Type I interferon signaling pathway enhances immune-checkpoint inhibition in KRAS mutant lung tumors.

Lung cancer is the leading cause of cancer mortality worldwide. KRAS oncogenes are responsible for at least a quarter of lung adenocarcinomas, the main subtype of lung cancer. After four decades of intense research, selective inhibitors of KRAS oncoproteins are finally reaching the clinic. Yet, their effect on overall survival is limited due to the rapid appearance of drug resistance, a likely consequence of the high intratumoral heterogeneity characteristic of these tumors. In this study, we have attempted to identify those functional alterations that result from KRAS oncoprotein expression during the earliest stages of tumor development. Such functional changes are likely to be maintained during the entire process of tumor progression regardless of additional co-occurring mutations. Single-cell RNA sequencing analysis of murine alveolar type 2 cells expressing a resident Kras oncogene revealed impairment of the type I interferon pathway, a feature maintained throughout tumor progression. This alteration was also present in advanced murine and human tumors harboring additional mutations in the p53 or LKB1 tumor suppressors. Restoration of type I interferon (IFN) signaling by IFN-ß or constitutive active stimulator of interferon genes (STING) expression had a profound influence on the tumor microenvironment, switching them from immunologically "cold" to immunologically "hot" tumors. Therefore, enhancement of the type I IFN pathway predisposes KRAS mutant lung tumors to immunotherapy treatments, regardless of co-occurring mutations in p53 or LKB1.

Pretransplant CMV-Specific T-Cell Immunity But Not Dose of Antithymocyte Globulin Is Associated With Recovery of Specific Immunity After Kidney Transplantation.

BACKGROUND: This is a prospective, multicenter, observational study in cytomegalovirus (CMV)-seropositive kidney transplant recipients with pretransplant CMV-specific cell-mediated immunity (CMV-CMI) receiving antithymocyte globulin (ATG). We aimed to investigate posttransplant CMV-CMI over time and the impact of the dose-dependent ATG. METHODS: CMV-CMI was assessed at days +30, +45, +60, and +90 after transplantation with the QuantiFERON-CMV assay. A reactive result (interferon-γ [IFN-γ] ≥ 0.2 IU/mL) indicated a positive CMV-CMI. RESULTS: A total of 78 positive CMV-CMI patients were enrolled in the study, of which 59.5% had a positive CMV-CMI at day +30 and 82.7% at day +90. Multivariate logistic regression analysis showed that ATG dose was not associated with positive CMV-CMI at any point. However, pretransplant IFN-γ level (>12 IU/mL vs ≤12 IU/mL) was associated with positive CMV-CMI at day +30 (odds ratio, 12.9; 95% confidence interval, 3.1-53.3; P < .001). In addition, all the patients who did not recover CMV-CMI at day +90 had a pretransplant IFN-γ level ≤12 IU/mL. CONCLUSIONS: More than half of CMV-seropositive kidney transplant recipients receiving ATG recover (or maintain) CMV-CMI by the first month after transplantation. The pretransplant IFN-γ level, but not the ATG dose, shows a strong association with the kinetics of this recovery.

Immunogenicity and Safety of the Adjuvanted Recombinant Zoster Vaccine in Chronically Immunosuppressed Adults Following Renal Transplant: A Phase 3, Randomized Clinical Trial.

