Clear cell chondrosarcoma of the proximal tibia - case report

ABSTRACT Introduction: Clear cell chondrosarcomas are a rare type of low-grade chondrosarcoma. Unlike conventional chondrosarcomas, these tumors occur mainly in the epiphyses of long bones, especially in the proximal femur and proximal humerus. Given their lytic characteristics with a cystic appearance, they can be mistaken for bone cysts and diagnosed late. Diagnosis must be made based on histopa-thology and immunohistochemistry. Likewise, negativity for cytokeratins and anti-endomysial antibodies are tools to rule out the differential diagnosis of metastasis. The treatment of this low-grade chondral lesion is surgical, either with intralesional management or complete resection. Case presentation: This is the case of a 46-year-old woman who consulted the orthopedic oncology service of a quaternary care institution due to medial knee pain at the level of the proximal tibia for 8 months. Diagnostic imaging studies showed a cystic lesion in the lateral tibial plateau; a biopsy of the lesion was performed, and clear cell chondrosarcoma was diagnosed based on histopathology and immunohistochemistry. Surgical management included tumor-free resection margins and reconstruction of the bone defect with a structural allograft of the proximal tibia. The patient progressed satisfactorily. Conclusions: This was the case of a patient with a subtype of low-grade chondrosarcoma that is rare in incidence and location, who was diagnosed based on immunohistochemistry and treated surgically to achieve a successful limb salvage.

RESUMEN Introducción. El condrosarcoma de células claras es un subtipo de tumor poco frecuente del grupo de los condrosarcomas de bajo grado. A diferencia de los condrosarcomas convencionales, estos tumores se presentan principalmente en epífisis de huesos largos. Dadas sus características líticas de aspecto quístico, pueden confundirse con quistes óseos, por lo que su diagnóstico debe hacerse por histopatología e inmunohistoquímica mediante biopsia. Igualmente, la negatividad para citoqueratinas y anticuerpos antiendomisio es una herramienta para descartar el diagnóstico diferencial de metástasis. Su tratamiento es quirúrgico, bien sea con manejo intralesional o resección completa con márgenes libres. Presentación del caso. Mujer de 46 años quien consultó al servicio de ortopedia oncológica de una institución de IV nivel de atención por un cuadro clínico de 8 meses de evolución consistente en dolor en la cara medial de la rodilla izquierda a nivel de la tibia proximaluna. Se practicaron imágenes diagnósticas que mostraron una lesión quística en el platillo tibial lateral; se ordenó biopsia de la lesión, y mediante histopatología e inmunohistoquímica se diagnosticó condrosarcoma de células claras. Se realizó un manejo quirúrgico con resección de la lesión con márgenes libres y una reconstrucción del defecto óseo con un aloinjerto estructural de tibia proximal, con lo cual se obtuvo una evolución satisfactoria. Conclusiones. Se presenta el caso de una paciente con un subtipo de condrosarcoma de bajo grado infrecuente en su presentación y localización, quien fue diagnosticada mediante inmunohistoquímica y tratada quirúrgicamente para lograr un salvamento exitoso de su extremidad.

Solitary Fibrous Tumor in the Perianal Region: Report of Two Cases With an Atypical Location.

A solitary fibrous tumor (SFT) is a mesenchymal neoplasm of spindle cells, initially described in the pleura. The World Health Organization (WHO) classifies the solitary fibrous tumor as a neoplasm with intermediate biological potential. Diagnostic images are essential for the diagnostic and therapeutic approach in this entity. The standard of treatment for this type of lesion is surgical resection with oncological margins larger than 1 cm. The solitary fibrous tumors located in the perianal, perineal, and pelvic regions are infrequent and represent a challenge in the clinical approach, mainly because the manifestations are nonspecific. Given the low incidence of this type of neoplasm, we present two cases of SFT in the perianal region managed in a high-complexity hospital.

