Ductular reaction and hepatocyte ballooning identify patients with fibrosing cholestatic hepatitits after liver transplantation.

INTRODUCTION: Diagnosis of severe hepatitis C recurrence is based on analytical and histological criteria but there is little information about their correlation. AIM: To assess the accuracy of laboratory criteria for the diagnosis of fibrosing cholestatic hepatitis (FCH). PATIENTS AND METHODS: Retrospective analysis of prospectively collected data form HCV positive patients who underwent liver transplantation (LT) between 2000 and 2014 in two European university hospitals. Patients were classified according to laboratory criteria such as FCH, cholestatic hepatitis (CH) and non-cholestatic acute hepatitis (NCAH). Histological characteristics were also evaluated. RESULTS: Seventy patients with acute HCV recurrence within the first year after LT with an available liver biopsy were included in the study. Most patients were male (70%) with a median age of 58 years (50-64) and infected with genotype 1b (71.4%). Median time from LT to diagnosis of recurrence was 2.96 months (2.1-5.3). Thirty-nine patients were classified as FCH, 21 as CH and 10 as NCAH. Marked hepatocyte ballooning and ductular reaction were associated with the presence of FCH with an OR of 4.66 (p=0.047) and 20.58 (p=0.025), respectively. Considering liver biopsy as the gold standard, the sensitivity, specificity, positive and negative predictive values of the analytical criteria were 0.8, 0.5, 0.3 and 0.9, respectively. However, correlation between histological and analytical criteria was poor (k=0.033). DISCUSSION: Analytical criteria may be used to rule out the presence of FCH, but a biopsy is mandatory to confirm the diagnosis. Ductular reaction and hepatocyte ballooning were independent predictors of FCH.

Utility of histology for the diagnosis of portal hypertensive gastroenteropathy. Concordance between the endoscopic image and gastrointestinal biopsies. Role of the CD34 marker. / Utilidad de la histología para el diagnóstico de la gastroenteropatía por hipertensión portal. Concordancia entre la imagen endoscópica y las biopsias gastrointestinales. Papel del marcador CD34.

INTRODUCTION: Upper gastroscopy in patients with cirrhosis often reveals non-specific lesions, which are usually oriented as portal hypertensive gastropathy (PHG). However, the diagnosis of PHG can be difficult, both from an endoscopic and histological point of view. The study of CD34 expression, which enhances the endothelial cells of the microvasculature, could help the differential diagnosis. The objectives of this study were to evaluate the correlation between endoscopy and histology in the diagnosis of PHG and to assess the utility of CD34 in the diagnosis of PHG. MATERIAL AND METHODS: The results of immunostaining with CD34 gastric fundus biopsies from 100 cirrhotic patients and 20 controls were compared with the endoscopic images. RESULTS: The correlation between the histology and the endoscopic diagnosis of PHG was very low (kappa=0.15). In addition, the measurement of the diameter of the gastric vessels enhanced by the use of immunohistochemical staining (CD34) did not show good correlation with the endoscopic diagnosis (p=.26) and did not provide relevant information for the histological diagnosis of PHG either. DISCUSSION: The correlation between histology and endoscopy is low for the diagnosis of PHG. The use of immunostaining for CD34 does not seem to improve the diagnostic yield of the histological study.

Update on Merkel Cell Carcinoma: Epidemiology, Etiopathogenesis, Clinical Features, Diagnosis, and Staging. / Actualización en el carcinoma de células de Merkel: Epidemiología, etiopatogenia, clínica, diagnóstico y estadificación.

Merkel cell carcinoma (MCC) is a rare, highly aggressive tumor, and local or regional disease recurrence is common, as is metastasis. MCC usually develops in sun-exposed skin in patients of advanced age. Its incidence has risen 4-fold in recent decades as the population has aged and immunohistochemical techniques have led to more diagnoses. The pathogenesis of MCC remains unclear but UV radiation, immunosuppression, and the presence of Merkel cell polyomavirus in the tumor genome seem to play key roles. This review seeks to update our understanding of the epidemiology, etiology, pathogenesis, and clinical features of MCC. We also review histologic and immunohistochemical features required for diagnosis. MCC staging is discussed, given its great importance in establishing a prognosis for these patients.

Acute Respiratory Distress: from syndrome to disease.