BACKGROUND: The incidence of herpes zoster is up to 9 times higher in immunosuppressed solid organ transplant recipients than in the general population. We investigated the immunogenicity and safety of an adjuvanted recombinant zoster vaccine (RZV) in renal transplant (RT) recipients ≥18 years of age receiving daily immunosuppressive therapy. METHODS: In this phase 3, randomized (1:1), observer-blind, multicenter trial, RT recipients were enrolled and received 2 doses of RZV or placebo 1-2 months (M) apart 4-18M posttransplant. Anti-glycoprotein E (gE) antibody concentrations, gE-specific CD4 T-cell frequencies, and vaccine response rates were assessed at 1M post-dose 1, and 1M and 12M post-dose 2. Solicited and unsolicited adverse events (AEs) were recorded for 7 and 30 days after each dose, respectively. Solicited general symptoms and unsolicited AEs were also collected 7 days before first vaccination. Serious AEs (including biopsy-proven allograft rejections) and potential immune-mediated diseases (pIMDs) were recorded up to 12M post-dose 2. RESULTS: Two hundred sixty-four participants (RZV: 132; placebo: 132) were enrolled between March 2014 and April 2017. gE-specific humoral and cell-mediated immune responses were higher in RZV than placebo recipients across postvaccination time points and persisted above prevaccination baseline 12M post-dose 2. Local AEs were reported more frequently by RZV than placebo recipients. Overall occurrences of renal function changes, rejections, unsolicited AEs, serious AEs, and pIMDs were similar between groups. CONCLUSIONS: RZV was immunogenic in chronically immunosuppressed RT recipients. Immunogenicity persisted through 12M postvaccination. No safety concerns arose. CLINICAL TRIALS REGISTRATION: NCT02058589.

The Failing Kidney Transplant Allograft. Transplant Nephrectomy: Current State-of-the-Art.

PURPOSE OF REVIEW: This review provides a critical literature overview of the risks and benefits of transplantectomy in patients with a failed allograft. Additionally, it offers a summary of related problems, primarily alloantibody sensitization in the event of nephrectomy and immunosuppression weaning. RECENT FINDINGS: Transplant nephrectomy has high morbidity and mortality rates. The morbidity of transplant nephrectomy (4.3 to 82%) is mostly due to hemorrhage or infection. Mortality rates range from 1.2 to 39%, and most are due to sepsis. Transvascular graft embolization has been described as a less invasive alternative technique for the management of symptomatic graft rejection, with minimal complications compared with transplantectomy. The number of patients with a failed allograft returning to dialysis is increasing. The role of allograft nephrectomy in the management of asymptomatic transplant failure is still controversial and up today continues to depend on the usual clinical practice of each institution. The less invasive transvascular embolization could have applicability in asymptomatic patients with the obvious lower morbidity and mortality rate.

Fibromyalgia syndrome and temporomandibular disorders with muscular pain. A review.

OBJECTIVES: Temporomandibular disorders (TMD) refer to a group of clinical picture affecting the masticatory muscles and temporomandibular joint that are characterized by muscular or joint pain, dysfunction (limited or altered functions) and joint noises, as well as other associated symptoms, such as tension headaches, otalgia, dizziness, tinnitus, and others. Fibromyalgia (FM) is a syndrome of unknown etiology involving generalized chronic pain accompanied, in a high percentage of cases, by other symptoms such as asthenia, anxiety, depression, sleep disturbances, and other less frequent symptoms, such as temporomandibular disorders (TMD). DATA: Data were compiled by two experienced examiners following a specific form. SOURCES: An electronic search was carried out in the Cochrane Central Register of Controlled Trials (CENTRAL), PUBMED, and SCOPUS electronic databases (up to April 2016, unrestricted by date or language). STUDY SELECTION: Comparative clinical studies with patients with both clinical pictures involving the study of pathogenic processes. CONCLUSIONS: Fibromyalgia and temporomandibular disorders with muscle pain both have profiles that affect the muscular system and therefore share many epidemiological, clinical, and physiopathological symptoms. Because of this, we are led to think that there is, if not a common etiology, at least a common pathogenesis. This article revises the physiopathological processes of both clinical pictures in an attempt to determine their similarities and likenesses. This would undoubtedly help in providing a better therapeutic approach.

Bone fractures and lumbar mineral density after renal transplantation. A long-term cross-sectional study.

