Immunohistochemical localization of HCA1 receptor in placenta in presence of fetal growth restriction.

INTRODUCTION: Glucose metabolism produces lactate and hydrogen ions in an anaerobic environment. Fetuses with intrauterine growth restriction are considered to become progressively lactacidemic as well as hypoxic. Roles of lactate in the placenta in the presence of fetal growth restriction (FGR) remain to be clarified. METHODS: Immunohistochemical localization of lactate-related substances, such as a receptor for lactate (hydroxy-carboxylic acid 1 receptor (HCA1 receptor/GPR81)), monocarboxylate transporters (MCTs) for lactate, lactate dehydrogenases (LDHs), and proteins expressed in syncytiotrophoblasts or cytotrophoblasts was examined in placentas of appropriate weight for gestational age (AGA) fetus and those showing FGR. RESULTS: Immunoreactivity for the HCA1 receptor was present in the cytoplasm of some trophoblasts, predominantly localized to their basal (fetus-facing) side, and was frequently colocalized with that for E-cadherin or serine peptidase inhibitor, Kunitz type 1 (SPINT1), a marker protein of cytotrophoblasts. Immunoreactivity for MCT1 and MCT4 was present on the basal and the microvillous (maternal-facing) membranes of trophoblasts in both groups, respectively. Clear immunoreactivity for LDHA and LDHB was also observed in the cytoplasm of trophoblasts, mainly localized to their basal side. However, there were no significant differences in immunohistochemically stained areas of lactate-related substances between AGA and late-onset FGR groups. On the other hand, there were correlations between coefficients of the presence of chorioamnionitis and the values of LDHB and E-cadherin. DISCUSSION: Immunohistochemical localization of the HCA1 receptor was predominantly observed in the cytoplasm located on the basal side of trophoblasts, suggesting a role of lactate in human placental development, including syncytialization.

Transporters, Ion Channels, and Junctional Proteins in Choroid Plexus Epithelial Cells.

The choroid plexus (CP) plays significant roles in secreting cerebrospinal fluid (CSF) and forming circadian rhythms. A monolayer of epithelial cells with tight and adherens junctions of CP forms the blood-CSF barrier to control the movement of substances between the blood and ventricles, as microvessels in the stroma of CP have fenestrations in endothelial cells. CP epithelial cells are equipped with several kinds of transporters and ion channels to transport nutrient substances and secrete CSF. In addition, junctional components also contribute to CSF production as well as blood-CSF barrier formation. However, it remains unclear how junctional components as well as transporters and ion channels contribute to the pathogenesis of neurodegenerative disorders. In this manuscript, recent findings regarding the distribution and significance of transporters, ion channels, and junctional proteins in CP epithelial cells are introduced, and how changes in expression of their epithelial proteins contribute to the pathophysiology of brain disorders are reviewed.

Transcriptional, biochemical, and immunohistochemical analyses of CaMKKß/2 splice variants that co-localize with CaMKIV in spermatids.

Ca2+/calmodulin-dependent protein kinase kinase (CaMKK) phosphorylates and activates downstream protein kinases, including CaMKI, CaMKIV, PKB/Akt, and AMPK; thus, regulates various Ca2+-dependent physiological and pathophysiological pathways. Further, CaMKKß/2 in mammalian species comprises multiple alternatively spliced variants; however, their functional differences or redundancy remain unclear. In this study, we aimed to characterize mouse CaMKKß/2 splice variants (CaMKKß-3 and ß-3x). RT-PCR analyses revealed that mouse CaMKKß-1, consisting of 17 exons, was predominantly expressed in the brain; whereas, mouse CaMKKß-3 and ß-3x, lacking exon 16 and exons 14/16, respectively, were primarily expressed in peripheral tissues. At the protein level, the CaMKKß-3 or ß-3x variants showed high expression levels in mouse cerebrum and testes. This was consistent with the localization of CaMKKß-3/-3x in spermatids in seminiferous tubules, but not the localization of CaMKKß-1. We also observed the co-localization of CaMKKß-3/-3x with a target kinase, CaMKIV, in elongating spermatids. Biochemical characterization further revealed that CaMKKß-3 exhibited Ca2+/CaM-induced kinase activity similar to CaMKKß-1. Conversely, we noted that CaMKKß-3x impaired Ca2+/CaM-binding ability, but exhibited significantly weak autonomous activity (approximately 500-fold lower than CaMKKß-1 or ß-3) due to the absence of C-terminal of the catalytic domain and a putative residue (Ile478) responsible for the kinase autoinhibition. Nevertheless, CaMKKß-3x showed the ability to phosphorylate downstream kinases, including CaMKIα, CaMKIV, and AMPKα in transfected cells comparable to CaMKKß-1 and ß-3. Collectively, CaMKKß-3/-3x were identified as functionally active and could be bona fide CaMKIV-kinases in testes involved in the activation of the CaMKIV cascade in spermatids, resulting in the regulation of spermiogenesis.

