402 Arch Bronconeumol. 2005;41(7):402-3 Introduction Thymolipoma is an uncommon benign tumor of the anterior mediastinum. 1 The cause is disputed, but the most accepted theory of pathogenesis is replacement of the thymus by mature adipose tissue. The tumor grows slowly and can become large. Although most patients with a thymolipoma are asymptomatic, local nonspecific symptoms may present or the tumor may be associated with parathymic syndromes such as myasthenia gravis, hyperthyroidism, lymphangiomas, aplastic anemia, chronic lymphocyte leukemia, and Hodgkin disease. 2 The tumor may resemble cardiomegaly in a chest x-ray and is difficult to distinguish from other mediastinal tumors. We describe an adult who presented with left-sided pleural pain with a long duration and x-ray findings indicative of cardiomegaly, but the definitive diagnosis was giant thymolipoma. Case Description A 26-year-old man with no prior medical history of interest was transferred to the emergency room with left-sided pleural pain of 3 months duration but no other associated symptoms. The only finding of interest in the physical examination was the complete absence of vesicular breath sounds in the left side of the chest. The laboratory findings were normal. Simple posteroanterior chest x-ray identified a large mass in the left side of the chest, located in the pleural cavity and anterior mediastinum. The initial diagnosis was cardiomegaly. CASE REPORTS Giant Thymolipoma C. Roque, P. Rodríguez, C. Quintero, N. Santana, M. Hussein, and J. Freixinet Servicio de Cirugía Torácica, Hospital Universitario de Gran Canaria Dr. Negrín, Las Palmas de Gran Canaria, Spain. Thymolipoma is an uncommon benign tumor (accounting for 2% to 9% of thymus tumors). We present the case of a 26-year-old man who sought medical attention for left-sided pleural pain of 3 months duration. Computed tomography showed a mass in the left side of the chest occupying both the anterior mediastinum and the left pleural cavity. This mass caused lung collapse and mediastinal shift. Magnetic resonance imaging revealed a large fatty tumor and transthoracic biopsy with radiological guidance confirmed the diagnosis. The tumor was resected through a left thoracotomy. No postsurgical complications occurred and the histopathological diagnosis was thymolipoma. Key words: Thymolipoma. Mediastinum. Mediastinal tumor. Timolipoma gigante El timolipoma es una neoplasia benigna poco frecuente (constituye del 2 al 9% de los tumores tímicos). Se presenta el caso de un varón de 26 años de edad que consultó por un dolor pleurítico izquierdo de 3 meses de evolución. La tomo- grafía computarizada evidenció una masa torácica izquier- da que ocupaba tanto el mediastino anterior como la cavi- dad pleural izquierda y provocaba un colapso pulmonar y una desviación mediastínica. La resonancia magnética puso de manifiesto una gran tumoración de origen graso y la biopsia transtorácica con control radiológico confirmó su etiología. Se intervino al paciente mediante toracotomía iz- quierda y se realizó una exéresis en bloque de la tumora- ción. El curso clínico postoperatorio transcurrió sin compli- caciones y el diagnóstico histopatológico fue de timolipoma. Palabras claves: Timolipoma. Mediastino. Tumor de mediastino. Correspondence: Dr. P. Rodríguez. Servicio de Cirugía Torácica. Hospital Universitario de Gran Canaria Dr. Negrín. Barranco de la Ballena, s/n. 35010 Las Palmas de Gran Canaria. Las Palmas. España. E-mail: prosu2001@yahoo.es Manuscript received September 2, 2004. Accepted for publication September 20, 2004. Figure 1. Chest magnetic resonance image showing a large mass in left side of the chest. The mass is isointense to fat and occupies the pleural cavity and the anterior mediastinum, causing complete collapse of the lung.