BACKGROUND: The purpose of this work was to investigate the association of vertebral and peripheral fractures 10 yr after grafting with bone metabolic markers and body mass density (BMD). PATIENTS AND METHODS: One hundred thirty-eight recipients with stable graft function were included in a cross-sectional study. Graft function, biochemical mineral metabolism markers and body mass density (DEXA) were measured. Vertebral fractures were assessed by a semiquantitative analysis of lateral spine X-ray exam. RESULTS: At the time of the study, intact parathyroid hormone levels were 127.5 ± 78.4 pg/mL and serum calcidiol 20.4 ± 9.3 ng/mL. DEXA showed osteopenia in 47% and osteoporosis in 23% at lumbar spine, 51% and 14% at femoral neck, and 53% and 8% at trochanter. Eighty-five recipients presented vertebral fractures, 69 mild and 16 moderate/severe fractures. In the multivariate analysis, vertebral fractures were associated with older age (p = 0.010), length of follow-up (p = 0.022) and trochanter T-score (p = 0.038). Twenty-three patients presented peripheral fractures and 19 of them also had vertebral fractures. Patients with peripheral fractures were younger, mostly women and had lower BMD. CONCLUSIONS: Vertebral fractures were associated with lower BMD at trochanter. Most fractures were mild and were several times more frequent than in general population. Their clinical significance needs to be determined.

NLRP3 inflammasome is activated in mononuclear blood cells from patients with major depressive disorder.

INTRODUCTION: Major depressive disorder (MDD) is a very prevalent disease which pathogenic mechanism remains elusive. There are some hypotheses and pilot studies suggesting that cytokines may play an important role in MDD. In this respect, we have investigated the role of NLRP3 inflammasome complex in the maturation of caspase-1 and the processing of its substrates, IL-1ß and IL-18, in blood cells from MDD patients. METHODS: Forty MDD patients were selected for this study, twenty without treatments and twenty treated with amitriptyline, a common tricyclic antidepressant. Blood samples from twenty healthy volunteers were included in the study. The inflammasome activation was studied by Western blot and real-time PCR of NLRP3 and caspase 1 and serum levels of IL-1ß and 18. RESULTS: We observed increased gene expression of NLRP3 and caspase-1 in blood cells, and increased serum levels of IL-1ß and IL-18 in non-treated patients. IL-1ß and IL-18 correlated with Beck Depression Inventory (BDI) scores of MDD patients. Interestingly, amitriptyline treatment reduced NLRP3 and caspase-1 gene expression, and IL-1ß and IL-18 serum levels. As it is well established that oxidative stress is associated with NLRP3 inflammasome activation, we next studied mitochondrial ROS and lipid peroxidation (LPO) levels in MDD patients. Increased levels of mitochondrial ROS and LPO were observed in MDD patients, however oxidative damage was higher in MDD patients treated with amitriptyline. CONCLUSIONS: These findings provide new insight into the pathogenesis of MDD and the effects of amitriptyline treatment on NLRP3 inflammasome activation and IL-1ß and IL-18 serum levels.

Clinical symptoms in fibromyalgia are associated to overweight and lipid profile.

In order to analyze the association between body mass index (BMI), lipid profile and clinical symptoms in patients with fibromyalgia, we assessed BMI levels, lipid profile and its association with clinical symptoms in 183 patients with fibromyalgia. The patients were evaluated using tender points, FIQ and Visual Analogue Scales of pain (VAS). Serum lipid profile analysis (total cholesterol, triglyceride, HDL, LDL and VLDL), and biochemical parameters were measured in the biochemistry laboratory. The BMI distribution of the nonobese, overweight and obese patients' groups were relatively even with 37.7, 35.5 and 26.8%, respectively, with a mean BMI of 27.3 ± 4.9. The number of tender points showed significantly positive correlation with higher BMI (P < 0.05). A total of 57.9% of patients showed increased levels of total cholesterol, 63.4 % increased levels of LDL cholesterol and 19.9% high levels of triglycerides. BMI, total cholesterol and triglycerides showed high association with some clinical parameters. Overweight and lipid profile could be associated with fibromyalgia symptoms. A treatment program with weight loss strategies, and control in diet and increased physical activity is advised to patients.

