Insights from a high-fat diet fed mouse model with a humanized liver.

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disorder worldwide and is increasing at an alarming rate. NAFLD is strongly associated with obesity and insulin resistance. The use of animal models remains a vital aspect for investigating the molecular mechanisms contributing to metabolic dysregulation and facilitating novel drug target identification. However, some differences exist between mouse and human hepatocyte physiology. Recently, chimeric mice with human liver have been generated, representing a step forward in the development of animal models relevant to human disease. Here we explored the feasibility of using one of these models (cDNA-uPA/SCID) to recapitulate obesity, insulin resistance and NAFLD upon feeding a Western-style diet. Furthermore, given the importance of a proper control diet, we first evaluated whether there are differences between feeding a purified ingredient control diet that matches the composition of the high-fat diet and feeding a grain-based chow diet. We show that mice fed chow have a higher food intake and fed glucose levels than mice that received a low-fat purified ingredient diet, suggesting that the last one represents a better control diet. Upon feeding a high-fat or matched ingredient control diet for 12 weeks, cDNA-uPA/SCID chimeric mice developed extensive macrovesicular steatosis, a feature previously associated with reduced growth hormone action. However, mice were resistant to diet-induced obesity and remained glucose tolerant. Genetic background is fundamental for the development of obesity and insulin resistance. Our data suggests that using a background that favors the development of these traits, such as C57BL/6, may be necessary to establish a humanized mouse model of NAFLD exhibiting the metabolic dysfunction associated with obesity.

Central Nervous System Whipple Disease Presenting as Hypersomnolence.

Whipple disease (WD) is a rare systemic infection caused by Tropheryma whipplei (T. whipplei). Its clinical features are broad, and atypical clinical patterns such as the involvement of the heart, lungs, or the central nervous system (CNS) can occur. We report a case of a 58-year-old man who had been previously diagnosed with classic WD; he was evaluated for functional decline, extreme somnolence, and recurrent admissions for hydrocephalus. The patient was diagnosed with a neurologic relapse of WD after a positive T. whipplei polymerase chain reaction (PCR) from a cerebral spinal fluid (CSF) sample. He was successfully treated with IV ceftriaxone followed by oral trimethoprim-sulfamethoxazole (TMP-SMX). In classic WD, the CNS symptoms usually present in the late phase of the disease or in the form of relapse, especially after an inadequate treatment course. This case highlights the importance of considering CNS involvement in WD when a patient with a previous history of classic WD presents with hypersomnolence, hydrocephalus, or other neurologic symptoms.

Recurrent KRAS mutations are early events in the development of papillary renal neoplasm with reverse polarity.

We evaluated the clinicopathologic and molecular characteristics of mostly incidentally detected, small, papillary renal neoplasms with reverse polarity (PRNRP). The cohort comprised 50 PRNRP from 46 patients, divided into 2 groups. The clinically undetected (<5 mm) neoplasms (n = 34; 68%) had a median size of 1.1 mm (range 0.2-4.3 mm; mean 1.4 mm), and the clinically detected (≥5 mm) neoplasms (n = 16; 32%) which had a median size of 13 mm (range 9-30 mm; mean 16 mm). Neoplasms were positive for GATA3 (n = 47; 100%) and L1CAM (n = 34/38; 89%) and were negative for vimentin (n = 0/44; 0%) and, to a lesser extent, AMACR [(n = 12/46; 26%; weak = 9, weak/moderate = 3)]. KRAS mutations were found in 44% (n = 15/34) of the clinically undetected PRNRP and 88% of the clinically detected PRNRP (n = 14/16). The two clinically detected PRNRP with wild-type KRAS gene were markedly cystic and contained microscopic intracystic tumors. In the clinically undetected PRNRP, the detected KRAS mutations rate was higher in those measuring ≥1 mm vs <1 mm [n = 14/19 (74%) vs n = 1/15 (7%)]. Overall, the KRAS mutations were present in exon 2-codon 12: c.35 G > T (n = 21), c.34 G > T (n = 3), c.35 G > A (n = 2), c.34 G > C (n = 2) resulting in p.Gly12Val, p. Gly12Asp, p.Gly12Cys and p.Gly12Arg, respectively. One PRNRP had a G12A/V/D complex mutation. Twenty-six PRNRP were concurrently present with other tumors of different histologic subtypes in the ipsilateral kidney; molecular testing of 8 of the latter showed wild-type KRAS gene despite the presence of KRAS mutations in 5 concurrent PRNRP. On follow up, no adverse pathologic events were seen (range 1-160 months; mean 44 months). In conclusion, the presence of KRAS mutations in small, clinically undetected PRNRP provides a unique finding to this entity and supports its being an early event in the development of these neoplasms.

