Recurrent gastrointestinal bleeding caused by a jejunal GIST We report a 39 years old male with a history of three episodes of hematochezia and severe anemia. Upper and lower gastrointestinal endoscopies were normal. Labeled red blood cell scan, selective angiography and abdominal CAT scan identifi ed a bleeding solid jejunal mass that was excised. The pathological report showed a gastrointestinal stromal tumor measuring 6 cm in diameter, with medium malignancy (two mitoses in 50 high magnifi cation fi elds). Immunohistochemistry showed that it was CD 117 positive and CD 34 negative, smooth muscle actin and S 100 were positive in the malignant cells. After eight years of follow up, the patient is disease free.

Neo-adjuvant treatment with imatinib for a rectal gastrointestinal stromal tumor Background: Rectal gastrointestinal stromal tumors (GIST) are rare. Neo-adjuvant therapy with imatinib is recommended for locally advanced or non-resectable tumors. Case report: We report a 63 years old woman with a malignant GIST located in the recto-vaginal septum which was initially considered nonresectable. The patient was treated with imatinib as induction therapy for three months. After this lapse the tumor was successfully excised using an endo-anal approach. Due to a tumor size over 5 cm and the presence of 13 mitoses per 50 high power fields, two bad prognostic factors, treatment with imatinib was maintained for 15 months after surgery. After 20 months of follow up, the patient is free of disease with complete fecal continence and with an adequate sexual life. Secondary effects of imatinib are gradually subsiding

RESUMENEl 70% de los casos de la Enfermedad de Castleman (EC) se presentan como masas ganglionares que afectan el mediastino. El compromiso del tubo digestivo de la EC es muy raro. Se presenta un caso excepcional de EC ubicado en el espesor de la pared rectal que fue sometida a una resección anterior baja con la sospecha clínica de una endometriosis. El estudio histopatológico demostró una EC del tipo hialinovascular y la paciente está asintomática luego de 2 años de seguimiento. Se reconoce una variedad hialinovascular de la EC, que es generalmente asintomática y que se presenta como lesiones solitarias. La variedad de células plasmáticas de la EC, en cambio, tiende a ser multicéntrica, con compromiso sistémico y en el 18% de los casos puede ocurrir la transformación a un linfoma maligno o un sarcoma de Kaposi. El diagnóstico preoperatorio de la EC localizada en el abdomen o en la pelvis es muy difícil. Como el estudio por imágenes no permite descartar un tumor maligno, habitualmente se requiere una exploración quirúrgica con el fin de realizar una resección completa o, al menos, una biopsia incisional diagnóstica. Las lesiones solitarias que son resecadas en forma completa tienen un pronóstico excelente y no hay casos de recidiva publicados. La variedad multicéntrica de la EC, en cambio, tiene un pronóstico reservado y requiere de un manejo multidisciplinario.PALABRAS CLAVE: Enfermedad de Castleman, hiperplasia linfática gigante, hiperplasia angiofolicular, variedad hialino-vascular. SUMMARYCatleman disease usually presents as mediastinal lymph nodes and gastrointestinal involvement is exceptional. We report a 49 years old female with a vascularized mass located in the sigmoid colon. The mass was excised and the pathological study showed a Castleman disease, hyaline vascular variety. The patient is free of symptoms after two years of follow up. This variety of Castleman disease usually presents as solitary asymptomatic masses and if it is completely excised, the prognosis is good.