Are low levels of 25-hydroxyvitamin D a risk factor for cardiovascular diseases or malignancies in renal transplantation?

BACKGROUND: Observational studies in healthy people suggest an inverse relationship between 25-hydroxy-vitamin D (25(OH)D levels) and cardiovascular diseases and malignancies. We performed an observational prospective study in renal transplant recipients to investigate the effects of vitamin D deficiency on cardiovascular and malignancy risks. METHODS: From 389 renal transplant recipients, 331 with a functioning graft at 12 months were included in the study. Mineral metabolism parameters were measured at 1, 3, 4 and 12 months. Information regarding the cardiovascular events and malignancies were collected from an electronic database. RESULTS: According to the 1-year mean of 25(OH)D levels, 75 recipients (22.7%) had a normal vitamin D status, 161 (48.6%) had insufficiency and 95 (28.7%) had deficiency in vitamin D levels. During the follow-up, 80 recipients presented at least one cardiovascular event. The total cardiovascular diseases included: 27 patients with coronary diseases, 25 with cardiac failure, 18 with arrhythmia, 11 with acute cerebrovascular events and 19 with peripheral vascular disease. Cardiovascular events were not associated with 25(OH)D levels or vitamin D status, and the 10-year cumulative incidence was 29.3% for normal vitamin D status and 31.6% for insufficiency and 51.9% for deficiency (P = 0.216). Furthermore, Cox univariate analysis showed no association between cardiovascular events and vitamin D levels or vitamin D status. In addition, 53 recipients presented at least one malignancy: 33 non-melanoma skin malignancies and 20 non-skin malignancies (5 prostate, 3 kidney and urinary tract, 2 colon, 2 lung, 2 lymphoma, 2 breast and 4 from other locations). The cumulative incidence of malignancies was 21.3% for normal vitamin D status, 22.7% for insufficiency and 16.7% for deficiency (P = 0.818). CONCLUSIONS: Our data suggested that low vitamin D levels were not associated with an increased risk of cardiovascular diseases or malignancies. However, due to the small number of patients and events, the results should not be considered as definitive. Additional studies with a higher number of patients are required to elucidate the true impact of vitamin D status on cardiovascular and malignancy risks.

[Evolution of the profile of patients attended by a hospital Geriatric Home Care Unit in the last 20 years]. / Evolución del perfil de las personas mayores atendidas por una unidad de atención domiciliaria especializada en geriatría en los últimos 20 años.

OBJECTIVE: To describe the evolution of the profile of patients attended by a Geriatric Home Care (GHC) Unit and its care activity in the last two decades. METHODS: Data on the historical activity of the AGD Unit from 2001 to 2020, grouped into 5-year periods, were recorded. Sociodemographic, clinical, functional (Functional Red Cross Scale and Barthel index) and mental (Mental Red Cross Scale) variables were collected, baseline and at inclusion to AGD. Also the waiting time until first visit, mean follow-up, origin of referral, destination at the end of the intervention, reason for consultation and cause of functional dependence were also included. A descriptive analysis was performed with the SPSSv.23 program. RESULTS: Ten thousand six hundred fifty-four patients attended in AGD (1 January 2001 to 31 December 2020). A progressive increase in age and in the number of geriatric syndromes was observed. Patients presented higher functional and cognitive decline, and the number of patients living alone and in need of private assistance increased. The duration of the intervention decreases and Primary Care remains the main source and destination at the end of the intervention, with dementia standing out as the main cause for functional dependence. CONCLUSION: The vulnerability of the populations in need of specialised geriatric care is increasing: patients are older, and have more geriatric syndromes, high functional and cognitive decline, and suffer social frailty; more work is needed to address the role of these support units in the community, as well as their coordination with Primary Care teams.

