Resumen El mielolipoma es un tumor benigno no funcional, la mayoría de ellos son asintomáticos y descubiertos de forma incidental a través de estudios de imagen o en es tudios de autopsia. Aun cuando la mayoría de los casos se presenta en la glándula suprarrenal, también se han informado en sitios extra-adrenales. Presentamos el caso de una mujer de 65 años de edad con un mielolipoma primario mediastinal. La tomografía computarizada de tórax mostró un tumor ovoide de bordes bien definidos de 6.5 × 4.2 cm, localizado en el mediastino posterior. Se realizó biopsia transtorácica de la lesión y el estudio microscópico reveló elementos hematopoyéticos y tejido adiposo maduro. Aun cuando los estudios de imagen como la tomografía computarizada y la resonancia mag nética son efectivos en el diagnóstico del mielolipoma primario mediastinal, la evaluación histopatológica es esencial para el diagnóstico definitivo.

Abstract Myelolipoma is a benign non-functional tumor. Most of them are asymptomatic and discovered incidentally, either through imaging studies or at autopsy. While it most commonly occurs in the adrenal gland, it has also been reported at extra-adrenal sites. We present the case of a 65-year-old woman with a primary mediastinal myelolipoma. Computer tomographic scan of the thorax showed an ovoid tumor with well-defined borders of 6.5 × 4.2 cm, located in the posterior mediastinum. A transthoracic biopsy of the lesion was made, and the microscopic observation revealed hematopoietic cells and mature adipose tissue. Although computed tomo graphy and magnetic resonance imaging are effective in diagnosing mediastinal myelolipoma, histopathological examination is essential for the definitive diagnosis.

Resumen El carcinoma tipo-linfoepitelioma pulmonar es una variante rara de carcinoma de células no pequeñas de pulmón, representa aproximadamente 0.7% de todos los casos. Está usualmente asociado con la infección por el virus de Epstein-Barr y es más prevalente en el Sureste de Asia; sin embargo, es extremadamente raro en Améri ca Latina. Informamos el caso de un hombre de 65 años de edad con un carcinoma tipo-linfoepitelioma pulmo nar, que se presentó con tos, disnea y pérdida de peso. La TAC de tórax mostró nódulo mal definido localizado en el pulmón derecho. Se realizó biopsia transtorácica de la lesión, y el estudio microscópico reveló células gran des poligonales dispuestas en mantos, infiltrados por abundantes linfocitos y células plasmáticas, alrededor del intersticio. Las células neoplásicas fueron positivas para citoqueratina 5/6 y p63, y negativas para Napsina A y el factor de transcripción tiroideo 1 (TTF-1). La expre sión de PD-L1 fue positivo (aproximadamente 100%) por inmunohistoquímica; así como el núcleo de las células neoplásicas mediante hibridación in situ para el RNA codificado por el virus de Epstein-Barr (EBER-ISH). El paciente recibió seis ciclos de un esquema combinado de quimioterapia basado en platino (gencitabina/cisplatino) más durvalumab. Presentó progresión de la enfermedad y finalmente murió 9 meses después del diagnóstico.

Abstract Pulmonary lymphoepithelioma-like carcinoma is a rare type of non-small cell lung cancer, it accounts for approximately 0.7% of all cases. It is usually associated with Epstein-Barr virus infection and is more prevalent in Southeast Asia; however, it is extremely rare in Latin America. We present a 65-year-old man with a primary pulmonary lymphoepithelioma-like carcinoma, who presented with cough, dyspnoea and weight loss. Com puter tomographic scan of the thorax showed a nodule localized in the right lung. A transthoracic biopsy of the lung lesion was made and the microscopic obser vation revealed large polygonal cells that proliferated in a nest pattern with infiltration by lymphocytes and plasma cells around the interstitium. The tumour cells were positive for citokeratin 5/6 and p63, and negative for Napsin A and thyroid transcription factor 1 (TTF-1). PD-L1 expression was positive (approximately 100%) in the immunohistochemical study, and the nuclei of the tumour cells were positive for EBV-encoded small RNA in-situ hybridization (EBER-ISH). The patient underwent six cycles of platinum-based combination (gencitabine/ carboplatin) chemotherapy plus durvalumab. He pre sented progression of the disease and finally he died 9 months after diagnosis.