Lymphoproliferative Neoplasms With Plasmablastic Morphology.

CONTEXT.­: Plasmablastic morphology can be seen in several uncommon lymphoproliferative neoplasms. Sometimes it is difficult to distinguish these neoplasms from each other. OBJECTIVE.­: To review the current understanding of major lymphoproliferative neoplasms with plasmablastic morphology; summarize the clinical, morphologic, immunophenotypic, cytogenetic, and molecular characteristics of each disease entity; and highlight a practical approach for differential diagnosis. DATA SOURCES.­: Peer-reviewed medical literature and the authors' personal experience. CONCLUSIONS.­: Plasmablastic lymphoma; plasmablastic myeloma; primary effusion lymphoma; human herpesvirus 8-positive diffuse large B-cell lymphoma, not otherwise specified; and anaplastic lymphoma kinase (ALK)-positive large B-cell lymphoma are major lymphoproliferative neoplasms with plasmablastic morphology. These neoplasms share many common morphologic and immunophenotypic characteristics. Definitive diagnosis requires a thorough understanding of disease phenotype and diagnostic criteria of each category. Recognition of expression pattern of Epstein-Barr virus-encoded small RNA, human herpesvirus 8, and ALK in these neoplasms is critical for diagnosis in cases with typical presentation. Additional ancillary studies and clinical findings may help in difficult cases.

Electronic Health Records and Genomics: Perspectives from the Association for Molecular Pathology Electronic Health Record (EHR) Interoperability for Clinical Genomics Data Working Group.

The use of genomics in medicine is expanding rapidly, but information systems are lagging in their ability to support genomic workflows both from the laboratory and patient-facing provider perspective. The complexity of genomic data, the lack of needed data standards, and lack of genomic fluency and functionality as well as several other factors have contributed to the gaps between genomic data generation, interoperability, and utilization. These gaps are posing significant challenges to laboratory and pathology professionals, clinicians, and patients in the ability to generate, communicate, consume, and use genomic test results. The Association for Molecular Pathology Electronic Health Record Working Group was convened to assess the challenges and opportunities and to recommend solutions on ways to resolve current problems associated with the display and use of genomic data in electronic health records.

Relapse of tagraxofusp treated blastic plasmacytoid dendritic cell neoplasm with loss of CD123 expression.

Tagraxofusp, a CD123-based-targeted immunotherapy, was recently approved to treat blastic plasmacytoid dendritic cell neoplasm (BPDCN) with excellent response. Also, a subset of BPDCN shows resistance to tagraxofusp. These resistant cases continue to express CD123, which forms the basis of the continued utility of tagraxofusp in newer combination chemotherapies to overcome resistance in BPDCN. Herein, we report a case of an elderly male with BPDCN that achieved complete remission on initial primary treatment with tagraxofusp. However, BPDCN relapsed after 1.5 years while on treatment, with loss of CD123 expression. At relapse, the neoplasm was comprehensively immunophenotyped by flow cytometry (performed on both peripheral blood and bone marrow specimen) and by immunohistochemical evaluation of the bone marrow clot section. The neoplasm at relapse was diagnostic of BPDCN with a lack of CD123 expression. This case highlights a potential limitation of current and upcoming tagraxofusp-based multidrug therapies, at least in a subset of refractory BPDCN. We believe our report will serve as a sentinel to incite future investigations involving alternate resistance mechanisms in BDPCN.