E-Cadherin Is Expressed in Epithelial Cells of the Choroid Plexus in Human and Mouse Brains.

Evidence showing the functional significance of the choroid plexus is accumulating. Epithelial cells with tight and adherens junctions of the choroid plexus play important roles in cerebrospinal fluid production and circadian rhythm formation. Although specific types of cadherin expressed in adherens junctions of choroid plexus epithelium (CPE) have been examined, they remained uncertain. Recent mass spectrometry and immunolocalization analysis revealed that non-epithelial cadherins, P- and N-cadherins, are expressed in the lateral membrane of CPE, whereas E-cadherin expression has not been confirmed in CPE of humans or mice. In this study, we examined E-cadherin expression in CPE of mice and humans by RT-PCR, immunohistochemical-, and Western blotting analyses. We confirmed, by using RT-PCR analysis, the mRNA expression of E-cadherin in the choroid plexus of mice. The immunohistochemical expression of E-cadherin was noted in the lateral membrane of CPE of mice and humans. We further confirmed, in Western blotting, the specific immunoreactivity for E-cadherin. Immunohistochemically, the expression of E- and N-cadherins or vimentin was unevenly distributed in some CPE, whereas that of E- and P-cadherins or ß-catenin frequently co-existed in other CPE. These findings indicate that E-cadherin is expressed in the lateral membrane of CPE, possibly correlated with the expression of other cadherins and cytoplasmic proteins.

Distribution of Monocarboxylate Transporters in Brain and Choroid Plexus Epithelium.

The choroid plexus (CP) plays central roles in regulating the microenvironment of the central nervous system by secreting the majority of cerebrospinal fluid (CSF) and controlling its composition. A monolayer of epithelial cells of CP plays a significant role in forming the blood-CSF barrier to restrict the movement of substances between the blood and ventricles. CP epithelial cells are equipped with transporters for glucose and lactate that are used as energy sources. There are many review papers on glucose transporters in CP epithelial cells. On the other hand, distribution of monocarboxylate transporters (MCTs) in CP epithelial cells has received less attention compared with glucose transporters. Some MCTs are known to transport lactate, pyruvate, and ketone bodies, whereas others transport thyroid hormones. Since CP epithelial cells have significant carrier functions as well as the barrier function, a decline in the expression and function of these transporters leads to a poor supply of thyroid hormones as well as lactate and can contribute to the process of age-associated brain impairment and pathophysiology of neurodegenerative diseases. In this review paper, recent findings regarding the distribution and significance of MCTs in the brain, especially in CP epithelial cells, are summarized.

Metabolites and Biomarker Compounds of Neurodegenerative Diseases in Cerebrospinal Fluid.

Despite recent advances in diagnostic procedures for neurological disorders, it is still difficult to definitively diagnose some neurodegenerative diseases without neuropathological examination of autopsied brain tissue. As pathological processes in the brain are frequently reflected in the components of cerebrospinal fluid (CSF), CSF samples are sometimes useful for diagnosis. After CSF is secreted from the choroid plexus epithelial cells in the ventricles, some flows in the brain, some is mixed with intracerebral interstitial fluid, and some is excreted through two major drainage pathways, i.e., the intravascular periarterial drainage pathway and the glymphatic system. Accordingly, substances produced by metabolic and pathological processes in the brain may be detectable in CSF. Many papers have reported changes in the concentration of substances in the CSF of patients with metabolic and neurological disorders, some of which can be useful biomarkers of the disorders. In this paper, we show the significance of glucose- and neurotransmitter-related CSF metabolites, considering their transporters in the choroid plexus; summarize the reported candidates of CSF biomarkers for neurodegenerative diseases, including amyloid-ß, tau, α-synuclein, microRNAs, and mitochondrial DNA; and evaluate their potential as efficient diagnostic tools.