The acute respiratory distress syndrome (ARDS) is currently one of the most important critical entities given its high incidence, rate of mortality, long-term sequelae and non-specific pharmacological treatment. The histological hallmark of ARDS is diffuse alveolar damage (DAD). Approximately 50% of ARDS patients present DAD, the rest is made up of a heterogeneous group of histological patterns, many of which correspond to a well-recognized disease. For that reason, if these patterns could be diagnosed, patients could benefit from a treatment. Recently, the effect of DAD in clinical and analytical evolution of ARDS has been demonstrated, so the classical approach to ARDS as an entity defined solely by clinical, radiological and gasometrical variables should be reconsidered. This narrative review aims to examine the need to evolve from the concept of ARDS as a syndrome to ARDS as a specific disease. So we have raised 4 critical questions: a) What is a disease?; b) what is DAD?; c) how is DAD considered according to ARDS definition?, and d) what is the relationship between ARDS and DAD?

Histopathologic findings in children diagnosed with cow's milk protein allergy.

BACKGROUND: Cow's milk protein allergy is the most common cause of food allergy. The challenge test, either open or doubled-blind with a placebo control, is regarded as the criterion standard. Endoscopy and histologic findings are considered a method that can aid in the diagnosis of this entity. AIMS: The aim of this study was to describe the histopathologic findings in children suspected of cow's milk protein allergy that were seen at our hospital. MATERIAL AND METHODS: A descriptive, observational study was conducted on 116 children clinically suspected of presenting with cow's milk protein allergy that were seen at the Department of Gastroenterology and Nutrition of the Instituto Nacional de Pediatría. Upper endoscopy and rectosigmoidoscopy with biopsies were performed and the findings were described. RESULTS: Of the 116 patients, 64 (55.17%) were girls and 52 (44.83%) were boys. The rectum was the site with the greatest presence of eosinophils per field in both groups, followed by the duodenum. In general, more than 15 eosinophils were found in 46% of the patients. CONCLUSIONS: Between 40 and 45% of the cases had the histologic criterion of more than 15 to 20 eosinophils per field and the rectosigmoid colon was the most affected site. Therefore, panendoscopy and rectosigmoidoscopy with biopsy and eosinophil count are suggested.

[Orbital leiomyoma. Case report and review of the literature]. / Leiomioma intraorbitario. Caso clínico y revisión de la literatura.

Leiomyoma are slowly growing lesions arising from smooth muscle. Orbital location has been reported in 25 cases. Histological findings and no recurrence after total resection support their benign behaviour. We report an intraconal orbital haemangioleiomyoma in a 55-year-old female treated by total resection through fronto-orbital craniotomy, with no recurrence after 15 months of follow-up. Radiological and pathological features are discussed, emphasising the prognostic role of the surgery.

Presurgical diagnosis of diffuse gliomas in adults: Post-WHO 2021 practical perspectives from radiologists in neuro-oncology units.

The 2021 World Health Organization classification of CNS tumours was greeted with enthusiasm as well as an initial potential overwhelm. However, with time and experience, our understanding of its key aspects has notably improved. Using our collective expertise gained in neuro-oncology units in hospitals in different countries, we have compiled a practical guide for radiologists that clarifies the classification criteria for diffuse gliomas in adults. Its format is clear and concise to facilitate its incorporation into everyday clinical practice. The document includes a historical overview of the classifications and highlights the most important recent additions. It describes the main types in detail with an emphasis on their appearance on imaging. The authors also address the most debated issues in recent years. It will better prepare radiologists to conduct accurate presurgical diagnoses and collaborate effectively in clinical decision making, thus impacting decisions on treatment, prognosis, and overall patient care.

Myxoid liposarcoma: MRI features with histological correlation.