EWSR1-PATZ1 fusion renal cell carcinoma: a recurrent gene fusion characterizing thyroid-like follicular renal cell carcinoma.

Thyroid-like follicular renal cell carcinoma is an uncommon kidney tumor with no distinct molecular alteration described to date. This cohort of eight women with mean and median ages of 45 and 46 years, respectively (range 19-65 years), had unencapsulated, well-circumscribed tumors composed of tightly packed anastomosing follicle-like cysts filled with eosinophilic colloid-like material and lined by cuboidal cells with high nuclear to cytoplasmic ratios, oval to elongated nuclei with perpendicular arrangement toward the lumens, and prominent nuclear overlapping. The stroma between these was minimal with the exception of two tumors. Calcifications and necrosis were absent. Immunohistochemically, the tumors were positive for KRT19 (7/7), PAX8 (5/5), cyclin D1 (6/6), KRT7 (5/7), and AMACR (1/5; focal, weak), and were negative for WT1, TTF1 (transcription termination factor-1), and thyroglobulin. In three of three tumors tested molecularly, EWSR1-PATZ1 fusion was identified by RNA sequencing and confirmed by RT-PCR and Sanger sequencing. Over a follow-up period of 1-7 years, no evidence of recurrence or metastasis has been detected. The EWSR1-PATZ1 fusion has been recognized as a recurrent alteration in a subset of round to spindle cell sarcomas with EWSR1-non-ETS fusions (EWSR1-PATZ1 sarcoma) and in several central nervous system tumors. The finding of an EWSR1-PATZ1 fusion in all three of the thyroid-like follicular renal cell carcinomas for which sufficient tissue was available for genomic profiling provides the first distinct molecular abnormality in thyroid-like follicular renal cell carcinomas, supporting its designation as a distinct diagnostic entity.

Myeloid neoplasm with a novel cryptic PDGFRB rearrangement detected by next-generation sequencing.

Rearrangements of PDGFRB are defining cytogenetic abnormalities seen in "Myeloid/lymphoid neoplasms with eosinophilia and rearrangement of PDGFRB" and are generally evident by common cytogenetic methods. Here we present an unique case in which karyotyping and fluorescence in situ hybridization (FISH) analysis were negative, and the PDGFRB rearrangement was detected by next-generation sequencing (NGS) analysis. The patient presented with approximately one-year history of leukocytosis including neutrophilia, eosinophilia, basophilia and granulocytic left shift. Bone marrow biopsy revealed a hypercellular marrow with panmyelosis, eosinophilia and mast cell hyperplasia. Blasts were not increased. Ancillary studies revealed a normal karyotype and absence of BCR-ABL1 fusion gene. NGS identified AFAP1L1-PDGFRB fusion, which was confirmed by polymerase chain reaction amplification followed by direct Sanger sequencing. The patient was treated with imatinib and showed normalization of peripheral blood leukocytosis, which lasted for at least six months. This case highlights that cytogenetics/FISH study alone may be insufficient to detect all PDGFRB rearrangement, which is critical for the patient's management. We suggest that molecular analysis capable of detecting fusion genes should be performed in all similar cases.

Recurrent KRAS mutations in papillary renal neoplasm with reverse polarity.

We recently proposed that an epithelial renal tumor "papillary renal neoplasm with reverse polarity" represents a distinct entity. It constituted 4% of previously diagnosed papillary renal cell carcinoma at the participating institutions. Histologically, it is characterized by papillary or tubulopapillary architecture covered by a single layer of eosinophilic cells with finely granular cytoplasm and apically located nuclei. It is characteristically positive for GATA3 and L1CAM and lack vimentin and, to a lesser extent, α-methylacyl-CoA-racemase (AMACR/p504s) immunostaining. To investigate the molecular pathogenesis of these tumors, we performed targeted next-generation sequencing on ten previously reported papillary renal neoplasms with reverse polarity, followed by a targeted polymerase chain reaction analysis for KRAS mutations in a control series of 30 type 1 and 2 papillary renal cell carcinomas. KRAS missense mutations were identified in eight of ten papillary renal neoplasms with reverse polarity. These mutations were clustered in exon 2-codon 12: c.35 G > T (n = 6) or c.34 G > C (n = 2) resulting in p.Gly12Val and p.Gly12Arg alterations, respectively. One of the wild-type tumors had BRAF c.1798_1799delGTinsAG (p.Val600Arg) mutation. No KRAS mutations were identified in any of the 30 control tumors. In summary, this study supports our proposal that papillary renal neoplasm with reverse polarity is an entity distinct from papillary renal cell carcinoma and the only renal cell neoplasm to consistently harbor KRAS mutations.