Inestabilidad microsatelital y cáncer gástrico / Microsatellite instability and gastric cancer

La inestabilidad microsatelital es causada por una alteración de los sistemas de reparación de apareamiento incorrecto, que puede afectar los microsatélites dentro de todo el genoma humano, produciendo errores en su replicación. Los estudios publicados, principalmente en la literatura inglesa, han encontrado que algunos tumores, como los gástricos, pueden expresar inestabilidad microsatelital. En la siguiente revisión de tema, se presenta una descripción de los sistemas de reparación de apareamientos incorrectos y su relación con la presencia de inestabilidad microsatelital en los tumores gástricos, así como su posible utilidad clínica, como factor asociado en la respuesta al tratamiento con inmunoterapia en los pacientes con dicha patología

Microsatellite instability is caused by an alteration of the mismatch repair systems, which can affect microsatellites within the entire human genome, causing errors in their replication. Published studies, mainly in the English literature, have found that some tumors, such as gastric ones, can express microsatellite instability. In this review, a description of the mismatch repair systems and their relationship with the presence of microsatellite instability in gastric tumors is presented, as well as its possible clinical utility, as an associated factor in the response to immunotherapy treatment, in patients with gastric cancer

Fibroma condromixoide en el iliaco. Reporte de caso / Chondromyxoid fibroma in the iliac. Case report

Se trata de un paciente masculino de 31 años con diagnóstico de fibroma condromixoide del ilíaco derecho manejado en el Hospital Universitario San Ignacio en febrero del 2018. El paciente fue llevado inicialmente a biopsia abierta para confirmación histológica, posteriormente fue llevado a embolización preoperatoria, manejo intralesional con curetaje, fresado extendido, manejo adyuvante local y aplicación de cemento óseo. Se realiza seguimiento postoperatorio por 18 meses sin evidencia clínica ni radiográfica de recidiva tumoral. El objetivo de este trabajo es hacer una revisión de la literatura sobre el fibroma condromixoide con énfasis en su localización pélvica y su tratamiento.

We report a case of a 31-year-old male patient with diagnosis of chondromyxoid fibroma (CMF) of the iliac bone diagnosed at Hospital Universitario San Ignacio in february 2018; an open biopsy allowed recognizement and description of cytologic features, forward diagnosis and treatment with combination of pre-operative embolization, local and extended curettage, local adyuvance and bone cement as described. At 18 months follow-up have found the patient remains without clinical or radiologic recurrence of CMF. We made a review of literature on chondromixoid fibroma emphasizing on pelvic bones compromise regarding diagnosis and management options.

Acrometástasis óseas, serie de casos y revisión de la literatura / Bone acrometástasis, case series and literature review

Resumen: Las acrometástasis se definen como metástasis óseas localizadas distales al codo y la rodilla. Su prevalencia es muy baja, aproximadamente el 0,1% de todas las metástasis óseas y se presentan en pacientes con enfermedad avanzada y son indicador de mal pronóstico. Hasta en el 10% de los casos se presentan como el primer signo de neoplasia oculta. Su forma de presentación clínica y radiológica es inespecífica, lo que genera retraso en su diagnóstico y tratamiento. La resonancia magnética es la imagen de elección para el diagnóstico. El tratamiento en la mayoría de los casos es paliativo. Presentamos cuatro pacientes con acrometástasis y una revisión de la literatura.

Abtract: Acrometastasis are defined as localized bone metastases distal to the elbow and knee. Its prevalence is very low, approximately 0.1% of all bone metastases and they present in patients with advanced disease and are considered indicators of poor prognosis. In up to 10% of cases are the first sign of undiagnosed neoplasia. Its clinical and radiological presentation is non-specific which generates delays in its diagnosis and treatment. Magnetic resonance is the image of choice for diagnosis. The treatment in most cases is palliative. We present four patients with acrometastasis and a review of the literature.

Cutaneous Collision Tumor Associated With Porocarcinomatous and Angiosarcomatous Components: A Potential Diagnostic Pitfall.

