Molecular Characterization of Leptospira Species among Patients with Acute Undifferentiated Febrile Illness from the Municipality of Villeta, Colombia.

Leptospira is a bacterial genus that includes several pathogenic species related to leptospirosis. In Colombia, leptospirosis is a mandatorily reported disease, widely distributed across the country. In the Villeta municipality, leptospirosis has been identified as an important cause of febrile illness; however, to date, no studies have been performed to identify the circulating species. A genus-specific qualitative qPCR was performed on DNA extracted from febrile patients' acute-phase whole-blood samples targeting a fragment of the rrs gene. Positive qPCR samples were further amplified for the adk, icdA, LipL32, LipL41, rrs, and secY genes through conventional PCR for sequencing. All high-quality obtained sequences were further assessed through concatenated phylogenetic analysis. A total of 25% (14/56) of febrile patients' acute blood samples were positive for Leptospira spp. High-quality sequences were obtained for only five genes, and analysis through concatenated phylogeny identified that all sequences clustered within the P1/pathogenic clade; some of them formed a robustly supported clade with Leptospira santarosai, and others were closely related with other Leptospira species but exhibited considerable genetic divergence. We describe the presence of pathogenic Leptospira species among febrile patients from the Villeta municipality and identify L. santarosai and other Leptospira species as causative agents of leptospirosis in the region.

A narrative review on rare types of pancreatic cancer: should they be treated as pancreatic ductal adenocarcinomas?

Pancreatic cancer is one of the deadliest malignancies in humans and it is expected to play a bigger part in cancer burden in the years to come. Pancreatic ductal adenocarcinoma (PDAC) represents 85% of all primary pancreatic malignancies. Recently, much attention has been given to PDAC, with significant advances in the understanding of the mechanisms underpinning disease initiation and progression, along with noticeable improvements in overall survival in both localized and metastatic settings. However, given their rarity, rare histological subtypes of pancreatic cancer have been underappreciated and are frequently treated as PDAC, even though they might present non-overlapping molecular alterations and clinical behavior. While some of these rare histological subtypes are true variants of PDAC that should be treated likewise, others represent separate clinicopathological entities, warranting a different therapeutic approach. In this review, we highlight clinical, pathological, and molecular aspects of rare histological types of pancreatic cancer, along with the currently available data to guide treatment decisions.

Should rare subtypes of pancreatic cancer be treated as its most common variant (ductal adenocarcinoma)? The most common type of pancreatic cancer is ductal adenocarcinoma. While much attention has been given to the molecular aspects and treatment aspects of this disease, rare variants of pancreatic cancer have been underappreciated. Some of them present unique molecular features that suggest different treatment approaches could lead to better outcomes. In this review, we summarize information on the clinical, pathological, and molecular features of rare subtypes of pancreatic cancer, along with subtype-specific data on treatment.

Serologic Evidence of Orientia Infection among Rural Population, Cauca Department, Colombia.

We assessed serum samples collected in Cauca Department, Colombia, from 486 persons for Orientia seroreactivity. Overall, 13.8% showed reactive IgG by indirect immunofluorescence antibody assay and ELISA. Of those samples, 30% (20/67) were confirmed to be positive by Western blot, showing >1 reactive band to Orientia 56-kD or 47-kD antigens.

Chronic urticaria associated with lung adenocarcinoma - a paraneoplastic manifestation: A case report and literature review.