Kidney transplantation in systemic lupus erythematosus: Outcomes and prognosis. / Resultados y pronóstico del trasplante renal en pacientes con lupus eritematoso sistémico.

INTRODUCTION: The outcome and prognosis of systemic lupus erythematosus (SLE) in long-term kidney transplantation (KT) is variable. The objective of this study was to analyse the survival of the graft and the patient, comparing rates with a control group (primary glomerulonephritis [PGN]). MATERIALS AND METHODS: Forty-three patients receiving a KT with diagnosis of lupus nephritis (LN) and 367 patients with PGN were compared between January 1980 and December 2014. The survival causes of loss and death of the graft and the patient were analysed. RESULTS: There were no significant differences between the variables analysed. The graft survival at five years (80% SLE vs. 70% PGN) and 10 years (63% SLE vs. 55% PGN) and the patient at 5 years (90% SLE vs. 90% PGN) and 10 years (76% LES vs. 79% PGN) were similar. Not recurrence of LN was observed in any patient. CONCLUSIONS: Patients with SLE are similar candidates to KT than that with other immunological kidney diseases. There was no recurrence of the disease in any patient.

Autohemotherapy with ozone as a possible effective treatment for Fibromyalgia.

OBJECTIVE: The objective of this study is to evaluate the effectiveness of autohemotherapy with ozone in the management of fibromyalgia (FM). DESIGN: 20 FM patients (according to the criteria of the American College of Rheumatology), were treated with 10 sessions of ozone hemotherapy (2 sessions per week) with a concentration of 30-60 mcgr/ml. The health condition of the patients was evaluated before and after treatment, through the Fibromyalgia Impact Questionnaire (FIQ). Blood samples were obtained from all patients by venous puncture for biochemical routine analysis and serotonin levels in serum and the following peripheral blood mononuclear cells (BMCs) were isolated for oxidative stress quantification: reactive oxygen species (ROS) generation, and lipid peroxidation (LP) and protein carbonyl (PC) content, as these are signs of oxidative cell damage. RESULTS: All patients treated with ozone reported an improvement in sleep and mental alertness, a marked decrease of asthenia accompanied by a decrease of FIQ as well as tender points, and a moderate increase of serotonin levels. Also, an important decrease of LP and PC was observed; ROS also decreased, although less obvious, which indicates a reduction in oxidative stress levels. CONCLUSIONS: The autohemotherapy with ozone in patients with FM showed an important decline of tender points and FIQ score, as well as a decrease of oxidative stress levels. This treatment allows patients to face life with greater vitality and less drug use, diminishing harmful side effects. Further investigation should be carried out, including groups with more patients and clinical trials, to elucidate the effect of ozone therapy in patients suffering from FM.

Gastrointestinal lesions in chronic kidney disease patients with anaemia. / Lesiones gastrointestinales en pacientes con enfermedad renal crónica y anemia.

INTRODUCTION: Despite the frequency with which anaemia is present in patients with chronic kidney disease (CKD), its relationship with gastrointestinal lesions has not been studied. METHOD: A cross-sectional, analytical, observational study involving one year of recruitment was carried out to determine the prevalence of endoscopic gastrointestinal lesions and associated risk factors in asymptomatic patients with chronic kidney disease stages 1-5 and anaemia who had a positive qualitative immunochemical faecal occult blood test. RESULTS: A total of 9,658 patients with CKD were analysed, of which 286 (2.9%) had anaemia; 198 had a positive faecal occult blood test (47% male, 71.1±11.8 years). The endoscopic study revealed 255 lesions, with at least one lesion in 68.2% of patients, with the most prevalent being: adenomatous colorectal polyps (39.6%), acute lesions of the gastric mucosa (22.6%), neoplastic lesions 15.1%), angiodysplasia (14.4%), oesophagitis (8.4%), inflammatory bowel disease (4.8%) and ischaemic colitis (3.1%). Uraemia and acetylsalicylic acid were identified as risk factors for acute gastric mucosal lesions. Angiodysplasia was associated with alcoholism, a more advanced stage of chronic kidney disease, anaemia, and lack of response to erythropoiesis-stimulating agents. Age and refractory anaemia were risk factors for adenomatous polyps and colorectal cancer. CONCLUSION: Renal patients with anaemia could benefit from an endoscopic study due to their high prevalence of gastrointestinal lesions, particularly adenomatous polyps and colorectal cancer, which are more common in those over 50 years of age with CKD stages 3-5.