Sarcomatoid eccrine porocarcinoma (SEP) is a very rare malignancy including epithelial and mesenchymal components exhibiting pleomorphic cells, nuclear hyperchromasia, and high mitotic activity in both elements. To date, only 6 cases of this uncommon neoplasm have been reported, corresponding to women over 70 years of age with ulcerated skin lesions. The authors describe the first sarcomatoid eccrine porocarcinoma in a 75-year-old male patient with a right hallux lesion, presenting a collision tumor with a mixed population of epithelial cells and a spindle cell angiosarcomatous mesenchymal component each expressing distinct and nonoverlapping morphologic and immunohistochemical features of epithelial and mesenchymal differentiation.

Linfoma leptomeníngeo primario. Reporte de tres casos y revisión de la literatura / Primary leptomeningeal lymphoma. Report of three cases and review of the literature

El linfoma leptomeníngeo primario (LLMP) es una entidad con baja frecuencia de presentación, representa del 1% al 2,4% de los linfomas primarios del sistema nervioso central; las variedades histológica más observadas son el linfoma de la zona marginal tipo MALT, el linfoma B de célula grande difuso y el linfoma linfoblástico de células B. La localización y su extensión determinan las manifestaciones clínicas; en radiología se prefieren las imágenes con medios de contraste, ya que tienden a confundirse con meningiomas como la primera impresión diagnóstica y son la cirugía y los estudios de patología los que confirman el diagnóstico. La quimioterapia es la base del tratamiento en esta entidad, la radioterapia se deja como una opción secundaria. El propósito de este trabajo es presentar tres casos clínicos representativos de LLMP y las variantes por imágenes de radiología, la revisión enfocada de la literatura y el tratamiento de esta infrecuente patología.

Primary Leptomeningeal lymphmoma (PLML) is a low frequency neoplasm representing 1% to 2,4% of primary lymphomas of the central nervous system (CNS). The most frequent histological variety is the extranodal marginal zone lymphoma (MALT lymphoma), but other variants are reported such as diffuse large cell B-cell lymphoma (DLBCL). The location and extent determine the clinical manifestations. In radiology, images with contrast are preferred to difference from meningiomas which are the main differential diagnosis; nevertheless surgery and histology confirm the diagnosis. Chemotherapy is the mainstay of treatment and radiation therapy is a secondary alternative. The purpose of this paper is to present three cases of PML, the radiological variants and to conduct a focused literature review with treatment of this pathology.

Carcinoma anficrino de glándula mamaria. Reporte de un caso inusual / Breast amphicrine carcinoma. Report of an unusual case

Los tumores anficrinos de la glándula mamaria son lesiones duales muy poco frecuentes con diferenciación epitelial y neuroendocrina de una misma célula. Nosotros presentamos el caso de una mujer con masa en el seno derecho. El estudio histopatológico mostró un tumor maligno constituido por células pequeñas entremezcladas con algunas células con aspecto en anillo de sello. El uso de anticuerpos monoclonales mostró inmunoreactividad para marcadores epiteliales y neuroendocrinos en las células malignas. Estas características permitieron hacer el diagnóstico de un tumor anficrino basado en la expresión en la misma célula de marcadores epiteliales y neuroendocrinos. El diagnóstico diferencial debe realizarse con los tumores de colisión o con metástasis. La interpretación rigurosa de la inmunohistoquímica en las células neoplásicas en un tumor anficrino es útil para distinguir esta entidad de otras patológicas con características morfológicas similares.

Amphicrine tumours of the mammary gland are very rare dual lesions with epithelial and neuroendocrine differentiation in the same cell. We report the case of a woman with a mass in the right breast. The histopathology study showed a malignant tumour formed by small cells inter-mixed with some cells with a signet ring appearance. The use of antibodies showed immunoreactivity for epithelial and neuroendocrine markers in the malignant cells. These characteristics enable the diagnosis of an amphicrine tumour, based on the expression of epithelial and neuroendocrine markers in the same cell. The differential diagnosis must be made with collision tumours or with metastasis. The rigorous interpretation of the immunohistochemistry in the malignant cells in an amphicrine tumour is useful in order to distinguish this tumour from other diseases with similar morphological characteristics.

Primary diffuse large B-cell lymphoma associated with chronic osteomyelitis of the knee.