BACKGROUND AND AIMS: Myxoid liposarcoma is classified in the group of sarcomas with adipose differentiation, which is the second most common group of sarcomas. However, myxoid liposarcoma is not a homogeneous entity, because the behavior and clinical course of these tumours can vary widely. This study aimed to describe the magnetic resonance imaging (MRI) features of myxoid liposarcomas and to determine whether the MRI features are associated with the histologic grade and can differentiate between low-grade and high-grade tumours and thus help in clinical decision making. MATERIAL AND METHODS: We studied 36 patients with myxoid liposarcomas treated at our centre between 2010 and 2018. We analysed clinical variables (age, sex, and tumour site) and MRI features (size, depth, borders, fatty component, myxoid component, non-fatty/non-myxoid component, apparent diffusion coefficient (ADC), and type of enhancement after the administration of intravenous contrast material). We correlated the MRI features with the histologic grade and the percentage of round cells. RESULTS: In our series, patients with myxoid liposarcomas were mainly young adults (median age, 43 years). There were no differences between sexes; 97.2% were located in the lower limbs, 86.1% were deep, and 77.8% had well-defined borders. Of the 23 myxoid liposarcomas that contained no fat, 16 (69.6%) were high grade (p = 0.01). All the tumors with a myxoid component of less than 25% were high grade (p = 0.01); 83.3% of those with a non-fatty/non-myxoid component greater than 50% were high grade (p = 0.03) and 61.5% had more than 5% round cells (p = 0.01). Diffusion sequences were obtained in 14 of the 36 patients; ADC values were high (median, 2 × 10-3 mm2/s), although there were no significant associations between low-grade and high-grade tumours. Contrast-enhanced images were available for 30 (83.3%) patients; 83.3% of the tumours with heterogeneous enhancement were high grade (p = 0.01). CONCLUSIONS: MRI can be useful for differentiating between high- and low-grade myxoid liposarcomas and can help in clinical decision making.

Chronic minocycline administration improves spermatogenesis in rats.

INTRODUCTION: Minocycline is a tetracycline with promising protective effects on different organs which are completely distinct from its antibacterial effects. METHODS: To evaluate the effects of chronic administration of this agent on histological structure and sperm parameters of testes, forty adult male rats were randomly allocated into 2 equal groups I: control animals and II: treated animal that received 25mg/kg/day minocycline, orally. After 90 days of treatment, serum level of testosterone was assessed as well as sperm count, motility and morphology. Moreover, histological and histomorphometric evaluation of testes was performed including determination of height of the seminiferous germinal epithelium and perpendicular diameter of seminiferous tubules. Numbers of spermatogonia, primary spermatocytes, spermatids, Sertoli and Leydig cells were counted. Johnsen's scoring method was also performed. RESULTS: Sperm parameters significantly improved in minocycline-treated animals. Moreover, number of germ cells in different stages of development significantly increased in treatment group as compared to control. This finding was associated with better Johnsen's score and thicker epithelium in seminiferous tubules. However, serum testosterone levels, Leydig and Sertoli cell count as well as tubular diameter did not show significant changes (p>0.05). DISCUSSION: Chronic administration of minocycline is associated with improved spermatogenesis and sperm characteristics without affecting steroidogenesis in rats.

Sinonasal adenocarcinomas: Retrospective analysis from an oncology center.

INTRODUCTION AND OBJECTIVES: Sinonasal adenocarcinomas are rare and heterogeneous tumors and for this reason remain understudied. Our purpose is to analyze clinical presentation, outcomes and factors affecting survival of patients with sinonasal adenocarcinomas, treated at our institution. MATERIAL AND METHODS: Retrospective review of clinical records of patients with sinonasal adenocarcinoma, treated at a tertiary oncology institution (January 2010 to December 2019). RESULTS: Sixty patients diagnosed with adenocarcinoma were included, with male preponderance (54.90%) and a mean age of 57.5±14.9 years. Adenocarcinoma was the most frequent type of sinonasal cancer, contrary to previous reports from our institution. In most patients, it was detected at an advanced disease stage, significantly decreasing their survival rate when compared to patients diagnosed at initial stages (p<0.029). Intestinal type adenocarcinoma was established in 47 patients, the most frequent being the colonic subtype (24%). Tumors with good/moderate histologic differentiation presented a survival advantage over those that were poorly differentiated (p=0.043). The most common treatment modality was surgery followed by radiotherapy. Endoscopic resection was performed in 53% of the patients and an external approach was used in 40% of the patients. Estimated overall survival rates at 3 and 5-years were 64% and 53%, respectively, and cancer specific survival 72% and 65%, for the same period. Recurrence rate was 32% and occurred mainly locally. Disease Free Survival rate was 71% at 3 years and 65% at 5 years. CONCLUSIONS: Despite being the most common sinonasal malignancy in our sample, in contrast to other series, sinonasal adenocarcinomas are still rare tumors with a substantial local failure rate of around 30%. Advanced stage at diagnosis and histologic differentiation grade negatively affected prognosis of these tumors.

Low dose thymoglobulin versus basiliximab in cytomegalovirus positive kidney transplant recipients: Effectiveness of preemptive cytomegalovirus modified strategy.