BACKGROUND: Urticaria is one of the most common causes of emergency room visits. It is defined as an acute inflammatory dermatosis, characterized by localized degranulation of mast cells, with consequent dermal microvascular and formation of edematous and pruritic plaques called hives. Urticaria affects the skin and tissues of the superficial mucosa. Sometimes it is accompanied by angioedema, which is characterized by deeper edema of the dermis and subcutaneous cellular tissue known as the urticarial-angioedema syndrome. About 15%-25% of the general population has suffered at least one type of urticaria at some point during their lifetime and hyperpermeability estimated at 7.6%-16% and has experienced acute urticaria that is usually self-limited and spontaneously resolves without requiring medical attention. CASE SUMMARY: We present the case of a young male patient who was referred to our department with a clinical picture of 4 mo of pruritus associated with hives of variable sizes, irregular borders, with interlesional confluence, that were non-painful, without involvement of the palms and soles of the feet but with a tendency to progression in a generalized manner. He had multiple emergency room visits and poor response to antihistamines and systemic corticosteroids. Imaging studies demonstrated nodules in the lower lingula segment, at the level of the greater fissure and in the anterior contour of the left anterior basal segment associated with parahiliar adenopathies in the absence of findings suggestive of infectious or autoimmune etiology. Segmental lobectomy was performed by thoracoscopy with resection of a lung nodule in the lingula and biopsy of the para-aortic mediastinal ganglion. The histopathological report showed the presence of poorly differentiated invasive adenocarcinoma with a solid morphological and acinar pattern with immunohistochemical description of lung tissue that expresses strong positive and diffuse reaction for thyroid transcription factor 1 (TTF-1) with negativity to P40 for a histopathological diagnosis of malignant epithelial neoplasia with expression of infiltrating adenocarcinoma. Spontaneous chronic urticaria is considered possibly secondary to lung adenocarcinoma. CONCLUSION: Chronic spontaneous urticaria is considered a paraneoplastic dermatosis with a controversial association in the literature. In the presented case, a young patient presented with chronic refractory urticaria and after an exhaustive clinical work-up was found to have a diagnosis of poorly differentiated lung adenocarcinoma with high expression of TTF-1. According to the Curth criteria, the urticaria presented by the patient is related to the oncological diagnosis. In addition, the high expression of TTF-1 documented in this case could be acting as an autoantigen that would cause chronic spontaneous urticaria. Further research evaluating a causal relationship between the TFF-1 protein and urticaria in lung cancer is needed.

Stem cells as an option for the treatment of COVID-19.

The application of stem cells is among the many strategies currently available for the treatment of multiple diseases. Stem cells are characterized as undifferentiated cells that have the ability to differentiate towards multiple lineages and self-renewal, among other attributes. Since the first umbilical cord stem cell transplant for the treatment of Fanconi anemia, the use of stem cells for the treatment of multiple diseases, including coronavirus disease 2019, has increased, showing promising results that require evaluation through research studies that include a longer follow-up time. Therefore, the main objective of this Letter is to provide an update on the use of stem cells in the treatment of severe acute respiratory syndrome coronavirus 2, as well as identify the main challenges and limitations presented by this type of therapy.

Oral involvement of sinonasal undifferentiated carcinoma: A case report and immunohistochemical study of a challenging case.

INTRODUCTION: Sinonasal undifferentiated carcinoma (SNUC) is a rare tumor highly aggressive most frequently arise in the maxillary sinus and nasal cavity. Oral involvement is extremely rare. CASE REPORT: A 62-years-old male presents a large infiltrative mass involving the hard palate and left alveolar ridge. Computed tomography showed bone destruction and invasion of paranasal sinuses and orbits. Histology revealed a malignant neoplasm consisting of small round cells with minimal cytoplasm and hyperchromatic nuclei without any connection with the oral mucosal epithelium. Immunohistochemical analysis showed epithelial origin (CK-7+, CK-20+, AE1/AE3+, EMA+) and lacked strong evidence of squamous and neuroendocrine differentiation (p63-, 34ßE12-, NSE-/+, chromogranin-, synaptophysin-). TTF-1 negative ruled out the metastatic origin. A diagnosis of SNUC subtype positive for SMARCB1 (INI1) was reached. The patient was submitted to concurrent radiotherapy and chemotherapy without signs of recurrence after 2 years. CONCLUSION: SNUC involving the oral cavity is a rare malignancy that may mimic symptoms of dental infection or sinusitis. A careful correlation of clinical, microscopic, and immunohistochemical characteristics is mandatory for early diagnosis.

Undifferentiated embryonal liver sarcoma: case report and review of the literature. / Sarcoma hepático embrionario indiferenciado: reporte de caso y revisión de la literatura.