Repeated insulin injection without site rotation affects skin thickness - ultrasonographic and histological evaluation.

AIMS/INTRODUCTION: The influence of repeated insulin injection on subcutaneous tissue is known, but its impact on the skin is unclear. Therefore, this study aimed to elucidate the impact of repeated insulin injections on the skin. MATERIAL AND METHODS: The properties of the skin and the subcutaneous tissue were evaluated in 52 insulin-treated adult patients with diabetes with abnormal findings at the site of self-injection (36 with subcutaneous nodules, 16 with suspected subcutaneous tissue induration) by ultrasonography. In all subjects, both normal and abnormal areas were examined. In addition, skin biopsies were performed in four subjects. RESULTS: The skin thickness of the normal and abnormal skin sites was 1.95 (1.60, 2.50) and 2.80 (2.27, 3.30) mm, respectively (median (first quartile, third quartile)), (P < 0.001). The biopsy specimens revealed slightly thickened and tight bundles of collagen in the dermis. Three patients had amyloid deposits in the subcutaneous tissue, and one also showed these in the dermis. These were positively stained for insulin antibody. CONCLUSIONS: Repeated insulin injection procedures result in skin thickening. Increased collagen fibers and possibly amyloid deposition in the dermis may be involved. The results reaffirmed the importance of appropriate site rotation in insulin injection and revealed the usefulness of ultrasonographic skin examination in evaluating the self-injection procedure.

Immunohistochemical expression of osteopontin and collagens in choroid plexus of human brains.

Evidence showing the functional significance of the choroid plexus is accumulating. Although it is clinically well-known that calcification is frequently seen in the choroid plexus of aged human brains, it is unclear why calcification occurs in the aged choroid plexus and what exert effects on the calcification has. In this study, immunohistochemical localizations of collagens and other molecules related to fibrosis or calcification were investigated on the choroid plexus of autopsied human brains. Densely fibrous or calcified materials were located in the stroma just below the epithelial cells of the choroid plexus of all human brains examined. Immunoreactivity for collagen type I was identified in the stroma just below the epithelial cells, consistent with the densely fibrous or calcified area, whereas that for collagen type III was observed in almost all stroma other than the densely fibrous or calcified areas. Linear or membranous immunoreactivity for collagen type IV was intermittently localized on the epithelium-facing side of the materials, suggesting an injured basement membrane. In addition, clear immunoreactivity for osteopontin was localized on the epithelium-facing side of the fibrous or calcified materials as well as in the cytoplasm of epithelial cells. These findings indicate that collagen type I exists in contact with osteopontin in and around the densely fibrous or calcified materials in the choroid plexus. They suggest that the densely fibrous or calcified materials are deposited in the subepithelial stroma just below an injured basement membrane of epithelial cells via the collagen type I and osteopontin.

A case of pyelocalyceal diverticulum urothelial carcinoma that was difficult to distinguish from cystic renal cell carcinoma preoperatively.

INTRODUCTION: Pyelocalyceal diverticulum is a rare disease sometimes difficult to distinguish from cysts. We report a case of urothelial carcinoma originating from a pyelocalyceal diverticulum, difficult to distinguish from cystic renal cell carcinoma preoperatively. CASE PRESENTATION: A 51-year-old Japanese man complained of gross hematuria. Computed tomography revealed a solid mass in one of the many cystic lesions in the left kidney. He was diagnosed with left cystic renal cell carcinoma and underwent retroperitoneal laparoscopic nephrectomy. Pathological examination revealed high-grade invasive urothelial carcinoma arising within the renal pyelocalyceal diverticulum. The definitive diagnosis was high-grade invasive urothelial carcinoma (pT3). In retrospect, the retrograde pyelography findings indicated the cyst and urinary tract connection. Residual ureterectomy and adjuvant chemotherapy were later performed. The patient has since been recurrence-free. CONCLUSION: Whether cystic renal cell carcinoma is suspected on imaging, pyelocalyceal diverticulum should be considered a differential diagnosis, though unlikely to be encountered in daily practice.

Apalutamide-associated skin rash in patients with prostate cancer: Histological evaluation by skin biopsy.