BACKGROUND: We performed a retrospective trial to determine asymptomatic CMV reactivation and CMV disease in kidney allograft recipients with positive CMV serostatus. METHODS: Preemptive modified strategy under low dose thymoglobulin versus basiliximab induction was evaluated. Patients were monitored by CMV-polymerase chain reaction (PCR); if the viral load was >4000copies/µl, they received valganciclovir adjusted for their renal function. RESULTS: 132 recipients were included in the study, 84 and 48 receiving basiliximab and thymoglobulin induction respectively, and followed up for 12 months. Asymptomatic CMV reactivation was significantly higher for thymoglobulin (77.1% vs. 16.7%, p<0.001). Treatment groups had similar rates of CMV disease (3.6% vs. 2.1%, p 0.538). The significant difference in asymptomatic CMV reactivation between two treatment groups did not have any impact on 1 year graft function (71±26ml/min vs. 74±19ml/min; p=0.475) and no histological differences in protocol biopsies were observed among patients with asymptomatic CMV reactivation vs those without CMV reactivation. CONCLUSIONS: Due to the high asymptomatic CMV reactivation incidence in patients who received thymoglobulin induction, our results suggest that valganciclovir prophylaxis may be advantageous in CMV seropositive renal transplant recipients after low dose thymoglobulin induction. A preemptive strategy appeared to significantly reduce the likelihood of CMV disease in both groups. Rejection risk and negative impact in renal function associated with asymptomatic CMV reactivation was not found in our series.

[Three cases of urachal cyst in adults]. / Quistes de uraco en adultos. Presentación de 3 casos y revisión de la literatura.

The urachus is a thick fibrous cord that appears in the fifth month of pregnancy as a result of the allantois obliteration. Urachal cysts occur as a result of a defect in the obliteration of the duct, anomaly detected mainly in children and very rarely in adults. We present three cases of urachal cysts in adults, one of them detected during the study of abdominal pain and the other two, found incidentally during the study of other pathologies. In any case the possibility of urachal cysts was clinically suspected. Histologically, these lesions are lined by epithelium of urothelial type with expression of CK7, CK20, CK5/6, P63 and GATA3. The diagnosis of urachal cysts certainty lies in the histopathological study where the morphology, immunohistochemistry and a proper clinical-pathological correlation, allow to differentiate it from other more frequent abdominal cystic lesions in adults.

[Histological, immunohistochemical and molecular study of a paratesticular dedifferentiated liposarcoma with inflammatory myofibroblastic tumor-like features]. / Liposarcoma desdiferenciado paratesticular simulando un tumor miofibroblástico inflamatorio. Estudio histológico, inmunohistoquímico y molecular.

We report the histological, immunohistochemical, and molecular findings of a dedifferentiated liposarcoma with inflammatory myofibroblastic tumor-like features occurring in the paratesticular region. Histologically, the dedifferentiated component closely resembled an inflammatory myofibroblastic tumor. The neoplastic cells were positive for smooth muscle actin with focal CD56, CD99, Bcl2 and EMA expression. WT1, calretinin, myogenin, CK(AE1/AE3), desmin, H-caldesmon, CD34, ALK, CKIT, DOG1, MUC4 and STAT6 were negative. MDM2 showed diffuse and strong nuclear positivity in neoplastic cells and fluorescence in situ hybridization (FISH) revealed amplified MDM2 (high level) but no SYT rearrangement. Although a lipomatous component was evident macroscopically, well-differentiated liposarcomatous components were not evident in the section examined. Dedifferentiated liposarcoma can have prominent inflammatory myofibroblastic tumor-like features. Pathologists should be aware of this histological variant in order to avoid misdiagnosing dedifferentiated liposarcoma as inflammatory myofibroblastic tumor or other spindle cell tumors which have different behavioral patterns and treatment requirements.

Long-term exposure to cimetidine induced gonado-toxicity in male rats: Modulating role of Ocimum gratissimum.