BACKGROUND: Undifferentiated embryonal sarcoma of the liver accounts for 9-13% of malignant tumors in the pediatric age group, and is the third primary malignant neoplasm of the liver in children. However, few cases are reported in the literature. It may manifest with fever, weight loss, pain, and abdominal tumor sensation. In addition to pathology and immunohistochemistry, imaging studies are the appropriate tools for diagnosis. CASE REPORT: We present the case of a 6-year-old female patient diagnosed with undifferentiated embryonal sarcoma of the liver by surgery and subsequent biopsy results. CONCLUSIONS: When reviewing the literature, we found that this type of malignant neoplasm is not frequent in children. However, it is important to consider this type of tumor as a cause in those cases of hepatomegaly in the pediatric age.

INTRODUCCIÓN: El sarcoma hepático embrionario indiferenciado representa el 9-13% de los tumores hepáticos malignos en la edad pediátrica y es la tercera neoplasia maligna primaria de hígado en la infancia. Sin embargo, son pocos los casos reportados en la literatura. Se puede manifestar con fiebre, pérdida de peso, dolor y sensación de tumor abdominal. Los estudios de imagen, además de los estudios anatomopatológico e inmunohistoquímico, son las herramientas adecuadas para el diagnóstico. CASO CLÍNICO: Se presenta el caso de una paciente de 6 años de edad con diagnóstico de sarcoma hepático embrionario indiferenciado mediante cirugía y posterior resultado de la biopsia. CONCLUSIONES: Al revisar la literatura se encontró que este tipo de neoplasia maligna no es frecuente en la infancia. Sin embargo, es importante considerar este tipo de tumor como causa en aquellos casos de hepatomegalia en la edad pediátrica.

EWSR1-ATF1 Fusion in a Myoepithelial Carcinoma of Soft Tissue With Small Round Cell Morphology: A Potential Diagnostic Pitfall.

Myoepithelial tumors of soft tissue are rare mesenchymal neoplasms that overlap with their salivary gland and skin counterparts at both the histopathologic and molecular levels. EWSR1 gene rearrangements with various fusion partners represent a common genetic event in myoepithelial tumors of soft tissue, whether benign or malignant, and may prove useful as a diagnostic tool in difficult cases. However, the number of diagnostic entities with EWSR1 gene rearrangements has grown considerably in recent years, and there is significant morphologic and immunophenotypic overlap amongst this group, underscoring the importance of fusion testing to detect fusion partners that are characteristic of discrete diagnostic entities. Herein, we report a malignant myoepithelial tumor of soft tissue/myoepithelial carcinoma with an undifferentiated round cell morphology arising in a pediatric patient with a EWSR1-ATF1 gene fusion.

Supradesnivel del segmento ST como forma de presentación atípica de un tumor cardíaco: rol diagnóstico de la multimodalidad de imagen / ST segment elevation as an atypical presentation of a cardiac tumor: diagnostic role of a multimodal imaging approach / Elevação do segmento ST como apresentação de tumor cardíaco: papel diagnóstico da multimodalidade de imagem

Los tumores cardíacos malignos son neoplasias poco frecuentes que pueden presentarse de diversas formas, lo que dificulta su diagnóstico. La ecocardiografía y la resonancia magnética cardíaca son técnicas fundamentales para el diagnóstico, la caracterización y la evaluación de su extensión tumoral. La identificación de la línea tumoral es esencial al iniciar un tratamiento oncológico dirigido. Si bien el "estándar de oro" para este fin es el estudio anatomopatológico (obtenido por biopsia o resección quirúrgica), en los casos en que esto no es posible, la resonancia magnética cardíaca es la técnica no invasiva que proporciona un mejor abordaje diagnóstico. El tratamiento de elección es la resección quirúrgica y el pronóstico, en general, es malo. Presentamos el caso de una paciente con un tumor cardíaco de presentación clínica atípica, en la que un abordaje imagenológico multimodal aporta información clave y complementaria para el diagnóstico y la caracterización tisular.

