSR1 rearrangement was detected in 87% of HCCCs (13 of 15); all other salivary gland lesions including classic myoepitheliomas had intact EWSR1. Patients with HCCCs with rearranged EWSR1 included 1 man, 10 women, and 2 of unknown sex. Ages ranged from 35 to 83 years; the tumor size ranged from 0.8 to 5.5 cm, and the involved locations included: palate (2), base of the tongue (2), mandible (2), submandibular gland (2), lip (1), floor of the mouth (1), sublingual gland (1), inner cheek (1), and nasopharynx (1). All HCCCs were composed of sheets and nests of monotonous cells with clear cytoplasm within a hyalinized stroma. All tested cases were immunoreactive with antibodies to p63 and were nonreactive with antibodies to more conventional myoepithelial antigens (e.g., smooth muscle actin and S100 protein). These findings show that the EWSR1 rearrangement is almost a defining feature of HCCCs and also confirm that classic salivary gland myoepitheliomas are distinct from these tumors and do not share a pathogenetic relationship with their soft tissue counterparts.

Spindle cell rhabdomyosarcoma of the neck with t(6;8) translocation: report of a case and literature review.

Spindle cell rhabdomyosarcoma is an uncommon subtype of embryonal rhabdomyosarcoma. Found almost exclusively in children, these tumors are classically located in the paratesticular and head and neck regions. Morphologically these lesions can resemble several other benign or malignant soft-tissue spindle cell lesions, especially smooth muscle or myofibroblastic tumors, and thus immunohistochemical staining is often needed to prove skeletal muscle differentiation. Although there is extensive literature reporting the genetics of embryonal rhabdomyosarcoma, little is reported specific to the spindle cell subtype. Below we present the case of a 7-month-old male presenting with a large posterior neck mass that was diagnosed as spindle cell rhabdomyosarcoma. Karyotype evaluation revealed a t(6;8) (p12;q11.2) chromosomal translocation within the lesion. We review the histologic and immunohistochemical diagnosis of these tumors and discuss the genetics of rhabdomyoscarcomas.

Melanotic xp11.2 neoplasm of the ovary: report of a unique case.

We describe a primary ovarian neoplasm, occurring in a 15-year-old female patient, with morphologic, immunohistochemical, and molecular genetic features identical to those of the very rare tumors of the kidney previously described as "melanotic Xp11 translocation renal cancer." This represents, to the best of our knowledge, the first report of a melanotic Xp11 translocation-associated neoplasm arising outside of the kidney. We discuss the relationship of these rare tumors to neoplasms showing perivascular epithelioid cell differentiation, in particular those showing TFE3 rearrangements.

Molecular Pathology of Sarcoma.

The rapid growth of tissue-based molecular pathology has changed the practice of the surgical pathologist signing out soft tissue tumors. This information is presented in a practical and succinct manner focusing on clinically validated findings that have diagnostic or therapeutic relevance. The approach is morphologically based and focuses on differential diagnoses and clinical scenarios. Molecular techniques can be an invaluable ancillary tool.

Evasion mechanisms to Igf1r inhibition in rhabdomyosarcoma.

Inhibition of the insulin-like growth factor 1 receptor (Igf1r) is an approach being taken in clinical trials to overcome the dismal outcome for metastatic alveolar rhabdomyosarcoma (ARMS), an aggressive muscle cancer of children and young adults. In our study, we address the potential mechanism(s) of Igf1r inhibitor resistance that might be anticipated for patients. Using a genetically engineered mouse model of ARMS, validated for active Igf1r signaling, we show that the prototypic Igf1r inhibitor NVP-AEW541 can inhibit cell growth and induce apoptosis in vitro in association with decreased Akt and Mapk phosphorylation. However, drug resistance in vivo is more common and is accompanied by Igf1r overexpression, Mapk reactivation, and Her2 overexpression. Her2 is found to form heterodimers with Igf1r in resistant primary tumor cell cultures, and stimulation with Igf2 leads to Her2 phosphorylation. The Her2 inhibitor lapatinib cooperates with NVP-AEW541 to reduce Igf1r phosphorylation and to inhibit cell growth even though lapatinib alone has little effect on growth. These results point to the potential therapeutic importance of simultaneous targeting of Igf1r and Her2 to abrogate resistance.

Hepatocyte cytokeratin 7 expression in chronic allograft rejection.

We examined hepatocyte cytokeratin 7 (CK7) expression in chronic allograft rejection (CR), a ductopenic condition in which this has not been systematically evaluated, in 20 patients with the clinicopathologic diagnosis of CR and age-, sex-, and native-disease-matched control subjects. We also studied baseline biopsy specimens from both groups. Three pathologists independently reviewed H&E- and CK7-stained sections, counting interlobular bile ducts (BDs) and portal tracts (PTs), noting the morphologic pattern of injury and scoring hepatocyte CK7 expression (0, none; 1+, rare; 2+, multifocal, predominantly periportal; 3+, extension into the lobule; 4+, diffuse). Mean BD/PT ratios and CK7 scores were calculated. The mean BD/PT ratio (0.58) and CK7 score (1.01) for the "CR, diagnostic" group were significantly different from all other group means (P < .05); no other comparisons were significant (P > .05). A CK7 score of 1 or more was observed in 9 (56%) of 16 CR specimens and in 3 (7%) of 41 remaining specimens. Hepatocyte CK7 expression is frequently noted in CR, and it would appear to reflect ductopenia. CK7 staining may be a useful diagnostic adjunct in evaluation of transplant liver biopsy specimens.

Imaging characteristics of angiomatoid fibrous histiocytoma of bone.

We present the first report of a patient with angiomatoid fibrous histiocytoma of bone in the radiology literature. This tumor initially eluded diagnosis due to its similarities with chronic hematoma and aneurysmal bone cyst. Only two cases of angiomatoid fibrous histiocytoma have been reported in the radiology literature and both of these lesions were in the soft tissues. The fairly distinctive findings in our patient of multiple large cystic chambers with fluid-fluid levels are similar to the findings in the two soft tissue case reports, suggesting that imaging may be used to suggest this specific diagnosis regardless of location, especially in the clinical setting of unexplained hematoma or anemia. Mention of this diagnosis in the radiology report may aid in the final diagnosis at pathology, because special techniques, including fluorescent in situ hybridization, must be applied in order to fully evaluate for the diagnosis.