INTRODUCTION: Apalutamide-associated skin rash is a more common adverse event in the Japanese population than in the global population. However, its mechanism remains elusive, and limited histopathological information hampers further understanding. CASE PRESENTATION: Case 1: a 71-year-old man with metastatic castration-sensitive prostate cancer developed a skin rash after 70 days of apalutamide treatment. Case 2: a 71-year-old man with non-metastatic castration-resistant prostate cancer developed a skin rash after 71 days of apalutamide treatment. In both cases, the skin rash presented as a slightly exudative erythema. The histology showed spongiosis of the epidermis and perivascular and interstitial infiltration of lymphocytes and eosinophils in the upper dermis without necrotic keratinocytes. CONCLUSION: Apalutamide-induced skin rashes can involve an eczematous reaction clinically and histologically.

Effect of TNF-α on the expression of ABCA1 in pancreatic ß-cells.

ATP-binding cassette transporter A1 (ABCA1), a 254-kD membrane protein, is a key regulator of lipid efflux from cells to apolipoproteins. ABCA1 in pancreatic ß-cells influences insulin secretion and cholesterol homeostasis. Tumor necrosis factor (TNF)-α is a pleiotropic cytokine that elicits a wide spectrum of physiological events, including cell proliferation, differentiation, and apoptosis, and is also known to decrease glucose-dependent insulin secretion in pancreatic islets. In the present study, we examined the role of TNF-α on ABCA1 expression in rat pancreatic islets and INS-1 cells. ABCA1 protein levels decreased in response to rising concentrations of TNF-α in pancreatic islets. Real-time polymerase chain reaction analysis showed a significant decrease in ABCA1 mRNA expression. In parallel with its effect on endogenous ABCA1 mRNA levels, TNF-α suppressed the activity of a reporter construct containing the ABCA1 promoter. This effect was abrogated by BIRB796, but not by SB203580 or PD98095. The constitutively active form of p38 mitogen-activated protein kinase (MAPK) γ suppressed ABCA1 promoter activity but not p38-MAPK (α, ß), while a dominant-negative mutant of p38-MAPK γ blocked the effect of TNF-α on ABCA1 promoter activity. BIRB796 inhibited the increased cholesterol ester content induced by TNF-α. However, BIRB796 had no effect on the decreased insulin content nor ABCA1 suppression caused by TNF-α in INS-1 cells. In summary, TNF-α suppressed the expression of endogenous ABCA1 in pancreatic islets and INS-1 cells. These findings raise the possibility that TNF-α may affect insulin secretion by controlling ABCA1 expression.

Flexible magnifying endoscopy with narrow band imaging for the diagnosis of uterine cervical tumors: A cooperative study among gastrointestinal endoscopists and gynecologists to explore a novel microvascular classification system.

Narrow band imaging with magnifying endoscopy (NBI-ME), which is useful for the assessment of micro-vessels, has excellent diagnostic potential for early gastrointestinal epithelial neoplasia. Conventional diagnostic tools for uterine cervical epithelial tumors are still unsatisfactory. An accurate diagnostic tool for uterine cervical epithelial tumors is required to preserve the reproductive ability of young women with uterine cervical tumors. Flexible NBI-ME was performed in patients with cervical squamous cell lesions that required further examinations based on their Pap smear results (cytology ≥ low-grade squamous intraepithelial lesion) at Kagawa University Hospital between April 2014 and April 2015. NBI-ME results concordant with the punch biopsy sites were compared with the histological results. A retrospective review of the NBI-ME images identified abnormal NBI-ME results regarding micro-vascular patterns. All images were categorized as having abnormal features. NBI-ME revealed the following vascular pattern differences of different stage tumors: Dot-like vessels without irregular arrangements and high density in cervical intraepithelial neoplasia (CIN) CIN1-CIN2; dot-like vessels with irregular arrangements and high density in CIN3-carcinoma in situ; crawling vessels in minimum invasive cancer; and willow branch vessels and new tumor vessels in invasive cancer. NBI-ME may be an effective diagnostic tool for uterine cervical epithelial tumors, which may lead to the establishment of a novel classification system.

A Grading System Combining Tumor Budding and Nuclear Diameter Predicts Prognosis in Resected Lung Squamous Cell Carcinoma.