Live remote digital microscopy in peripheral blood smear evaluation: Intraobserver concordance and experience.

INTRODUCTION: Peripheral blood smear (PBS) review is a routine laboratory test which requires pathologist's interpretation when abnormal indices, atypical cells, or critical findings are identified. Real-time remote digital microscopy (DM) can potentially facilitate rapid review when an on-site pathologist is not available. Herein, we assess intraobserver concordance of PBS evaluation with light microscopy (LM) and DM using VisionTek M6 robotic DM and TeamViewer imaging software. METHODS: Thirty-seven de-identified PBS slides were evaluated by five reviewers. Slides were loaded on a VisionTek M6 robotic microscope at an off-site laboratory and evaluated remotely via TeamViewer software. Reviewers recorded interpretation, time required for interpretation (in minutes), imaging quality (score 0-3), and confidence of interpretation (score 0-3). Other relevant information associated with DM evaluation was also documented. Slides were subsequently evaluated using LM after washout interval. The intraobserver variation of results for impression, digital slide quality, minutes to interpretation, and confidence of interpretation was compared between DM and LM. RESULTS: The intraobserver concordance between LM and DM was 93%, with nine discordant interpretations among 135 evaluations under each review modality, respectively. Although reviewers spent more time under DM mode (5 min/slide) than LM mode (2.5 min/slide), the reviewers felt the DM provided sufficient image quality and the confidence levels of reviewers on slide interpretation were comparable between DM (2.6/3) and LM (2.8/3). CONCLUSION: There was a high level of intraobserver concordance and comparable interpretation confidence between DM and LM. DM can be a useful methodology for off-site pathologist's review of PBS.

Consecutive epigenetically-active agent combinations act in ID1-RUNX3-TET2 and HOXA pathways for Flt3ITD+ve AML.

Co-occurrence of Flt3ITD and TET2 mutations provoke an animal model of AML by epigenetic repression of Wnt pathway antagonists, including RUNX3, and by hyperexpression of ID1, encoding Wnt agonist. These affect HOXA over-expression and treatment resistance. A comparable epigenetic phenotype was identified among adult AML patients needing novel intervention. We chose combinations of targeted agents acting on distinct effectors, at the levels of both signal transduction and chromatin remodeling, in relapsed/refractory AML's, including Flt3ITD+ve, described with a signature of repressed tumor suppressor genes, involving Wnt antagonist RUNX3, occurring along with ID1 and HOXA over-expressions. We tracked patient response to combination of Flt3/Raf inhibitor, Sorafenib, and Vorinostat, pan-histone deacetylase inhibitor, without or with added Bortezomib, in consecutive phase I trials. A striking association of rapid objective remissions (near-complete, complete responses) was noted to accompany induced early pharmacodynamic changes within patient blasts in situ, involving these effectors, significantly linking RUNX3/Wnt antagonist de-repression (80%) and ID1 downregulation (85%), to a response, also preceded by profound HOXA9 repression. Response occurred in context of concurrent TET2 mutation/hypomorphy and Flt3ITD+ve mutation (83% of complete responses). Addition of Bortezomib to the combination was vital to attainment of complete response in Flt3ITD+ve cases exhibiting such Wnt pathway dysregulation.

Signet-ring cell lymphoma: clinicopathologic, immunohistochemical, and fluorescence in situ hybridization studies of 7 cases.