BACKGROUND: Available evidence suggests that cimetidine is a reproductive toxicant that induces sexual and testicular dysfunction. Ocimum gratissimum (OG) is globally consumed for medicinal and nutritional purposes. To determine the modulating role of aqueous leaf extract of Ocimum gratissimum on cimetidine-induced gonado-toxicity, sexually mature male rats were randomized into four groups of six (n=6) rats each. Group A: control given 2ml distilled water. Group B received 500mg/kg body weight (bwt) of OG extract, Group C received 50mg/kg bwt cimetidine, and group D received 50mg/kg bwt of cimetidine+500mg/kg bwt OG extract once daily for 8 weeks via gastric gavage. Parameters tested include sperm parameters, testosterone (TT), luteinizing hormone (LH), follicle stimulating hormone (FSH) and prolactin, testicular alkaline phosphatase (ALP), acid phosphatase (ACP), lactate dehydrogenase (LDH), protein, cholesterol, glycogen, sexual behavioural parameters, and testicular histology. RESULTS: There were depletions in the seminiferous epithelium, decreased sperm quality, TT, LH, and FSH, testicular enzymes, protein, cholesterol, glycogen, and sexual behaviour increase in animals treated with cimetidine only compared to control. OG restored and improved sexual behaviour and libido as evident from increased frequencies of mount, intromission, ejaculation, and ejaculatory latency. Mount latencies, intromission, post-ejaculation, and prolactin were significantly decreased. The significantly decreased testicular activities of ALP, ACP, LDH and protein, cholesterol, glycogen concentrations, TT, LH and FSH were increased by OG administration. CONCLUSION: Ocimum gratissimum attenuated the deleterious effects of cimetidine on the testis, protected the seminiferous epithelium, restored, and boosted sexual competence, and promoted spermatogenesis.

Primary central nervous system Hodgkin lymphoma: A case report and review of the literature.

Central nervous system (CNS) involvement in the context of relapsed/refractory Hodgkin lymphoma (HL) is a quite rare, but well-known complication. Nevertheless, primary CNS-HL is an exceedingly rare condition, which diagnosis is based on well-defined morphological and immunohistochemical features, in addition to isolated involvement of the CNS. In spite of limited casuistry (just over twenty cases reported in the literature), available data agree that primary and isolated CNS-HL, when treated with a combination of surgery followed by some form of adjuvant therapy (radiotherapy±chemotherapy), carries a better prognosis than those cases with CNS involvement in the context of relapsed/refractory HL or those with CNS non-Hodgkin lymphoma. We herein report a case of a 55-year-old female patient who was diagnosed with primary CNS-HL. The patient was treated with complete surgical resection followed by intrathecal chemotherapy and whole brain radiotherapy (WBRT), showing fourteen months of disease-free survival at the time of this case report. A review of the available literature is also presented.

Ber-EP4 staining in effusion cytology: A potential source of false positives.

The distinction between reactive mesothelium and carcinoma in serous effusions can be very difficult. Immunocytochemistry (ICC) is the most widely used tool to improve the diagnostic accuracy of body fluid cytology, with several ICC markers being proposed. Ber-EP4 antibody has shown high sensitivity and specificity rates for diagnosing metastatic carcinoma. In our department, we have detected Ber-EP4 positivity in mesothelium in some cytological specimens. We reviewed all articles on Ber-EP4 staining in effusion cytology, summarized current findings and analyzed the staining pattern of all cases expressing Ber-EP4. Some cases showing Ber-EP4 positivity in mesothelium have been reported, most of which showed only weak Ber-EP4 staining or staining of less than 50% of mesothelial cells. However, some cases may show strong positivity both in cytological and histological specimens. Clinicians and pathologists should be aware of this source of misdiagnosis, and ICC results in mesothelium should be always interpreted cautiously and correlated with clinical tests, other ICC markers and patient's previous history.

Protocol for the Histologic Diagnosis of Cutaneous Melanoma: Consensus Statement of the Spanish Society of Pathology and the Spanish Academy of Dermatology and Venereology (AEDV) for the National Cutaneous Melanoma Registry. / Protocolo de diagnóstico histológico para muestras de pacientes con melanoma cutáneo. Documento de consenso de la SEAP y la AEDV para el Registro Nacional de Melanoma.

This article describes a proposed protocol for the histologic diagnosis of cutaneous melanoma developed for the National Cutaneous Melanoma Registry managed by the Spanish Academy of Dermatology and Venereology (AEDV). Following a review of the literature, 36 variables relating to primary tumors, sentinel lymph nodes, and lymph node dissection were evaluated using the modified Delphi method by a panel of 8 specialists (including 7 pathologists). Consensus was reached on the 30 variables that should be included in all pathology reports for cutaneous melanoma and submitted to the Melanoma Registry. This list can also serve as a model to guide routine reporting in pathology departments.

[Protocol for the histologic diagnosis of cutaneous melanoma: consensus statement of the Spanish Society of Pathology and the Spanish Academy of Dermatology and Venereology (AEDV) for the National Cutaneous Melanoma Registry]. / Protocolo de diagnóstico histológico para muestras de pacientes con melanoma cutáneo. Documento de consenso de la SEAP y la AEDV para el Registro Nacional de Melanoma.