For lung squamous cell carcinomas, there are no histologic findings that have been universally accepted as prognostic factors. Tumor budding and nuclear grade have been recognized as prognostic factors in other carcinomas. In this study, we investigated whether pathologic findings could determine clinical outcome in Japanese patients with lung squamous cell carcinomas. Tumor slides from surgically resected lung squamous cell carcinomas (1999 to 2012) were reviewed (n=216). Tumors were evaluated for histologic subtypes, differentiation, tumor budding, nuclear diameter, and mitosis. Recurrence-free survival (RFS) and overall survival (OS) were analyzed using the log-rank test and the Cox proportional hazards model. Tumor budding and large nuclei were independent prognostic factors of a worse RFS (P<0.001 and P=0.002, respectively) and a worse OS (P<0.001 and P=0.038, respectively) on multivariate analysis after adjustment for pathologic stage and lymphatic invasion. However, histologic subtypes, differentiation, and mitotic count did not correlate with prognosis. A grading system combining tumor budding and nuclear diameter was an independent prognostic factors of a worse RFS (grade 2 vs. 1, hazard ratio [HR]=2.91; P<0.001, and grade 3 vs. 1, HR=7.60, P<0.001) and a worse OS (grade 2 vs. 1, HR=2.15; P=0.014, and grade 3 vs. 1, HR=4.54, P<0.001). We found that a grading system combining tumor budding and nuclear diameter was a significant prognostic factor among Japanese patients with resected lung squamous cell carcinoma.

Nuclear grade based on transbronchial cytology is an independent prognostic factor in patients with advanced, unresectable non-small cell lung cancer.

BACKGROUND: In patients with resected non-small cell lung cancer (NSCLC), the prognostic value of nuclear grade has been demonstrated. However, among patients with advanced, unresectable NSCLC, the prognostic usefulness of cytological nuclear grade to the authors' knowledge remains unknown. In the current study, the authors used transbronchial cytology to investigate whether nuclear morphometry correlated with clinical outcomes in patients with advanced NSCLC. METHODS: The authors reviewed patients with advanced, unresectable NSCLC who were diagnosed on transbronchial cytology and were treated at the study institution from 2007 through 2015 (97 patients). Nuclear morphometry (including major diameter) was assessed by an image analysis system and small lymphocytes were used as a reference. Overall survival (OS) and progression-free survival (PFS) were estimated using the Kaplan-Meier method, and multivariate analyses were performed using the Cox proportional hazards regression model. RESULTS: In the multivariate analysis, according to the nuclear major diameter as assessed by an image analysis system, a nuclear major diameter >15 µm was an independent prognostic factor of worse OS (hazard ratio [HR], 1.05; P = .003) and PFS (HR, 1.04; P = 0.011). According to the nuclear major diameter as assessed by small lymphocytes, a major diameter of >5 small lymphocytes was an independent prognostic factor of worse OS (HR, 1.32; P<.001) and PFS (HR, 1.20; P = 0.001). A moderately significant correlation between nuclear diameter measurements by an image analysis system and small lymphocytes was observed (P<.001; correlation coefficient, 0.662). CONCLUSIONS: Nuclear grade based on nuclear diameter was found to be independently associated with prognosis in patients with advanced, unresectable NSCLC. Cancer Cytopathol 2016;124:630-40. © 2016 American Cancer Society.

Cytopathological features of villous adenoma of the urinary bladder in urine: A rare case report.

Villous adenoma of the urinary bladder is a rare tumor that histologically mimics its enteric counterpart. Patients with an isolated villous adenoma have an excellent prognosis, but associated adenocarcinomas can frequently be identified in them as well. There is no literature that discusses the cytopathologic features of villous adenoma. Here we report a case which was diagnosed as villous adenoma histologically, which has been followed up with urine cytology. In urine cytology, many mucin producing cells are recognized. Few cell clusters show glandular formation or arrangement along the basement membrane. When glandular cells with columnar mucin-filled goblet cells are seen in urine cytology, the presence of a primary glandular lesion of the urinary bladder, such as villous adenoma, should be considered possible. Diagn. Cytopathol. 2016;44:632-635. © 2016 Wiley Periodicals, Inc.

Cytopathologic characteristics of the primary strumal carcinoid tumor of the ovary: a case report with emphasis on differential diagnostic considerations.