CONTEXT: Signet-ring cell lymphoma (SRCL) is a rare morphologic variant of non-Hodgkin lymphoma. Although it was initially reported as a rare morphologic variant of follicular lymphoma (FL), SRCL has to date been described in most types of non-Hodgkin lymphoma, mostly as single-case reports. OBJECTIVE: To study SRCL systematically by immunohistochemical stains and fluorescent in situ hybridization analyses. DESIGN: Seven SRCL cases were stained for CD3, CD5, CD20, PAX-5, CD10, CD21, CD23, cyclin D1, BCL2, BCL6, Ki-67, and MUM-1, and were analyzed by fluorescent in situ hybridization for BCL2, BCL6, MYC, and MALT1 rearrangements. Clinical information and patient outcome were reviewed in all patients. RESULTS: The patients were 3 women and 3 men, ranging in age from 31 to 75 years (average 60.3 years). The lesions involved lymph nodes, tonsil, parotid gland, soft tissue, and breast. There were 4 FLs, 1 diffuse large B-cell lymphoma (DLBCL), 1 DLBCL with FL, and 1 DLBCL with marginal zone lymphoma. All cases had typical signet-ring cell morphology. They were positive for CD20 and BCL-2, and had low-to-intermediate Ki-67 proliferation index (10%-40%) except in the parotid DLBCL with FL (70%). BCL-6 was detected in all but 1 FL (6/7). Fluorescent in situ hybridization detected IGH/BCL2 translocation in 1 FL, increased BCL6 copy number in another FL, BCL6 rearrangement, and increased copy number of MYC and MALT1 in the DLBCL with marginal zone lymphoma. CONCLUSIONS: The FL with signet-ring cell morphology (1/5) tends to lack IGH/BCL2 translocation, and an extended immunohistochemical study is recommended for correct diagnosis and classification of SRCL.

Clinical benefit of a precision medicine based approach for guiding treatment of refractory cancers.

PATIENTS AND METHODS: Patients with metastatic solid tumors who had progressed on at least one line of standard of care therapy were referred to the Indiana University Health Precision Genomics Program. Tumor samples were submitted for DNA & RNA next-generation sequencing, fluorescence in situ hybridization, and immunohistochemistry for actionable targets. A multi-disciplinary tumor board reviewed all results. For each patient, the ratio of progression-free survival (PFS) of the genomically guided line of therapy divided by the PFS of their prior line was calculated. Patients whose PFS ratio was ≥ 1.3 were deemed to have a meaningful improvement in PFS. RESULTS: From April 2014-October 2015, 168 patients were evaluated and 101 patients achieved adequate clinical follow-up for analysis. 19 of 44 (43.2%) patients treated with genomically guided therapy attained a PFS ratio ≥ 1.3 vs. 3 of 57 (5.3%) treated with non-genomically guided therapy (p < 0.0001). Similarly, overall PFS ratios (irrespective of cutoff) were higher for patients with genomically guided therapy vs non-genomically guided therapy (p = 0.05). Further, patients treated with genomically guided therapy had a superior median PFS compared to those treated with non-genomically guided therapy (86 days vs. 49 days, p = 0.005, H.R. = 0.55, 95% C.I.:0.37-0.84). CONCLUSION: Patients with refractory metastatic cancer who receive genomically guided therapy have improved PFS ratios and longer median PFS compared to patients who do not receive genomically guided therapy.

Histiocytic Sarcoma Associated with Coombs Negative Acute Hemolytic Anemia: A Rare Presentation.

Histiocytic sarcoma (HS) rarely involves extranodal sites, such as the spleen. We report a unique pediatric case of massive splenomegaly and refractory Coombs negative hemolytic anemia (CNHA) secondary to HS. The CNHA resolved completely after an emergent splenectomy. Next generation sequencing (NGS) revealed novel ASXL1, PTPN11, KIT, and TP53 mutations, unmasking a clonal heterogeneity within the same neoplasm.

Clonal CD8+ T Lymphocytic Proliferation and Karyotypical Abnormalities in an EBV Associated Hemophagocytic Lymphohistiocytosis.