Malignant cardiac tumors are rare neoplasms that can present in various forms, making their diagnosis difficult. Echocardiography and cardiac magnetic resonance imaging are fundamental techniques for the diagnosis, characterization, and evaluation of tumor extension. Identification of the tumor line is essential when initiating targeted cancer therapy. Although the "gold standard" for this purpose is the pathological study (obtained by biopsy or surgical resection), in cases where this is not possible, cardiac resonance is the non-invasive technique that provides a better diagnostic approach. The treatment of choice is surgical resection and the prognosis is generally poor. We present the case of a patient with an atypical clinical presentation, in which a multimodal approach provides key and complementary information for tumor diagnosis and tissue characterization.

Os tumores cardíacos malignos são neoplasias raras que podem se apresentar de várias formas, dificultando seu diagnóstico. A ecocardiografia e a ressonância magnética cardíaca são técnicas fundamentais para o diagnóstico, caracterização e avaliação da extensão tumoral. A identificação da linha do tumor é essencial ao iniciar a terapia direcionada do câncer. Embora o "padrão ouro" para esse fim seja o estudo patológico (obtido por biópsia ou ressecção cirúrgica), nos casos em que isso não seja possível, a ressonância cardíaca é a técnica não invasiva que proporciona melhor abordagem diagnóstica. O tratamento de escolha é a ressecção cirúrgica e o pronóstico geralmente é ruim. Apresentamos o caso de uma paciente com apresentação clínica atípica, em que a abordagem multimodal fornece informações essenciais e complementares para o diagnóstico do tumor e caracterização do tecido.

Enfermedad indiferenciada del tejido conectivo con progresión a esclerosis sistémica / Undifferentiated disease of the connective tissue with progression to systemic sclerosis

La enfermedad indiferenciada del tejido conectivo es una condición de etiología desconocida que comparte características clínicas, patológicas y de laboratorio de varias colagenosis, sin cumplir los criterios del Colegio Americano de Reumatología para el diagnóstico de una enfermedad reumática específica y muchos pacientes evolucionan a condiciones definidas a lo largo del tiempo tales como Lupus, Esclerosis sistémica progresiva, Enfermedad de Sjögren entre otros. Antecedentes: Linfoma Hodgkin diagnosticado desde 2012 para lo cual recibió múltiples esquemas de quimioterapia. Las muestras de ganglio y médula ósea se habían enviado al laboratorio de Inmunopatologia de la Universidad de Stanford y allí no se apreciaron hallazgos compatibles con enfermedad linfoproliferativa. Enfermedad actual: Mujer de 27 años de edad con cuadro clínico de 1 mes de evolución, caracterizado por edema blando en miembros inferiores acompañado de edema palpebral matutino; concomitantemente presenta aumento de temperatura intermitente sin patrón especifico y dolor osteomuscular generalizado con limitación para la deambulación. Se ingresa. Al examen físico, regulares condiciones clínicas. En la piel se aprecia engrosamiento cutáneo importante. Se realizó biopsia cutánea y los hallazgos fueron compatibles con Esclerosis Sistémica(AU)

Undifferentiated connective tissue disease is a condition of unknown etiology that shares clinical, pathological and laboratory characteristics of several collagenopathies that do not meet the criteria of the American College of Rheumatology for the diagnosis of a specific disease; a large number of patients evolve to conditions defined over time such as Lupus, Systemic Sclerosis, Sjogren's Disease, among others. Past history: Hodgkin lymphoma was diagnosed since 2012 for which she received multiple chemotherapy schemes. A gland biopsy was sent to the Stanford University, as well as a bone marrow sample, and lymphoma was discarded. Present history: this 27-year-old female consulted for edema in lower limbs present during one month, accompanied by eyelid edema in the mornings; also fever without a specific pattern, myalgias and arthralgias. On physical examination, the skin was thickened and limb edema was present. A skin biopsy was performed, and the findings were consistent with Systemic Sclerosis. The patient is receiving cyclophosphamide and Azathioprine and leading her normal life(AU)

A rare presentation of Sinonasal Undifferentiated Carcinoma with brain metastasis and para-aortic mass.