Learning to make informed health choices: Protocol for a pilot study in schools in Barcelona.

Introduction: The Informed Health Choices (IHC) project has developed learning resources to teach primary school children (10 to 12-year-olds) to assess treatment claims and make informed health choices. The aim of our study is to explore both the students' and teachers' experience when using these resources in the context of Barcelona (Spain). Methods: During the 2019-2020 school year, we will conduct a pilot study with 4 th and 5 th-year primary school students (9 to 11-year-olds) from three schools in Barcelona. The intervention in the schools will include: 1) a workshop with the teachers, and 2) lessons to the students. The data collection will include: 1) assessment of the IHC resources by the teachers before the lessons, 2) non-participatory observations during the lessons, 3) semi-structured interviews with the students after a lesson, 4) assessment of the lessons by the teachers after a lesson, 5) treatment claim assessment by the students at the end of the lessons, and 6) assessment of the IHC resources by the teachers at the end of the lessons. We will use ad hoc questionnaires and guides to register the data. We will perform a quantitative and qualitative analysis of the data to explore understandability, desirability, suitability, usefulness, facilitators and barriers of the resources. The most relevant results will be discussed and some recommendations on how to use, how to adapt (if needed), and how to implement the IHC resources to this context will be agreed. The findings of the contextualization activities could inform the design of a cluster-randomised trial, to determine the effectiveness of the IHC resources in this context prior to scaling-up its use. Ethical considerations: The study protocol has obtained an approval exemption from the Ethics Committee of the Hospital de la Santa Creu i Sant Pau (Barcelona, Spain).

Amitriptyline down-regulates coenzyme Q10 biosynthesis in lung cancer cells.

Amitriptyline, a tricyclic antidepressant, has been proposed as an antitumoral drug in oxidative therapy. Its pro-apoptotic effects, mediated by high reactive oxygen species generation, have been already described. In this study we analysed the effect of amitriptyline on the biosynthesis of coenzyme Q10 (CoQ), an essential component for electron transport and a potent membrane antioxidant involved in redox signaling. We treated H460 cells, a non-small-cell lung cancer cell line, with amitriptyline and we analysed CoQ levels by HPLC and CoQ biosynthesis rate, as well as the enzymes involved in CoQ biosynthesis by real-time PCR and Western blot. Amitriptyline treatment induced a dose-dependent decrease in CoQ levels in tumor cells. CoQ decreased levels were associated with down-regulation of the expression of COQ4 gene, as well as decreased Coq4 and Coq6 protein levels. Our findings suggest that the effect of amitriptyline on CoQ biosynthesis highlights the potential of this drug for antitumoral oxidative therapy.

Outcomes of Peritoneal Dialysis Catheter Left In Place after Kidney Transplantation.

No clear consensus has been reached regarding the optimal time to remove the peritoneal dialysis catheter (PDC) after kidney transplantation (KT). This retrospective observational study, conducted in a single peritoneal dialysis (PD) unit including all PD patients who received a KT between 1995 - 2015, was undertaken to evaluate the clinical outcomes and potential complications associated with a PDC left in place after KT. Of the 132 PD patients who received a KT, 20 were excluded from the study. Of the remaining, 112 (85%) patients with functioning KT were discharged with their PDC left in place and had it removed in a mean interval of 5 ± 3 months after KT, after achieving optimal graft function. During this follow-up period, 7 patients (6%) developed exit-site infection and there were 2 cases (2%) of peritonitis; all of them were successfully treated. Delayed PDC removal after KT is associated with low complication rates, although regular examination is needed so that mild infections can be detected early and therapy promptly instituted.