EBV associated hemophagocytic lymphohistiocytosis and EBV-positive T cell lymphoproliferative disease of childhood share many histologic and clinical features, which sometimes makes it very difficult to render a definitive diagnosis. In this report, we present a 16-year-old male who developed symptoms clinically consistent with EBV associated hematophagocytic lymphohistiocytosis including fulfilling most of HLH diagnostic criteria and responding promptly to HLH targeted therapy. However, histologic and cytogenetics features of this case are very concerning for EBV-positive T cell lymphoproliferative disease of childhood. This case demonstrates an ambiguous boundary of these two disease entities and emphasizes the importance of comprehensive evaluation and clinical correlation with cases suspicious of EBV driven hemophagocytic or lymphoproliferative process.

Acute Promyelocytic Leukemia: A Review and Discussion of Variant Translocations.

The majority of patients with acute promyelocytic leukemia (APL) manifest the t(15;17)(q24.1;q21.2) translocation; however, a minor but significant proportion of patients with APL harbor complex, cryptic, or variant translocations, which typically involve RARA. With the exception of ZBTB16/RARA, these variants have similar morphologic and immunophenotypic features as classic APL. Study of the variant forms of APL not only gives insight into the pathogenesis of APL but also allows us to understand the mechanism of retinoid therapy. It is important to identify these cryptic and variant translocations because certain variants, including ZBTB16/RARA and STAT5B/RARA, are resistant to treatment with all-trans retinoic acid, arsenic trioxide, and anthracyclines.

Therapy-related myeloid neoplasm with bone marrow involvement, myelosarcoma, and a t(8;16)(p11.2;p13.3)-a case report.

Therapy-related leukemia is a well-documented complication of conventional therapy for cancer. Therapy-related acute myeloid leukemia (t-AML) is grouped along with therapy-related myelodysplastic syndrome (t-MDS) and therapy-related myelodysplastic syndrome/myeloproliferative neoplasms (t-MDS/MPNs) as therapy-related myeloid neoplasms (t-MNs) by the 2008 World Health Organization classification system. Therapy-related myeloid neoplasms differ clinically from their de novo counterparts in terms of response to therapy, aggressiveness of disease, and associated poor prognosis. The occurrence of extramedullary myeloid sarcomas with bone marrow involvement has been shown to be a poor prognostic indicator for patients with t-MN. The karyotype of leukemic blasts has also been reported to have a significant impact in t-MN and may predict survival and outcomes in patients. The t(8;16)(p11.2;p13.3) is a rare, balanced translocation that is frequently associated with the M4/M5 subtype of de novo acute myeloid leukemia. It has also been reported in patients with t-MN, typically in those with poor outcomes. Here we report a case of t-MN with myeloid sarcoma and bone marrow involvement in an adult patient with a karyotype of 47,XY,t(8;16)(p11.2;p13.3),+21 after rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) chemotherapy for follicular lymphoma.

Large granules in the peripheral blood smear and bone marrow aspirate of a 3-year-old male with lymphadenopathy and fever.

A 3-year-old male with oculocutaneous albinism presented with lymphadenopathy and fever. Serological testing revealed Epstein-Barr virus (EBV)-specific immunoglobulin M (IgM) and a diagnosis of infectious mononucleosis was made. A complete blood count and peripheral blood smear demonstrated mild anemia, thrombocytopenia, and neutropenia with leukocytes that contained large azurophilic and eosinophilic granules. Bone marrow examination demonstrated increased hemophagocytic histiocytes along with granulocytes that contained large eosinophilic granules. In addition to hemophagocytic lymphohistiocytosis, presumably due to acute EBV infection, the patient was diagnosed with Chediak-Higashi syndrome based on the pathognomonic granules within peripheral leukocytes and precursors. The differential diagnosis of a young patient with oculocutaneous albinism presenting with an acute viral infection includes a relatively narrow range of genetic syndromes based solely on the history of albinism. This case demonstrates the application of clinical laboratory data to presumptively diagnose Chediak-Higashi syndrome in the midst of a presentation of hemophagocytic lymphohistiocytosis secondary to acute EBV infection.