Sinonasal Undifferentiated carcinoma (SNUC) comprises 3% of the head and neck tumors, including metastatic neoplasms. Herein we report the case of a 60-year-old male who was brought dead to our institute with previous records of a contrast-enhanced CT scan of the brain and MRI with evidence of tumor in the maxillary sinus with intracranial extensions. The histopathological examination of the mass in the maxillary sinus proved to be SNUC with metastases to the brain, lungs, and around the aorta. These tumors are undifferentiated and are distinct from other poorly differentiated tumors in deriving their origin from the Schneiderian epithelium. The aggressive nature of the tumor renders the prognosis quite dismal. SNUCs need to be early recognized and distinguished from other poorly differentiated carcinomas with the help of immunohistochemistry.

Undifferentiated carcinoma with osteoclast-like giant cells of the pancreas diagnosed by endoscopic ultrasound guided biopsy.

Undifferentiated pancreatic carcinoma with osteoclast-like giant cells is a rare tumour that has been published under a wide variety of names, including pleomorphic carcinoma, giant cell carcinoma, sarcomatoid carcinoma and carcinosarcoma, among others. For these reasons and its low frequency, the reports of these tumours are scarce and frequently lead to confusion with other entities which present with giant cells. We present the case of a patient with obstructive jaundice and a mixed cystic and solid pancreatic mass, accompanied by multiple hepatic lesions. The histological study of the material obtained by endoscopic ultrasound guided biopsy demonstrated a proliferation of atypical epithelioid cells, accompanied by a spindle cell component with marked pleomorphism and numerous osteoclast-like giant cells. The epithelioid component showed positive immunostaining with cytokeratin cocktail and cytokeratin 7. The spindle cell component showed coexpression of cytokeratins and vimentin. The osteoclast-like giant cells were positive for CD68. Protein p53 was overexpressed in both epithelial and spindle cell neoplastic components, and was negative in the giant cells. These findings permitted the diagnosis of undifferentiated carcinoma of the pancreas with osteoclast-like giant cells. This case outlines the effectiveness of endoscopic ultrasound-guided biopsy and the importance of morphological and immunohistochemical examination in the diagnosis of different types of pancreatic tumours, especially when they are in advanced stages and are not suitable for surgical treatment.

A rare presentation of Sinonasal Undifferentiated Carcinoma with brain metastasis and para-aortic mass

Sinonasal Undifferentiated carcinoma (SNUC) comprises 3% of the head and neck tumors, including metastatic neoplasms. Herein we report the case of a 60-year-old male who was brought dead to our institute with previous records of a contrast-enhanced CT scan of the brain and MRI with evidence of tumor in the maxillary sinus with intracranial extensions. The histopathological examination of the mass in the maxillary sinus proved to be SNUC with metastases to the brain, lungs, and around the aorta. These tumors are undifferentiated and are distinct from other poorly differentiated tumors in deriving their origin from the Schneiderian epithelium. The aggressive nature of the tumor renders the prognosis quite dismal. SNUCs need to be early recognized and distinguished from other poorly differentiated carcinomas with the help of immunohistochemistry.

Prevalence of undifferentiated inflammatory arthropathy in patients with Hashimoto's thyroiditis in an endocrinology clinic.

AIM: Rheumatic manifestations are common in patients with Hashimoto's thyroiditis (HT). Since previous reports on the prevalence of arthritis in this disease may have a rheumatology referral bias, we sought to establish the prevalence of undifferentiated inflammatory arthropathy (UIA) in unselected HT patients as seen in an endocrinology clinic. METHODS: Cross-sectional study of 92 consecutive HT patients and no definite rheumatic disease from the Endocrinology Division, Hospital Universitario de Caracas diagnosed by the presence of anti-thyroid peroxidase antibodies (n = 68) or typical ultrasonographic findings (n = 24). Undifferentiated inflammatory arthropathy was defined as combination of morning stiffness and joint pain with ≥2 characteristics of inflammatory joint pain. The study was revised and approved by the Ethics Committee of our hospital and all patients signed an informed consent form. RESULTS: Twenty-three patients (25%; 95% CI 16-34) met the criteria for UIA. Joints most commonly affected were the knees, hands and ankles and the most common pattern was oligoarticular (82.6%). In the multivariate analysis, variables associated to the presence of UIA were the presence of myalgia (odds ratio [OR] = 19.41; 95% CI = 2.38-158.38) and Raynaud's phenomenon (OR = 4.32; 95% CI = 1.01-18.60). No association was found with demographics, duration of disease, comorbidities or thyroid function status. CONCLUSIONS: Almost 1 in 4 patients with HT had no definite rheumatic disease present with UIA. An early identification of concurrent arthritis in HT patients is necessary for thorough differential diagnosis and prompt treatment initiation to halt potential joint damage and disability.

