Dysregulated Repeat Element Viral-like Immune Response in Hepatocellular Carcinoma.

Purpose: Dysregulation of viral-like repeat RNAs are a common feature across many malignancies that are linked with immunological response, but the characterization of these in hepatocellular carcinoma (HCC) is understudied. In this study, we performed RNA in situ hybridization (RNA-ISH) of different repeat RNAs, immunohistochemistry (IHC) for immune cell subpopulations, and spatial transcriptomics to understand the relationship of HCC repeat expression, immune response, and clinical outcomes. Experimental Design: RNA-ISH for LINE1, HERV-K, HERV-H, and HSATII repeats and IHC for T-cell, Treg, B-cell, macrophage, and immune checkpoint markers were performed on 43 resected HCC specimens. Spatial transcriptomics on tumor and vessel regions of interest was performed on 28 specimens from the same cohort. Results: High HERV-K and high LINE1 expression were both associated with worse overall survival. There was a positive correlation between LINE1 expression and FOXP3 T-regulatory cells (r = 0.51 p < 0.001) as well as expression of the TIM3 immune checkpoint (r = 0.34, p = 0.03). Spatial transcriptomic profiling of HERV-K high and LINE-1 high tumors identified elevated expression of multiple genes previously associated with epithelial mesenchymal transition, cellular proliferation, and worse overall prognosis in HCC including SSX1, MAGEC2, and SPINK1. Conclusion: Repeat RNAs may serve as useful prognostic biomarkers in HCC and may also serve as novel therapeutic targets. Additional study is needed to understand the mechanisms by which repeat RNAs impact HCC tumorigenesis.

Spatial transcriptomics reveals distinct tissue niches linked with steroid responsiveness in acute gastrointestinal GVHD.

Severe acute graft-versus-host disease (aGVHD) is associated with significant mortality and morbidity, especially in steroid-resistant (SR) cases. Spatial transcriptomic technology can elucidate tissue-based interactions in vivo and possibly identify predictors of treatment response. Tissue sections from 32 treatment-naïve patients with biopsy-confirmed lower gastrointestinal (GI) aGVHD were obtained. The GeoMx digital spatial profiler was used to capture transcriptome profiles of >18 000 genes from different foci of immune infiltrates, colonic epithelium, and vascular endothelium. Each tissue compartment sampled showed 2 distinct clusters that were analyzed for differential expression and spatially resolved correlation of gene signatures. Classic cell-mediated immunity signatures, normal differentiated epithelial cells, and inflamed vasculature dominated foci sampled from steroid-sensitive cases. In contrast, a neutrophil predominant noncanonical inflammation with regenerative epithelial cells and some indication of angiogenic endothelial response was overrepresented in areas from SR cases. Evaluation of potential prognostic biomarkers identified ubiquitin specific peptidase 17-like (USP17L) family of genes as being differentially expressed in immune cells from patients with worsened survival. In summary, we demonstrate distinct tissue niches with unique gene expression signatures within lower GI tissue from patients with aGVHD and provide evidence of a potential prognostic biomarker.

Bacillary Positive Tuberculous Body Fluid Smears: A Perspective on How Fast to Use Acid Fast.

Background Tuberculous effusions are common. Classically, they are described as bacteria poor and lymphocyte rich. Our experience, however, has been more varied. We compiled this rare group of bacteria-positive tuberculous fluids to document their cytologic spectrum and to look for possible predictors of bacillary positivity. Methods Fifty-one cases of bacillary positive fluids were identified and their clinicopathological details were noted. Per case, the smear background was assigned as either clear, caseous, suppurative, granular proteinaceous or frankly hemorrhagic. Fine, punched-out vacuoles in the smear background were also noted. The bacillary load in each case was classified from scanty to 3+. Eventually, the clinicopathologic variables were tabulated for frequency and studied for any association with bacillary presence. Results Only 19 of the 51 patients had a history of tuberculosis. Retropositive patients comprised a small proportion (9.8%) and did not always indicate strong (3+) bacillary positivity. The granular proteinaceous background was the most frequent (35%) pattern. Only a suppurative background was associated with strong bacillary positivity. Fine vacuoles were seen almost always with caseous and granular proteinaceous backgrounds but without statistical significance. Conclusion Tuberculous effusions can have diverse smear backgrounds, not necessarily one rich in caseous material. When tuberculosis is known or clinically suspected, non-classical findings such as abundant neutrophils or suppurative background should not dissuade one from requisitioning mycobacterial stains. In fact, acid-fast stains should probably routinely accompany Giemsa slides of clinically idiopathic effusions in endemic areas since it is still the cheapest and fastest method for a conclusive diagnosis.

Preliminary Cytomorphologic Diagnosis of Hematolymphoid Malignancies in Effusions: A Cyto-histo Correlation with Lessons on Restraint.