ABSTRACT Background: Novel prognostic factors in patients with diffuse large B-cell lymphoma (DLBCL) are required in the era of Rituximab. Objective: The objective of the study was to study the prognostic impact of exon-16 enhancer-of-zeste homolog-2 (EZH2) mutations in patients with DLBCL. Methods: In a cohort of patients with DLBCL treated between 2015 and 2017, we analyzed the presence of EZH2 mutations and their association with clinical response (CR), relapse, progression-free survival (PFS), and overall survival (OS). Results: A total of 198 patients were included; of them, 30 (15.2%) had mutations at codon 641, in exon 16 of EZH2. Response was achieved in 151 patients (76.3%), and 43 (21.7%) relapsed or progressed during follow-up. EZH2 mutations were associated with relapse/progression (risk ratio [RR] 1.18; 95% confidence interval [CI] 0.98–1.42; p = 0.031), while a trend for not achieving a complete response was observed (RR: 0.876; 95%CI 0.74–1.038; p = 0.071). Of note, Tyr641His and Tyr641Ser EZH2 mutations were associated with shorter PFS (hazard ratio 3.234; 95% CI 1.149–9.1; p = 0.026). Conclusion: The presence of EZH2 mutations was negatively associated with relapse/progression and showed a trend for lack of complete response. Further studies are needed to define better the prognostic significance of these mutations in Mexican-Mestizo DLBCL patients.

Background The outcome of patients with primary extranodal diffuse large B-cell lymphoma (PE-DLBCL) varies according to the primary site involved. Primary gastrointestinal, breast, bone, craniofacial, and testicular DLBCL are rare extranodal manifestations of DLBCL. Objective The objective of the study was to describe the clinical course of patients with PE-DLBCL disease in a referral cancer center. Results From 637 patients, 51 (8.77%) were considered as having PE-DLBCL (25 gastrointestinal, 12 craniofacial, 6 breast, 5 bone, and 3 with primary testicular DLBCL). Complete remission was higher in all PE-DLBCL sites (100% in testicular, 92.6% craniofacial, 83.3% breast, 80% bone, and 80% gastrointestinal) compared with 73.3% in nodal DLBCL. Although 2 cases with breast PE-DLBC relapsed, they achieved a complete response with chemotherapy. The overall survival at 5 years was 100%, 80%, 78%, 58%, 58%, and 62% for patients with primary breast, primary bone, gastrointestinal, primary craniofacial, primary testicular, and nodal DLBCL, respectively. Conclusions PE-DLBCLs constitute rare, primary sites of lymphoproliferative disorders in most cases, with localized disease and good prognosis. They require a combined chemoimmunotherapy with radiotherapy in most cases to improve local and systemic disease.

Abstract: Objective: Targeted next-generation sequencing (t-NGS) has revolutionized clinical diagnosis allowing multiplexed detection of genomic alterations. This study evaluated the profile of somatic mutations by t-NGS in Mexican patients with non-small cell lung cancer (NSCLC). Materials and methods: Genomic DNA was extracted from 90 lung adenocarcinomas and sequences were generated for a panel of 48 cancer genes. Epidermal Growth Factor Receptor (EGFR) mutations were detected in parallel by quantitative PCR. Results: The mutational profile of NSCLC revealed alterations in 27 genes, where TP53 (47.8%) and EGFR (36.7%) exhibited the highest mutation rates. EGFR Q787 mutations were present in 14 cases (15.6%), 10 cases had exon 19 deletions (11.1%), seven cases had L858R (7.8%). The mutational frequency for genes like EGFR, MET, HNF1A, HER2 and GUSB was different compared to caucasian population. Conclusion: t-NGS improved NSCLC treatments efficacy due to its sensitivity and specificity. A distinct pattern of somatic mutations was found in Mexican population.

Resumen: Objetivo: La secuenciación dirigida de nueva generación (SNG) permite la detección múltiple de mutaciones. Este estudio evalúa el perfil de mutaciones somáticas por SNG en pacientes mexicanos con cáncer de pulmón de células no pequeñas (CPCNP). Material y métodos: Se aisló ADN de 90 muestras de pacientes con CPCNP y se analizarón 48 genes relacionados con cáncer. Las mutaciones del receptor del factor de crecimiento epidérmico (EGFR) se detectaron por PCR cuantitativa. Resultados. Se detectaron alteraciones en 27 genes. Las mutaciones más frecuentes fueron TP53 (47.8%) y EGFR (36.7%). En el gen EGFR, 14 casos fueron mutaciones Q787 (15.6%), 10 presentaron microdeleciones en el exón 19 (11.1%), y siete en L858R (7.8%). La frecuencia de mutación en EGFR, MET, HNF1A, HER2 y GUSB fue diferente en comparación con población caucásica. Conclusión: NGS modifica el tratamiento del paciente con CPCNP por su sensibilidad y especificidad para detectar mutaciones. La población mexicana presenta un perfil mutacional particular.