Carcinoma indiferenciado con células gigantes de tipo osteoclastos en la cabeza de páncreas / Undifferentiated carcinoma with osteoclast-like giant cells (uc-ogc) of the head of pancreas

El carcinoma indiferenciado con células indiferenciadas tipo osteoclasto (UC-OGC) en cabeza de páncreas, es extremadamente raro. Las características clínicopatológicas, de imagen y la apariencia topográfica no están bien clasificadas. Este reporte de caso describe un paciente con UC-OGC de cabeza de páncreas. Nuestro paciente un adulto mayor de 75 años de edad, presentaba un tiempo de enfermedad considerable, sin sintomatología relevante hasta las etapas avanzadas del tumor, debutando con molestias gástricas someras, luego pérdida de peso. En los exámenes diagnósticos hallaron la presencia de un tumor que comprometía el estómago, duodeno y páncreas. El diagnóstico definitivo lo dio el estudio anatomopatológico. No se dispone de datos clínicos suficientes para un tratamiento que garantice una mayor tasa de supervivencia en los pacientes, sin embargo, la pancreatoduodenectomía es actualmente la alternativa que mejores resultados ofrece, por otra parte, el pronóstico después de la cirugía y la tasa de recurrencia sigue incierto

Undifferentiated carcinoma with undifferentiated osteoclast-like cells (UC-OGC) in the head of the pancreas is extremely rare. The clinicalpathological, imaging and topographic appearance characteristics are not well classified. This case report describes a patient with UC-OGC of the Pancreas Head. Our patient, an adult over 75 years of age, had a considerable illness time, without relevant symptoms until the advanced stages of the tumor, debuting with shallow gastric discomfort, then weight loss. In the diagnostic tests they found the presence of a tumor that compromised the stomach, duodenum and pancreas. The definitive diagnosis was given by the pathological study. There are not enough clinical data available for a treatment that guarantees a higher survival rate in patients, however, pancreatoduodenectomy is currently the alternative that offers the best results, on the other hand, the prognosis after surgery and the recurrence rate still uncertain.

Rapidly Progressive Malignant Fibrous Histiocytoma of Right Atrium: a Rare Case Report.

We are going to present a case of malignant fibrous histiocytoma in the right atrium, which is a very rare entity. The patient had a right atrial mass, which prolapsed through the tricuspid valve into the right ventricle, causing functional tricuspid valve stenosis. The tumor was completely resected and the patient had an uneventful postoperative period. Histopathological examination reported malignant fibrous histiocytoma. The patient presented to the emergency department five weeks after discharge with dyspnea and palpitation. Echocardiography and magnetic resonance imaging revealed recurrent right atrial tumor mass. His clinical status has worsened, with syncope and acute renal failure. On the repeated echocardiography, suspected tumor recurrence was observed in left atrium, which probably caused systemic embolization. Considering the aggressive nature of the tumor and systemic involvement, our Heart Council decided to provide palliative treatment by nonsurgical management. His status deteriorated for the next few days and the patient succumbed to a cardiac arrest on the 4th day.