Diffuse large B-cell lymphoma (DLBCL) associated with chronic inflammation is a recently adopted category of DLBCL, which describes an aggressive B-cell lymphoma raised in the setting of non-immune chronic inflammation. Primary presentation of this subtype of DLBCL in bone is extremely rare. Here, we present the case of a 27 year old woman with DLBCL of the right distal femur, identified after a three-year history of chronic osteomyelitis. In this report, we describe the clinical and histopathologic features of this unusual presentation of DLBCL and discuss aspects relevant to diagnosis and treatment of this entity.

Primary intraocular inflammatory myofibroblastic tumor with anaplastic lymphoma kinase overexpression.

The human eye can be compromised by a variated spectrum of neoplasms and reactive processes. Here we present a rare case of a primary intraocular inflammatory myofibroblastic tumor (IMT) dependent on the sclera and choroid in a 31-year-old female. The knowledge surrounding IMTs, previously included in the category of inflammatory pseudotumors, has undergone dynamic changes in the past two decades. Here we review the characteristics of these tumors in the human eye and in the surrounding structures, and we describe the recent advances that allow molecular characterization of the neoplastic nature of this entity.

Primary esophageal meningioma: first literature report.

We have described a primary esophageal meningioma (MG) clinical case diagnosed in a 62-year-old woman; also, we review the literature about extracranial MGs. To our knowledge, this is the first case report of an extracranial MG occurring primarily in the esophagus. These are benign neoplasms reported classically in the central nervous system (CNS). The extrancranial MGs have histopathologic and inmunohistochemical features identical to those observed in CNS MGs; thus, the main diagnostic hurdle is to keep it in the differential for lesions occurring outside the CNS.

Primary malignant solitary fibrous tumor/hemangiopericytoma of the parotid gland / Tumor fibroso solitario maligno primario/hemangiopericitoma de la glándula parótida

Solitary fibrous tumor (SFT) was first described in the pleura by Lietaud in 1767; later in 1870, Wagner described the localized nature of this type of tumor and Klemperer and Rabin classified pleural tumors into two types: diffuse mesotheliomas and localized mesotheliomas. Recent years have seen the redefinition of this neoplasm, due to better technology; it is now proven that this neoplasm may have multiple different extrapleural origins including the head and neck regions. This diversity of locations is related to the particular mesenchymal histogenesis of SFT which allows its development from very unusual sites such as the salivary glands (SGs). In this particular site, this neoplasm is very infrequent and most of reported cases refer to benign disease, with just one case informed so far of primary malignant SFT (AU)

El tumor fibroso solitario (TFS) fue primeramente descrito en la pleura por Lietaud en 1767; posteriormente en 1870, Wagner describió la naturaleza localizada de este tipo de tumor y Klemperer y Rabin, en 1931, clasificaron los tumores pleurales en dos tipos: mesoteliomas difusos y mesoteliomas localizados. En los últimos años se ha redefinido esta neoplasia, debido a la mejora de las tecnologías; ahora se ha probado que puede tener múltiples y diferentes orígenes extra-pleurales, incluyendo la región de cabeza y cuello. Esta diversidad de localizaciones se relaciona con la histogénesis mesenquimal particular del TFS, que permite su desarrollo desde localizaciones muy inusuales tales como las glándulas salivares (GS). En esta localización particular este tumor es muy infrecuente, y muchos casos reportados se refieren a una enfermedad benigna, con un único caso informado hasta la fecha de TFS maligno primario (AU)

[Primary malignant solitary fibrous tumor/hemangiopericytoma of the parotid gland]. / Tumor fibroso solitario maligno primario/hemangiopericitoma de la glándula parótida

Solitary fibrous tumor (SFT) was first described in the pleura by Lietaud in 1767; later in 1870, Wagner described the localized nature of this type of tumor and Klemperer and Rabin classified pleural tumors into two types: diffuse mesotheliomas and localized mesotheliomas. Recent years have seen the redefinition of this neoplasm, due to better technology; it is now proven that this neoplasm may have multiple different extrapleural origins including the head and neck regions. This diversity of locations is related to the particular mesenchymal histogenesis of SFT which allows its development from very unusual sites such as the salivary glands (SGs). In this particular site, this neoplasm is very infrequent and most of reported cases refer to benign disease, with just one case informed so far of primary malignant SFT.