Abstract: Objective: Targeted next-generation sequencing (t-NGS) has revolutionized clinical diagnosis allowing multiplexed detection of genomic alterations. This study evaluated the profile of somatic mutations by t-NGS in Mexican patients with non-small cell lung cancer (NSCLC). Materials and methods: Genomic DNA was extracted from 90 lung adenocarcinomas and sequences were generated for a panel of 48 cancer genes. Epidermal Growth Factor Receptor (EGFR) mutations were detected in parallel by quantitative PCR. Results: The mutational profile of NSCLC revealed alterations in 27 genes, where TP53 (47.8%) and EGFR (36.7%) exhibited the highest mutation rates. EGFR Q787 mutations were present in 14 cases (15.6%), 10 cases had exon 19 deletions (11.1%), seven cases had L858R (7.8%). The mutational frequency for genes like EGFR, MET, HNF1A, HER2 and GUSB was different compared to caucasian population. Conclusion: t-NGS improved NSCLC treatments efficacy due to its sensitivity and specificity. A distinct pattern of somatic mutations was found in Mexican population.

Resumen: Objetivo: La secuenciación dirigida de nueva generación (SNG) permite la detección múltiple de mutaciones. Este estudio evalúa el perfil de mutaciones somáticas por SNG en pacientes mexicanos con cáncer de pulmón de células no pequeñas (CPCNP). Material y métodos: Se aisló ADN de 90 muestras de pacientes con CPCNP y se analizarón 48 genes relacionados con cáncer. Las mutaciones del receptor del factor de crecimiento epidérmico (EGFR) se detectaron por PCR cuantitativa. Resultados. Se detectaron alteraciones en 27 genes. Las mutaciones más frecuentes fueron TP53 (47.8%) y EGFR (36.7%). En el gen EGFR, 14 casos fueron mutaciones Q787 (15.6%), 10 presentaron microdeleciones en el exón 19 (11.1%), y siete en L858R (7.8%). La frecuencia de mutación en EGFR, MET, HNF1A, HER2 y GUSB fue diferente en comparación con población caucásica. Conclusión: NGS modifica el tratamiento del paciente con CPCNP por su sensibilidad y especificidad para detectar mutaciones. La población mexicana presenta un perfil mutacional particular.

Follicular lymphoma rarely presents with a leukemic phase and this should be considered a negative prognostic factor. Also, follicular lymphoma and myelodysplastic syndrome association has not been previously reported. Herein we present a patient who debuted with marked hyperleukocytosis and was diagnosed with follicular lymphoma, receiving CHOP-R and FCR after she relapsed. Several months later, secondary myelodysplastic changes were observed in her bone marrow. She received supportive therapy and finally progressed into acute myeloid leukemia. Although secondary myelodysplasia is known to be produced by chemotherapy, this patient additionally had trisomy 11, previously described in myelodysplasia and Burkitt's lymphoma, which could be linked to progression to acute myeloid leukemia.

La fase leucémica como presentación de un linfoma folicular es rara y debe ser considerada factor de mal pronóstico. Por otra parte, la asociación entre linfoma folicular y síndrome mielodisplásico no se ha descrito. Se presenta el caso de una paciente en la que se detectó marcada leucocitosis y a la que se diagnosticó un linfoma folicular. Recibió quimioterapia con R-CHOP y FCR cuando recayó. Meses después, se realizó un aspirado medular en el cual se observaron cambios compatibles con mielodisplasia, únicamente recibió terapia de soporte y finalmente evolucionó a leucemia mieloide aguda. Aunque se conoce que la mielodisplasia puede ser secundaria al uso de quimioterapia, la paciente presentó además trisomía del cromosoma 11, descrita previamente en mielodisplasia y linfoma tipo Burkitt, la cual pudiera estar en relación con la evolución a leucemia mieloide aguda.