Preserved Renal Function in Kidney Transplantation over a Thrombosed Aortobifemoral Bypass Graft: The Role of Retrograde Flow and Early Thrombolysis.

Aortobifemoral bypass (ABFB) thrombosis is not uncommon, and when the artery of a renal graft is implanted on a bypass the risk of graft loss is high. We report the case of a 48-year-old woman with a previous history of ABFB under antiplatelet therapy and a kidney allograft implanted on the vascular prosthesis, who presented with acute limb ischemia and severe renal impairment. Imaging techniques revealed a complete thrombosis of the proximal left arm of the ABFB. However, a faint retrograde flow over the graft was observed thanks to the recanalization of distal left bypass by collateral native arteries. This unusual situation not previously reported in a kidney transplant setting, together with an early diagnosis, allowed graft survival until an early local thrombolysis resolved the problem. Two years later, renal function remains normal.

Colesteatoma de conducto auditivo externo: estudio de una serie de casos / Cholesteatoma of the external auditory canal: case series study

INTRODUCCIÓN Y OBJETIVOS: El colesteatoma de conducto auditivo externo (CCAE) es un proceso patológico poco frecuente, caracterizado por la invasión de tejido escamoso en un área del canal auditivo, que progresa hasta la destrucción ósea. Debido a la escasez de casos publicados hemos considerado de utilidad esta revisión. MATERIAL Y MÉTODOS: Estudio prospectivo y observacional desde el año 2000, de 18 pacientes diagnosticados clínicamente de CCAE en nuestro servicio de ORL. RESULTADOS: El porcentaje de hombres y mujeres es similar, con una edad media de diagnóstico de 60 años. La localización más frecuente es póstero-inferior y en la mayor parte de casos el origen es primario. La otalgia, la otorrea y la hipoacusia fueron los síntomas principales, siendo menos habitual el prurito y excepcional la debilidad facial. En general el tratamiento es conservador, pero resultó necesario el abordaje quirúrgico en un tercio de pacientes mediante canaloplastia, siguiendo el esquema expuesto, o la mastoidectomía, en función de la extensión de las lesiones. CONCLUSIONES: Aunque desconocemos los mecanismos patogénicos responsables de la formación y desarrollo del CCAE, la inclusión de queratina entre el epitelio y el hueso, con la participación del periostio, parecen ser los desencadenantes del proceso. El diagnóstico es clínico y su extensión determina el empleo de un tratamiento local o quirúrgico, que suele ser resolutivo

INTRODUCTION: External auditory canal cholesteatoma (EACC) is a rare entity characterized by the invasion of squamous tissue in the auditory canal, that progresses to bone destruction. Due to the scarcity of published cases of EACC, we have deemed useful this review. MATERIAL AND METHODS: Prospective and observational study from the year 2000 to the present in 18 patients clinically diagnosed with EACC in our ORL service. RESULTS: The percentage of men and women is similar, with a mean age at diagnosis of 60 years. The most frequently location was postero-inferior, and in most cases, the origin is primary. Otalgia, otorrhea and subjective hearing loss were the main symptoms, being less common the pruritus and exceptional facial weakness. Overall, the treatment is conservative, but it was necessary surgical treatment on one-third of the patients, performing canaloplasty or mastoidectomy, according to the extent of injuries. CONCLUSIONS: Although we do not know the genesis and pathogenic mechanisms responsible of EACC formation and development, the inclusion of keratin between the epithelium and bone, with the participation of the periosteum, seems to be the trigger of this process. The diagnosis is clinical, and its extension determines the use of a local or surgical treatment, which is usually resolutive