Primary yolk sac tumor of the urachus.

INTRODUCTION: Neoplasms originating from the urachus are rare. The most common urachal malignancy is adenocarcinoma, whereas extragonadal germ cell tumors, primarily of the urachus, are an extremely rare finding. OBJECTIVE: To describe a primary yolk sac tumor (YST) of the urachus in an adult. CASE REPORT: A 44-year-old woman presented with 6 months of pelvic pain associated with a sensation of progressive mass growth. At the time of tumor resection, the tumor was found to be attached by a pedicle to the dome of the bladder, with no injury to the adjacent organs. Pathological study showed a neoplasm with epithelioid cells, pseudocysts, a myxomatous background, and Schiller-Duval body formations. Immunohistochemistry stains showed positivity to AE1/AE3, α-1-fetoprotein, and α-1-antitrypsin and negativity to other markers. CONCLUSION: An unusual case of a YST in the urachus is presented. This is the first reported adult case based on the authors' bibliographic search.

Early age renal synovial sarcoma.

OBJECTIVE: We report a primary renal Synovial Sarcoma (SS) case and analyze its features. METHOD: A 15 year old male presented with left abdominal mass and weight loss. CT scan images showed a 13 cm mass located in the lower pole of the left kidney. Renal biopsy recognized an undifferentiated neoplasm, the immunohistochemistry suggesting the probability of neuroectodermic primitive tumor versus SS. Chemotherapy and radical nephrectomy were carried out. Pathological study showed a big multilobulated necrotic tumor 22 x 13 x 12.5 cm. Histopathological study demonstrated a neoplasm composed by immature cells. Currently, patient has survived 1,8 years. A structured bibliographical search was performed in the Medline, Imbiomed and Scielo databases. RESULTS: The final immunohistochemistry studies gave the diagnosis of poorly differentiated renal SS small cell variety. CONCLUSION: The renal SS is extremely infrequent, with less than 40 cases reported, of which this case reports the earlier age. These tumors, when located in the kidney, represent a great diagnostic challenge that requires adequate clinical, radiological, surgical, and pathological correlation for appropriate diagnosis and treatment.

Sarcoma sinovial renal en edad temprana / Early age renal synovial sarcoma

OBJECTIVE: We report a primary renal Synovial Sarcoma (SS) case and analyze its features.METHOD: A 15 year old male presented with left abdominal mass and weight loss. CT scan images showed a 13 cm mass located in the lower pole of the left kidney. Renal biopsy recognized an undifferentiated neoplasm, the immunohistochemistry suggesting the probability of neuroectodermic primitive tumor versus SS. Chemotherapy and radical nephrectomy were carried out. Pathological study showed a big multilobulated necrotic tumor 22x13x12.5 cm. Histopathological study demonstrated a neoplasm composed by immature cells. Currently, patient has survived 1,8 years.A structured bibliographical search was performed in the Medline, Imbiomed and Scielo databases.RESULTS: The final immunohistochemistry studies gave the diagnosis of poorly differentiated renal SS small cell variety.CONCLUSION: The renal SS is extremely infrequent, with less than 40 cases reported, of which this case reports the earlier age. These tumors, when located in the kidney, represent a great diagnostic challenge that requires adequate clinical, radiological, surgical, and pathological correlation for appropriate diagnosis and treatment (AU)