Blastic plasmacytoid dendritic cell neoplasm is a rare hematological malignancy derived from immature plasmacytoid dendritic cells. The tumor cells have an immature blastic appearance, and diagnosis is based on the expression of CD4, CD56 y CD123 in the absence of other lymphoid, natural killer, or myeloid antigens. The majority of affected individuals are older people with a mean age of 66 years. Male to female ratio is approximately 3:1. Common presentation includes cutaneous lesions followed by tumor dissemination. Treatment with conventional chemotherapy is ineffective and allogeneic hematopoietic stem cell transplantation is required to achieve remission. We report three male patients, aged 23, 27 and 51 years with the disease. All had multiple, infiltrated pink plaques and nodules on the skin of their face, neck and thorax, measuring 1 to 12 cm in diameter. All tumors were histologically characterized by a monotonous proliferation of medium size cells with blastic features. Tumor cells were positive for CD123, CD56, CD4 and CD7 in all cases. After a mean of follow-up of 14.6 months, one patient died of the disease, one patient is alive and the disease relapsed after 17 months of remission and one patient is alive with no evidence of the disease.

We report a 73-year-old female patient with Castleman's disease coexistent with large B cell type non-Hodgkin's lymphoma in a right axillary lymphadenopathy. An excisional biopsy was performed: microscopically, the lymph node revealed the presence of numerous plasma cells and small lymphoid cells characteristic of Castleman's disease. An analysis of another portion of the specimen revealed lymphoid cells with large abnormal nuclei gathered locally that were CDD 79+, CD 38+ and MUM-1+ as well as positive for Kaposi sarcoma-associated herpesvirus and negative for Epstein Barr virus encoded RNA-1 (EBER).

Abstract Mediastinum sarcoma is a rare tumor that represents less than 10% of mediastinal tumors and about 1-2% of all malignancies in general. It should be approached in reference centers with multidisciplinary evaluation and multimodal management options, with an infrastructure that allows surgical resection and reconstruction and strict follow-up, taking into account the high local recurrence that is close to 30%. Therefore, we present a series of cases in 20 years of experience with the participation of several departments and adjusting the definition and management with the current literature.

Resumen El sarcoma de mediastino es un raro tumor que representa menos del 10% de los tumores del mediastino y alrededor del 1-2% de todas las neoplasias malignas en general. Debe abordarse en centros de referencia, donde se evalué multidisciplinariamente y se tengan opciones de manejo multimodal, infraestructura que permita la resección y reconstrucción quirúrgica mayor y estricto seguimiento, teniendo en cuenta la alta recurrencia local, cercana al 30%. Exponemos una serie de casos presentados a lo largo de 20 años de experiencia con la participación de varios departamentos, ajustándonos a la definición y manejo con la literatura actual.

Background: Primary vascular tumors of lymph nodes are extremely rare with the exception of AlDS-related Kaposi's sarcoma. The diagnosis of epithelioid hemangio-endothelioma (EH) is difficult to make without ancillary studies, since it is devoid of morphological features indicating its vascular nature and it may be overlooked when it appears as a primary tumor of lymph nodes. Spindle and epithelioid hemangio-endothelioma (SEH) is considered to be a variant of EH, which has been reported to occur exclusively in lymph nodes and the spleen. We report a 70-year-old male with chronic lymphocytic leukemia (CLL) and left cervical lymphadenopathy. An excisional biopsy was performed, and microscopically the lymph node showed effacement of nodal architecture by a tumor composed of spindle cells disposed in intersecting fascicles, and characterized by abundant eosinophilic cytoplasm, elongated nuclei and conspicuous nucleoli. A second population of cells had an epithelioid appearance with intracyto-plasmic vacuoles containing red blood cells. lmmunohistochemically, the tumor cells were positive for CD31 and CD34. The final diagnosis was SEH of the lymph node.

The risk of developing non-Hodgkin lymphoma (NHL) is 200 times higher in HIV-positive patients than otherwise healthy persons. Plasmablastic lymphoma (PL) represents < 3% of all NHL associated with HIV infection. The aim of this study was to review the clinical-pathologic features of PL of the gastrointestinal tract in 5 patients with HIV/aids disease. We performed a retrospective study of PL of the gastrointestinal tract diagnosed at the National Institute of Cancer at Mexico City, from 2000 to 2009. Clinical and pathological information was obtained and immunohistochemical studies were performed in paraffin-embedded tissue sections. The presence of Epstein-Barr Virus (EBV) was examined by in situ polymerase chain reaction (PCR). Four male and 1 female were included with a median of age of 29 years. Three tumors involved the ano-rectal area, one tumor the ascendant colon and one tumor the stomach. All tumors were histologically characterized by a monotonous proliferation of large lymphoid cell with plasmablastic features. Tumor cells were CD 138 / MUM-1positive and CD 20 / PAX-5 negative in all cases. EVB genome was detected by in situ PCR in 4 cases. The median of follow-up was 18 months, and revealed that three patients are alive with neoplasm disease and two patients are still alive with no evidence of the neoplasm. Recognition of this entity by pathologists and clinicians is important in order to establish the correct diagnosis and the early treatment of these patients.