Primary strumal carcinoid tumor of the ovary (SCTO) is an extremely rare entity, though the survival rate is excellent if the disease is confined to one ovary. A case is presented here in which intraoperative squash smears in a 45-year-old woman with a left adnexal mass revealed dispersed or small clusters of neoplastic cells forming loosely cohesive gland-like structures with abundant cytoplasm. The nuclear chromatin was finely granular with a "salt and pepper" appearance and occasional tiny nucleoli. The position of the nucleus presented a vaguely plasmacytoid appearance. Small fragments of thyroidal colloid-like structures were also identified. A cytopathologic diagnosis of a SCTO was suggested. Further evaluation and immunohistochemical studies were conducted on formalin-fixed, paraffin-embedded material. Cords or nests of uniform cells with abundant cytoplasm, and eccentric nuclei with coarse chromatin and occasional colloidal tissue were identified on H&E sections. The tumor cells showed diffuse and strong cytoplasmic staining for chromogranin A, synaptophysin, CD56, and vimentin but were negative for calretinin, α-inhibin or CDX2. The proliferative index with MIB-1 was around 3%. Thyroidal colloid-like structures were immunoreactive for thyroglobulin and TTF-1 stains. The diagnosis of primary SCTO was confirmed based on cytopathologic, histopathological, and immunohistochemical results, and the location of the tumor. Awareness of the cytopathological findings of SCTO can assist in diagnosing this rare entity correctly.

Cytopathologic findings and differential diagnostic considerations of primary clear cell carcinoma of the lung.

Primary clear cell carcinoma (CLCC) of the lung is an extremely rare disease and is a subtype of large cell carcinoma, according to the World Health Organization (WHO) classification. A case is presented here in which intraoperative squash smears in a 53-year-old man revealed sheet and small clusters or tumor cells with prominent nucleoli and fine granular chromatin. Abundant translucent cytoplasm with occasional cytoplasmic vacuoles and intracytoplasmic eosinophilic inclusions was also identified. A cytopathologic diagnosis of a CLCC was suggested. Further evaluation and immunohistochemical studies were conducted on formalin-fixed, paraffin-embedded material. Nests of slightly acidophilic clear tumor cells with a prominent cellular membrane and an alveolar growth pattern were identified on H&E sections. Immunohistochemically, the tumor cells showed diffuse and strong membranous staining for CK(AE1/AE3), CK7, and CA19-9 but were negative for Napsin A, CK20, CDX2, TTF-1, alpha-fetoprotein, chromogranin A, synaptophysin, CD10, and CD56. The diagnosis of primary CLCC of the lung was confirmed based on cytopathologic, histopathologic, immunohistochemical results, and a detailed systemic examination to exclude a possible extrapulmonary origin. We report here the cytopathological features of CLCC of the lung with an emphasis on differential diagnostic considerations.

Cytopathologic features and differential diagnostic considerations of primary lymphoepithelioma-like carcinoma of the lung.

Primary lymphoepithelioma-like carcinoma (LELC) of the lung is an extremely rare disease that occurs more commonly in Asians, and is composed of undifferentiated carcinoma with prominent lymphoid stroma. LELC is reported to be closely associated with Epstein-Barr virus (EBV) infection. A case is presented here in which bronchial brushing smears in a 70-year-old man, revealed large clusters of neoplastic cells with scant cytoplasm. The nuclei were large, hyperchromatic, of irregular contour and with prominent nucleoli. Also identified were prominent intratumoral lymphoid infiltration and brisk mitotic figures. We detected EBV-coded small RNA in situ hybridization in smears. A cytologic diagnosis of a LELC was suggested. Further evaluation and immunohistochemical studies were conducted on formalin-fixed, paraffin-embedded material. Cords or nests of large neoplastic cells with enlarged nuclei and prominent nucleoli with marked lymphoid infiltration and lymphoid stroma were identified on H&E sections. Immunohistochemically, the tumor cells showed diffuse and strong membranous staining for CK(AE1/AE3), CK5/6, CK34ßE12, Napsin A and Bcl-2 but were negative for CK7, CK14, CK20, EMA, TTF-1, chromogranin A, synaptophysin and CD56. The proliferative index with MIB-1 was around 60%, and the p53 positive cells around 20%. The diagnosis of primary LELC of the lung was confirmed based on cytopathologic, histopathologic, immunohistochemical and EBER results, and a detailed systemic examination to exclude possible extrapulmonary (nasopharyngeal) origin. We report the cytopathological features of LELC of the lung and demonstrate here for the first time the positivity of the EBER with RNA-ISH method in smears with emphasis on differential diagnostic considerations.