OBJETIVO: Describir un caso de Sarcoma Sinovial (SS) renal primario y realizar una revisión sobre este tema.MÉTODO: Paciente masculino de 15 años de edad, con masa abdominal izquierda y pérdida de peso. A quien se documentaron por imágenes una lesión de 13 cm de diámetro, localizada en el polo inferior del riñón izquierdo, por lo cual, se realizó una biopsia renal, en la que se evidenció un tumor maligno indiferenciado, cuyos estudios de inmunohistoquimica sugerían los diagnósticos de tumor neuroectodermico primitivo Vs SS. Con lo anterior, iniciaron quimioterapia y realizaron nefrectomía radical. Actualmente el paciente presenta una sobrevida de 1.8 años.RESULTADO: Se reconoció gran tumor renal izquierdo, de 22x13x12.5cm, multilobulado, con áreas de necrosis. Cuyo estudio histopatológico mostro una neoplasia maligna indiferenciada, compuesta por sabanas de células inmaduras. Los estudios de inmunohistoquimica permitieron concluir el diagnóstico de sarcoma sinovial renal pobremente diferenciado de variedad de células pequeñas. Estrategia de búsqueda de la literatura. Se realizó una búsqueda estructurada de la literatura, en las bases de datos Medline, Imbiomed y Scielo.CONCLUSIÓN: Los SS de localización renal son extremadamente infrecuentes, con menos de 40 casos reportados, del cual se presenta el caso informado a edad más temprana. Estos tumores cuando se localizan en el riñón, representan un gran reto diagnóstico que requiere de la adecuada correlación clínico, imagenologica, quirúrgica, y patológica para su adecuado diagnóstico y manejo (AU)

Testis T-cell lymphoma. Presentation of 2 cases and review.

OBJECTIVE: To present two clinical cases of testicular T cell lymphomas and perform a review of this condition. METHODS/RESULTS: Case 1. Forty-two year old male presenting with painful mass in the right testicle which appeared 2 months earlier. Testicular ultrasound showed diffuse increase in size of the testicle, with alteration in its echogenicity. The patient underwent orchidectomy, and based on histopathological and immunohistochemical tests, a peripheral nonspecific T cell lymphoma was diagnosed. Case 2. Forty-four year old male who presents with a 3 month history of left testicular enlargement without pain associated with reddish-brown macular lesions in the thigh and back and subsequent involvement of the right side of the scrotum. The ultrasonography showed testicles with increased size, with echogenicity altered diffusely. Left orchidectomy was performed and sent for histopathological and Immunophenotypic study which revealed a non-Hodgkin peripheral T cell lymphoma. CONCLUSION: T cell lymphomas involve the testis infrequently, which deserve special attention because of the poor prognosis and the need to make an appropriate diagnosis which could lead to a better therapeutic strategy.

Linfoma de células T en el testículo. Presentación de 2 casos clínicos y revisión de la literatura / Test T-cell lymphoma. Presentation of 2 cases and review

OBJETIVO: Presentar dos casos clínicos de linfoma de células T con compromiso testicular diagnosticados y realizar una discusión sobre este tema. MÉTODOS: Caso 1. Hombre de 42 años, con masa y dolor testicular derecho, de 2 meses de evolución. Cuya ecografía testicular evidencio aumento difuso del tamaño del testículo, con alteración de la ecogenicidad. Fue llevado a orquidectomía, diagnosticando con estudios de histopatología e inmunohistoquímica un linfoma de células T periférico inespecífico. Caso 2. Hombre de 44 años quien consulta por aumento de volumen del testículo izquierdo de 3 meses de evolución, con lesiones maculares cutáneas en muslo y espalda de color pardo rojizo, asociadas, con posterior compromiso del testículo derecho. La ecografía muestro testículos aumentados de tamaño, con alteración difusa de su ecogenicidad. Por lo anterior, realizan orquidectomía izquierda. Con el estudio histopatológico e inmunofenotípico, diagnóstico un linfoma no Hodgkin, T periférico no especificado. CONCLUSIÓN: Los linfomas de células T pueden comprometer los testículos en casos infrecuentes, que merecen especial atención debido al pobre pronóstico de esta enfermedad, y a la necesidad de realizar un adecuado diagnóstico que puede ayudar a implementar mejores estrategias terapéutica(AU)