Los pacientes con infección por el virus de inmunodeficiencia humana (HIV) tienen 200 veces más riesgo de desarrollar un linfoma no Hodgkin (LNH) con respecto a la población general. El linfoma plasmoblástico (LP) representa menos del 3% de todos los LNH asociados con el HIV. El objetivo de este estudio es informar las características clínico-patológicas de 5 pacientes con enfermedad HIV/sida y LP del tracto gastrointestinal. Se revisaron de forma retrospectiva los casos de LP del tracto gastrointestinal diagnosticados en el Instituto Nacional de Cancerología de la Ciudad de México en el periodo comprendido entre los años 2000 al 2009. Se analizaron las características clínico-patológicas y se realizaron cortes de bloques de tejidos embebidos en parafina para reacciones de inmunohistoquímica. La presencia del virus de Epstein Barr (VEB) se examinó por reacción en cadena de la polimerasa (PCR) in situ. De los cinco pacientes, cuatro fueron hombres y una mujer, con una mediana de edad de 29 años. Tres tumores se localizaron en la región anorrectal, uno en colon ascendente y el restante en el estómago. Histológicamente, todos los tumores se caracterizaron por una proliferación difusa de células grandes de aspecto plasmoblástico. Las células neoplásicas fueron CD 138/MUM-1 positivas y CD 20 / PAX-5 negativas. En cuatro pacientes se detectó el genoma del VEB en las células neoplásicas mediante PCR in situ. La mediana de seguimiento fue 18 meses; tres pacientes estaban vivos con enfermedad y dos sobreviven sin evidencias de la neoplasia. El diagnóstico precoz de LP como una entidad clínico-patológica es importante para establecer el tratamiento correcto y mejorar el pronóstico de estos pacientes.

Plasmablastic lymphoma (PL) is an uncommon B-cell lymphoma that is strongly associated with human immunodeficiency virus (HIV) infection, and displays distinctive affinity for extranodal presentation in the oral cavity. We report the case of a PL involving the stomach in a 36 year-old man HIV+ patient, associated with Kaposi sarcoma (KS) in sections adjacent to lymphoma. He had a positive history of Castleman disease and KS in a lymphoid node biopsy.

El linfoma plasmablástico (LP) es un linfoma de células B poco común que está fuertemente asociado con la infección por el virus de inmunodeficiencia humana (VIH), y muestra una afinidad característica de presentación extra-ganglionar en la cavidad oral. Informamos el caso de un LP afectando el estómago en un paciente masculino de 36 años de edad con infección por VIH, asociado con sarcoma de Kaposi (SK) en áreas adyacentes al linfoma. Tenía el antecedente de enfermedad de Castleman y SK en una biopsia de ganglio linfático.

Histiocytic sarcoma (HS) is a rare malignant neoplasm of the lymphohematopoietic system, that occurs in lymph nodes, skin and at extranodal sites, particularly the gastrointestinal tract. Although it shows characteristics histoiogical and immunohistochemical features, it may be misdiagnosed. We report a 67 year-old female patient presenting with colicky abdominal pain and vomiting. A CT sean of the abdomen revealed a tumor in the ileum, that was surgically removed. On pathology, the neoplastic cells displayed large abundant eosinophilic cytoplasm, with bizarre-shaped nuclei, that expressed CD 45, CD 68 and ¡isozyme. The diagnosis of HS requires the use of a panel of immunohistochemical markers and may be supported by ultrastructural findings .

Myxoid liposarcoma often metastasizes to extrapulmonar sites; however, osseous metastases are rare. We report the case of a 5 2-year-old male with a single histologically proven bone metastasis of the thoracic wall from a primary myxoid liposarcoma with a round cell component of the right thigh.

El liposarcoma mixoide frecuentemente presenta metástasis a sitios extrapulmonares. Sin embargo, las metástasis óseas son relativamente raras. Informamos el caso de un hombre de 52 años con metástasis ósea única a la pared torácica de un liposarcoma mixoide, con componente de células redondas, primario de muslo.