Rapidly progressive malignant fibrous histiocytoma of right atrium: a rare case report

Abstract We are going to present a case of malignant fibrous histiocytoma in the right atrium, which is a very rare entity. The patient had a right atrial mass, which prolapsed through the tricuspid valve into the right ventricle, causing functional tricuspid valve stenosis. The tumor was completely resected and the patient had an uneventful postoperative period. Histopathological examination reported malignant fibrous histiocytoma. The patient presented to the emergency department five weeks after discharge with dyspnea and palpitation. Echocardiography and magnetic resonance imaging revealed recurrent right atrial tumor mass. His clinical status has worsened, with syncope and acute renal failure. On the repeated echocardiography, suspected tumor recurrence was observed in left atrium, which probably caused systemic embolization. Considering the aggressive nature of the tumor and systemic involvement, our Heart Council decided to provide palliative treatment by nonsurgical management. His status deteriorated for the next few days and the patient succumbed to a cardiac arrest on the 4th day.

Patrones de tinción de anticuerpos antinucleares identificados por Inmunofluorescencia indirecta en pacientes con enfermedad del tejido conectivo / Antinuclear antibody staining patterns identified by indirect immunofluorescence in patients with connective tissue disease

Objetivos: Determinar la frecuencia de patrones de tinción de anticuerpos antinucleares identificados por inmunofluorescencia indirecta en pacientes con enfermedad del tejido conectivo en un hospital de nivel III de Lima, Perú. Material y métodos: Estudio de tipo cuantitativo, observacional y transversal, realizado en el Servicio de Inmunología del Hospital Nacional Arzobispo Loayza entre enero 2017 y junio 2017. Se revisaron 291 historias clínicas de pacientes con enfermedad del tejido conectivo y con detección de los patrones de tinción de anticuerpos antinucleares en suero, usando la técnica de Inmunofluorescencia Indirecta. Resultados: La frecuencia de estudios de anticuerpos antinucleares fue 322 (100 %), los patrones de anticuerpos antinucleares fueron PCNA6 (1,86%), patrón homogéneo 109(33,85%), patrón centromérico 34(10,56%), patrón moteado 135(41,93%), patrón citoplasmático 25(7,76%), patrón nucleolar 9(2,80%), patrón NUMA 1- Huso Acromático 3(0,93%) y patrón lisosoma 1(0,31%). La positividad de anticuerpos antinucleares se determinó mayormente en pacientes con lupus eritematoso sistémico 85(29.21%), esclerosis sistémica progresiva limitada (CREST) 34(11,68%), síndrome de Sjögren 77(26,46%), esclerodermia 15(5,15%), enfermedades mixtas del tejido conectivo72 (24,74%) y polimiositis 8 (2,75%). Conclusiones: Se encontró elevada frecuencia del patrón homogéneo y del patrón moteado en pacientes con enfermedad del tejido conectivo. El patrón homogéneo se asoció fuertemente al lupus eritematoso sistémico y el patrón moteado se asoció al síndrome de Sjögren. Por lo tanto, el método ANA-IFI puede reducir el gasto de un trabajo inmunológico detallado con una pérdida mínima en la exactitud diagnóstica de la enfermedad. (AU)

Objectives: To determine the antinuclear antibody staining patterns identified by indirect immunofluorescence in patients with connective tissue disease in hospital level III in Lima, Peru. Methods: Cross-sectional study performed at the Servicio de Inmunología of the Hospital Nacional Arzobispo Loayza between January and June 2017. We reviewed 291 clinical charts of patients with connective tissue disease who had determination of antinuclear antibodies by indirect immunofluorescence. Results: 322 determinations were analyzed; patterns detected were PCNA 6 (1.86%); homogeneous pattern 109(33.85%), centromeric pattern 34(10.56%), speckled pattern 135(41.93%), cytoplasmic pattern 25(7.76%), nucleolar pattern 9(2.80%), NUMA 1- Huso achromatic pattern 3(0.93%) and lysosomal pattern 1(0.31%). The spectrum of diseases in which antinuclear antibodies were looked for were systemic lupus 85(29.21%), limited progressive systemic sclerosis CREST) 34(11.68%), Sjögren´s syndrome 77(26.46%), scleroderma 15(5.15%), mixed connective tissue disorders 72 (24.74%) and polymyositis 8 (2.75%). Conclusions: A high frequency of homogeneous and speckled patterns were observed, the former associated with systemic lupus and the latter with Sjögren´s syndrome. Detection of antinuclear antibodies by indirect immunofluorescence is an accurate diagnostic method. (AU)