This article describes a proposed protocol for the histologic diagnosis of cutaneous melanoma developed for the National Cutaneous Melanoma Registry managed by the Spanish Academy of Dermatology and Venereology (AEDV). Following a review of the literature, 36 variables relating to primary tumors, sentinel lymph nodes, and lymph node dissection were evaluated using the modified Delphi method by a panel of 8 specialists (including 7 pathologists). Consensus was reached on the 30 variables that should be included in all pathology reports for cutaneous melanoma and submitted to the Melanoma Registry. This list can also serve as a model to guide routine reporting in pathology departments.

Myxoid liposarcoma: MRI features with histological correlation. / Liposarcoma mixoide: características por resonancia magnética con correlación histológica.

BACKGROUND AND AIMS: Myxoid liposarcoma is classified in the group of sarcomas with adipose differentiation, which is the second most common group of sarcomas. However, myxoid liposarcoma is not a homogeneous entity, because the behavior and clinical course of these tumors can vary widely. This study aimed to describe the magnetic resonance imaging (MRI) features of myxoid liposarcomas and to determine whether the MRI features are associated with the histologic grade and can differentiate between low-grade and high-grade tumors and thus help in clinical decision making. MATERIAL AND METHODS: We studied 36 patients with myxoid liposarcomas treated at our center between 2010 and 2018. We analyzed clinical variables (age, sex, and tumor site) and MRI features (size, depth, borders, fatty component, myxoid component, non-fatty / non-myxoid component, apparent diffusion coefficient (ADC), and type of enhancement after the administration of intravenous contrast material). We correlated the MRI features with the histologic grade and the percentage of round cells. RESULTS: In our series, patients with myxoid liposarcomas were mainly young adults (median age, 43 years). There were no differences between sexes; 97.2% were located in the lower limbs, 86.1% were deep, and 77.8% had well-defined borders. Of the 23 myxoid liposarcomas that contained no fat, 16 (69.6%) were high grade (p=0.01). All the tumors with a myxoid component of less than 25% were high grade (p=0.01); 83.3% of those with a non-fatty / non-myxoid component greater than 50% were high grade (p=0.03) and 61.5% had more than 5% round cells (p=0.01). Diffusion sequences were obtained in 14 of the 36 patients; ADC values were high (median, 2 x 10-3 mm2/s), although there were no significant associations between low-grade and high-grade tumors. Contrast-enhanced images were available for 30 (83.3%) patients; 83.3% of the tumors with heterogeneous enhancement were high grade (p=0.01). CONCLUSIONS: MRI can be useful for differentiating between high- and low-grade myxoid liposarcomas and can help in clinical decision making.

Endoscopic and histological characteristics in patients with eosinophilic esophagitis responsive and non-responsive to proton pump inhibitors.

OBJECTIVE: To compare endoscopic and histologic features of pediatric patients with eosinophilic esophagitis (EoE) responding to proton pump inhibitor (PPI) to those not responding to PPI. METHODS: Endoscopic reports and photographs of patients with symptoms of esophageal dysfunction and ≥15 eosinophils per high-powered field (eos/hpf) in esophageal biopsies prior to PPI trial were reviewed. Patients were classified as responsive to PPI (PPIREoE) or non-responsive to PPI (PPINREoE) according to response totreatment (<15 eos/hpf) at second endoscopy after 8 weeks. RESULTS: Of the 231 patients (72.3% male), 64 (27.7%) were responsive to the proton pump inhibitors. Edema (77.3% vs. 62.5%, p=0.031) and vertical lines (69.5% vs. 51.6%, p=0.014) were more frequent in PPINREoE patients. An eosinophil count in the mid-esophagus ≥ 35 eos/HPF (25.1% vs. 12.5%) was more frequent in these patients (p=0.001). Those with eosinophil count < 15 eos/HPF in the mid-esophagus at the first endoscopy were more likely to respond to treatment with proton pump inhibitors compared to patients with 15-34 eos/HPF (p=0.004, OR: 3.26, 95% CI: 1.46-7.24) and to patients with ≥ 35 eos/HPF (p=0.006, OR: 3.20, 95% CI: 1.39-7.41). CONCLUSION: Edema and vertical lines at the endoscopy and a higher eosinophil count in the mid-esophagus were more frequent in patients who were non-responsive to proton pump inhibitors. As there were no significant differences in the other findings between the groups, it cannot be affirmed that these characteristics are sufficient to differentiate between PPINREoE and PPIREoE patients.