Background: Effusions as part of hematologic neoplasms are rare and as a primary presentation, rarer. In standalone laboratories of developing countries, resorting to techniques such as flow cytometry or immunohisto/cytochemistry may not be possible. A near definitive diagnosis on cytomorphology would, therefore, be an ideal beginning. To that end, we compiled our cases of primary hematolymphoid effusions, devising reproducible reporting categories and looked at their concordance with the final histopathology. Subjects and Methods: Fifty-four cases of primary hematolymphoid effusions over 10 years with cytology-histopathology correlation were chosen. Post morphology assessment, the cases were organized into six categories: suspicious of hematolymphoid malignancy, non-Hodgkin lymphoma-high-grade (NHL-HG), low-grade NHL (NHL-LG), Burkitt lymphoma, acute leukemias, and plasma cell dyscrasias. Discordance with histology was assigned as major and minor based mainly on therapeutic implications. Results: Concordance was seen in a good number (81.5%) of cases. The NHL-HG and NHL-LG categories contributed to 33.3% each of major discordance. Tuberculosis and epithelial malignancies comprised the bulk of the major discordance. Overdiagnosis of a high-grade lymphoma for a histologically proven low-grade follicular lymphoma was the only case with minor discordance. Conclusion: The cytologic categories used are not foolproof for hematologic neoplasms but have a fairly good concordance. A scanty abnormal population should always be viewed with suspicion and definitive labels should be avoided. While morphologic examination is fraught with danger, a good assessment directs the judicious selection of ancillary methods, and hence cannot be supplanted.

Vermiform Appendix and the Potential for Missed Pathologies.

Introduction The appendix is considered an appendage of little value and is often treated disdainfully, be it as part of evolutionary process, on a grossing table, under a microscope or while archiving specimens and slides. It is only recently, with data indicating its importance in gut immunity and as the origin of pseudomyxoma, that its space in a human body appears vindicated. Aim Our aim was to screen the histopathologic spectrum of appendix lesions observed in our hospital for rare, incidental or clinico-radiologically uncertain lesions that would help emphasize a necessary seriousness in its sampling. Method All appendectomy specimens over ten years were screened for diagnosis other than acute/chronic/resolving appendicitis and pseudomyxoma peritonei. Among the recorded rare diagnoses, one representative case each, based on interesting history or pathology, was selected for discussion. Observation Forty-three lesions were found to meet inclusion criteria comprising 12 varied etiologies. Among these, 25 had a normal-appearing appendix and 27 were not suspected on radiology or on clinical/surgical assessment. Histopathology comprised, among others, neoplastic entities such as (Diffuse large B-cell) lymphoma, metastasis, carcinoid as well as interesting non-neoplastic diagnoses such as pinworm infestation (in the elderly) and (post-menopausal) endometriosis. Conclusion Sampling and histopathologic assessment of the appendix should be compulsory, careful and representative. Each specimen must be treated as harboring a potential pathology, until microscopically proven otherwise because missed "rare" diagnoses could delay therapy or alter key management decisions as cancer staging.

SLE pericardial effusion clinically mimicking hypothyroidism and tuberculosis diagnosed on cytology with LE cells.

The occurrence of lupus erythematosus cells (LE cells) in serous body fluids is extremely uncommon but, when present, is highly specific for systemic lupus erythematosus (SLE). LE cells are commonly reported in pleural and peritoneal effusions but very rarely documented in pericardial effusion. Here, we report a case in which pericardial fluid examination clinched the diagnosis of SLE which was clinically suspected of tuberculosis/hypothyroid effusion by striking presence of LE cells on May-Grünwald Giemsa-stained and Papanicolaou stained smears. Subsequent serologic studies revealed high titers of anti-nuclear antibodies and anti-ds-DNA confirming the diagnosis of SLE. This case highlights the importance of careful examination of pericardial fluid or pleural or peritoneal fluid in the diagnosis of unsuspected cases of SLE in an era wherein "LE cell detection" is considered to be of historic interest.

Cytologic aspects of an interesting case of medullary thyroid carcinoma coexisting with Hashimoto's thyroiditis.

Among primary thyroid neoplasms, papillary thyroid carcinoma (PTC) and primary thyroid lymphoma (PTL) are known to coexist and are pathogenetically linked with Hashimoto's thyroiditis (HT). However, HT occurring in association with medullary thyroid carcinoma (MTC) is rarely documented. We report here an interesting case. A 34-year-old female with a solitary thyroid nodule underwent fine needle aspiration cytology (FNAC) that was interpreted as "MTC with admixed reactive lymphoid cells, derived possibly from a pretracheal lymph node." Total thyroidectomy specimen showed "MTC with coexisting HT." At a later stage, a follow-up FNAC from the recurrent thyroid swelling showed features consistent with HT. As an academic exercise, the initial smears on which a diagnosis of MTC was offered were reviewed to look for evidence of coexisting HT that showed scanty and patchy aggregates of reactive lymphoid cells without Hürthle cells. Our case highlights an unusual instance of MTC in concurrence with HT that can create a tricky situation for cytopathologists.