Ultrasensitive RNA in Situ Hybridization for Kappa and Lambda Light Chain mRNA in Marginal Zone Lymphoma Demonstrates Comparable Performance to Flow Cytometry

Objectives: Evaluation of light chain restriction is critical to establish clonality in B cell lymphoproliferative disorders (LPDs). Immunohistochemistry (IHC) or in situ hybridization (ISH) are commonly used to assess light chain restriction in formalin fixed, paraffin embedded (FFPE) tissues. However, except for cases with plasma cell differentiation, these techniques often fail to identify immunoglobulin light chains. An ultrasensitive technique, RNAscope, has been recently introduced which can identify light chains in cases of B cell LPDs. We analyzed the utility of this ultrasensitive method in detection of clonality and correlated with flow cytometry results when available. Methods: A tissue microarray (TMA) was constructed using 1.6 mm diameter tissue punches of 31 FFPE tissue blocks from 27 cases (figure 1) which were previously characterized as marginal zone lymphoma (MZL) by a combination of morphology, IHC, and/or flow cytometry. Cases included 8 nodal and 19 extra nodal MZL. In 2 cases, additional blocks were included to assess reproducibility. For ultrasensitive ISH RNAscope assay, 4 µ thickness tissue sections were hybridized using kappa and lambda probes, incubated overnight, counterstained with hematoxylin, cover-slipped and reviewed blindly without knowledge of prior flow cytometry results. Results: Of 18 cases with evaluable staining, 15 were clonal and 3 were polytypic. Flow cytometry was available in 14 of these 18 cases with concordance in 13/14 (93%) (figure 2). The discordant case was polytypic by flow cytometry but kappa restricted by RNAscope. The false negative flow results could be due to sampling issues. In 6 cases, staining failed and could not be evaluated. Conclusion: Ultrasensitive RNAscope is a reliable assay in the detection of clonality in FFPE tissue, particularly where fresh tissue is not available for flow cytometry. In addition, our results confirm and further expand prior observations that RNAscope is a highly sensitive and specific assay with high concordance with flow cytometry

Epstein–Barr virus-associated inflammatory pseudotumor of the spleen: report of two cases and review of the literature

We report two rare examples of Epstein–Barr virus (EBV)-associated inflammatory pseudotumor of the spleen. One patient presented with night sweats, abdominal pain, and weight loss and was found to have a splenic mass on CT scan suspected of lymphoma. The splenic mass in second patient was found incidentally at the time of work up for kidney stones. The pathologic examination of these splenectomy specimens showed similar histologic features. However, the spindle cells were composed of EBV-infected follicular dendritic cells in one case whereas the second case lacked significant follicular dendritic cell proliferation and showed only focal EBV-infected cells suggesting that these proliferations are heterogenous in nature

Nasopharyngeal carcinoma, with emphasis on its relationship to Epstein- Barr virus

Nasopharyngeal carcinoma (NPC) is an epithelial tumor with a distinct geographic distribution and a characteristic histologic appearance. It is rare in Europe and North America, but it is among the most common cancers in southern China. Genetic predisposition, environmental factors, and Epstein- Barr virus (EBV) all have been associated with the pathogenesis of this minor. There is an increasing body of evidence that among all these factors, EBV appears to be the strongest and most consistently related factor. According to the current sensitive in situ hybridization methods for the detection of EBV-encoded small RNAs (EBER), almost 100% of cases of NPC, irrespective of their histologic subtypes, have demonstrable EBERs in the nuclei of the tumor cells. In this review paper, we discuss the predisposing genetic and environmental factors and the role of EBV in the pathogenesis of this tumor with particular emphasis on the role of EBV

Splenic sea-blue (ceroid) histiocytosis due to hypertriglyceridemia: Report of a case and review of literature

Sea-blue histiocytosis is a rare condition that can be often identified in bone marrow, spleen, liver as well as other organs. It can be frequently detected in bone marrow of patients with myeloproliferative neoplasms as well as non-neoplastic conditions such as idiopathic thrombocytopenic purpura. In this study, we report pathologic findings in a case of sea-blue histiocytosis of spleen in a patient who presented with abdominal pain and elevated triglycerides. The sea-blue histiocytosis was identified as an unexpected finding in this previously healthy individual. This case illustrates the necessity of good communication between clinicians and pathologists for the identification and treatment of the underlying lipid disorders. The prior cases of sea-blue histiocytosis reported in English literature are reviewed and the differential diagnoses are discussed. Keywords: Sea-blue histiocytes, Splenomegaly, Hypertriglyceridemi

Integration of ruxolitinib into dose-intensified therapy targeted against a novel JAK2 F694L mutation in B-precursor acute lymphoblastic leukemia.

A 17-year-old girl with B-cell precursor acute lymphoblastic leukemia (BCP-ALL) with persistent minimal residual disease (MRD) who underwent standard chemotherapy was found to have a BCR-ABL1-like gene expression pattern. Genome sequencing revealed a JAK2 mutation not previously described in BCP-ALL and a potential therapeutic target. Due to concern for an on-therapy relapse, the JAK2 inhibitor ruxolitinib was incorporated into a modified chemotherapy backbone to achieve complete remission prior to stem cell transplant. Treatment was well tolerated and she had undetectable MRD prior to a matched allogeneic stem cell transplant and remained in remission at day +100

LIM domain only 2 protein expression, LMO2 germline genetic variation, and overall survival in diffuse large B-cell lymphoma in the pre-rituximab era

Both LMO2 (LIM domain only 2) mRNA and protein expression in diffuse large B-cell lymphoma (DLBCL) have been associated with superior survival. However, a role for germline genetic variation in LMO2 has not been previously reported. Immunohistochemistry (IHC) for LMO2 was conducted on tumor tissue from diagnostic biopsies, and 20 tag single nucleotide polymorphisms (SNPs) from LMO2 were genotyped from germline DNA. LMO2 IHC positivity was associated with superior survival (hazard ratio [HR] = 0.55; 95% confidence interval [CI] 0.31-0.97). Four LMO2 SNPs (rs10836127, rs941940, rs750781, rs1885524) were associated with survival after adjusting for LMO2 IHC and clinical factors (p < 0.05), and one of these SNPs (rs941940) was also associated with IHC positivity (p = 0.02). Compared to a model with clinical factors only (c-statistic = 0.676), adding the four SNPs (c-statistic = 0.751) or LMO2 IHC (c-statistic = 0.691) increased the predictive ability of the model, while inclusion of all three factors (c-statistic = 0.754) did not meaningfully add predictive ability above a model with clinical factors and the four SNPs. In conclusion, germline genetic variation in LMO2 was associated with DLBCL prognosis and provided slightly stronger predictive ability relative to LMO2 IHC status