Primary alveolar rhabdomyosarcoma of bone. / Rabdomiosarcoma alveolar primario de hueso. Reporte de un caso y revisión de la literatura.

INTRODUCTION: Rhabdomyosarcoma (RMS) is a malignant solid tumor of mesenchymal origin. It is the most com mon soft-tissue sarcoma in childhood and adolescence. 65% of cases are diagnosed before the age of 6. Histological subtypes include embryonal, alveolar, pleomorphic, and fused-cell RMS. The embryo nal subtype is more frequent in children, while the alveolar one is more frequent in adolescents and adults. OBJECTIVE: To describe the clinical presentation of primary alveolar rhabdomyosarcoma in a schoolgirl. CLINICAL CASE: 7-year-old schoolgirl with one-month history of progressive pain in her left thigh. X-ray shows a lytic lesion in the left femur diaphysis. A study was performed with 2 biopsies, immunohistochemistry, and PAX-FOXO1 studies which were compatible with alveolar RMS. Con clusion: Primary alveolar rhabdomyosarcoma of the bone is rare, but it should be considered within the differential diagnosis of primary small-round-blue cell bone tumors. Despite presenting a poor prognosis cytogenetic, this type of tumor seems to have better biological behavior, which for a successful treatment makes necessary to have a high index of suspicion in order to install a multimodal therapy in the context of a national protocol.

Actinomicosis torácica por actinomyces odontolyticus / Pulmonary actinomycosis by actinomyces odontolyticus. A case report and review of the literature

Introduction: Actinomycosis is an infrequent infection caused by bacteria from Actinomyces genus that manifests as a chronic, suppurative and progressive disease. Thoracic actinomycosis occurs in 18 percent of the cases, and infection by Actinomyces odontolyticus is even less frequent. The clinical presentation mimics tuberculosis or neoplastic processes. Clinical case: We report the case of a 75 years old man with COPD and Diabetes Mellitus type 2. He was referred to our clinic presenting a history of chronic cough, progressive dyspnea, fever and occasional bouts of haemoptysis. Chest radiograph showed a peripherally-located parenchymal opacity in the upper right lobe with over a year of evolution that later became a cavitary mass mimicking bronchogenic neoplasm or tuberculosis. The patient underwent bronchoscopic and CT- guided biopsy that showed necrosis and inflammatory cells. In the culture of cavitary fluids grew Actinomyces odontolyticus. We concluded that it was a thoracic actinomycosis. Penicillin 20 million units per day for six weeks was given, followed by oral amoxicillin for 6 months with good clinical and radiological response. Comments: To our knowledge this is the first report in Chile of lung infection caused by Actinomyces odontolyticus. Actinomycosis is a great masquerader, in this case we made the diagnosis with a fluid culture. This microorganism must be considered in the differential diagnostic in cavitary lung diseases.

Introducción: La actinomicosis pulmonar es una infección infrecuente causada por una bacteria del género Actinomyces, se manifiesta como un proceso crónico, supurativo de curso progresivo, el compromiso torácico ocurre aproximadamente en el 18 por ciento de los casos y la infección por Actinomyces odontolyticus es aun menos frecuente. Caso clínico: Se presenta el caso de un paciente hombre de 75 años de edad con antecedentes de EPOC y Diabetes Mellitus tipo 2, que fue derivado a nuestra clínica por cursar con una reagudización infecciosa persistente caracterizada por tos productiva, disnea progresiva,fiebre y episodios reiterados de hemoptisis de escasa cuantía. En la radiografía de tórax y tomografia computada, se detectaron opacidades mal definidas en lóbulo superior derecho de un año de evolución, que posteriormente se transforman en una masa cavitada adyacente a la pared toráxica simulando una neoplasia broncogénica o tuberculosis. El paciente fue sometido a fibrobroncoscopía realizándose biopsia y punción transbronquial. Posteriormente se efectuó biopsia por punción trans-toráxica guiada radiológicamente y en una muestra de tejido de aspecto necrótico y en líquido de la cavidad enviado a cultivo se pudo aislar Actinomyces odontolyticus. Concluyéndose que se trataba de una actinomicosis tóraco-pulmonar, se procedió a tratar con penicilina sódica 20 10(6) UI/dia por seis semanas y después se programó tratamiento por seis meses con amoxicilina vía oral, con buena respuesta clínica y radiológica. Comentarios: En nuestro conocimiento esta sería la primera comunicación en Chile de una lesión pulmonar producida por Actinomyces odontolyticus. La Actinomicosis, es un gran imitador, en este caso realizamos el diagnóstico con cultivo de líquido por punción. Este microorganismo debe ser considerado en el diagnóstico diferencial de lesiones cavitarias pulmonares.