OBJECTIVE: To present two clinical cases of testicular T cell lymphomas and perform a review of this condition. METHODS/RESULTS: Case 1. Forty-two year old male presenting with painful mass in the right testicle which appeared 2 months earlier. Testicular ultrasound showed diffuse increase in size of the testicle, with alteration in its echogenicity. The patient underwent orchidectomy, and based on histopathological and immunohistochemical tests, a peripheral nonspecific T cell lymphoma was diagnosed. Case 2. Forty-four year old male who presents with a 3 month history of left testicular enlargement without pain associated with reddish-brown macular lesions in the thigh and back and subsequent involvement of the right side of the scrotum. The ultrasonography showed testicles with increased size, with echogenicity altered diffusely. Left orchidectomy was performed and sent for histopathological and Immunophenotypic study which revealed a non-Hodgkin peripheral T cell lymphoma. CONCLUSION: T cell lymphomas involve the testis infrequently, which deserve special attention because of the poor prognosis and the need to make an appropriate diagnosis which could lead to a better therapeutic strategy(AU)

Neoplasia sólida pseudopapilar del páncreas: estudio clínico-patológico / Solid pseudopapillary tumor of the pancreas: clinical, histopathologic, and Immunohistochemic Analyses of 5 Cases

Introducción: La neoplasia sólida seudopapilar del páncreas (NSP) es un tumor poco común y se considera una entidad clínico-patológica bien definida. Afecta preferentemente al sexo femenino de la segunda y tercera décadas de la vida. En general, es de bajo potencial demalignidad y de crecimiento indolente. Con tratamiento adecuado, las recidivas son poco frecuentes y el pronóstico es excelente, aun en presencia de metástasis. La mortalidad debida al tumor es muy baja.Materiales y métodos: Se presentan cinco casos de NSP, encontrados en los archivos de patología del Instituto Nacional de Cancerología (INC) y de la Clínica Palermo de Bogotá, en un periodo de 11 años. Estos casos fueron analizados, clínica y patológicamente; así como,por técnicas de inmunohistoquímica.Resultados: Los cinco casos mostraron características clínicas y morfológicas similares a las descritas en la literatura. Dos de los casos sepresentaron en pacientes por encima de los 50 años, y uno de estos fue de sexo masculino. Uno presentaba metástasis hepáticas en el momento del diagnóstico, y el otro desarrolló metástasis, también en el hígado, en el transcurso de la enfermedad. No se evidenciaroncaracterísticas histopatológicas francas de malignidad en ninguno de los casos. Todos los pacientes en su último control médico se encontraban vivos, tres libres de enfermedad y dos con enfermedad metastásica.Conclusiones: Los resultados de inmunohistoquímica en este estudio favorecen el origen epitelial del tumor, como se acepta en la clasificación actual de la Organización Mundial de la Salud. En relación con la histogénesis, nuestro trabajo apoya el origen en la célula ductal. Para facilitar la comprensión del comportamiento biológico del tumor, esta neoplasia podría dividirse en cuatro grupos teniendo en cuenta la clínica, la histología y el potencial de malignidad.

Introduction: The solid-pseudopapillary neoplasm (PSN) is an uncommon tumor also considered a well defined clinical-pathological entity. This affects primarily to females in their second and third life decades. Generally it has a low malignancy potential and indolent growth. With the proper treatment the relapses are not frecuent and the prognosis is excellent even in the presence of metastasic stages. The mortality due to the tumor is really low. Methods and materials: Five cases of PSN founded in the archives of the National Cancer Institute (INC) and the Palermo’s Clinic of Bogotá in a eleven years are presented. These cases were analyzed both clinically and pathologically, and also by inmmunohistochemical technics. Results: All five cases showed similar clinical and morphological characteristics as described in the literature. Two of the cases were found on patients over 50 years-old, and one of this on a male patients. One presented liver metastasis during the diagnosis and other presented also liver metastasis during the disease development. None of the cases evidenciated histopathological features of real malignancy. All the patients before mentionated were alive during their last control appointment, three of them disease free and the remaining two with metastasis disease. Conclusion: The inmmunochemical results in this study are in favor of epithelial origin of tumour as it is accepted by the WHO´s current classification. In relation to histiogenesis our research supports the ductal cell origin. To easy the comprehension of the tumor behavior we could divide this type of neoplasm in four different groups according with clinic, histology and malignancy potential.