We present the case of a 64-year-old woman without any known allergies to drugs, who had smoked 20 cigarettes a day for more than thirty years, and with no other relevant history, who presented to our Department of Gastroenterology complaining of rectal bleeding and secondary ferropenic anemia with a hemodynamic repercussion. A colonoscopy was made to reveal the presence of a polypoid, submucous, ulcerated lesion in its vertex (8 cm from the anal margin) (Fig. 1).An endoanal ultrasound scan showed a heterogeneous mass located in the posterior wall of the rectum, approximately 7 cm in size, with no infiltration of perirectal fat (Fig. 2). A biopsy was made with a tru-cut needle, and the pathological study showed a proliferation of fusiform cells, with no mitoses or atypias, and strongly positive for the CD-117 marker; staining by other markers (CD-34, desmine, actine, and S-100) was negative, except for one slight ki-67-related positivity, less than 10%. An abdominal CAT scan revealed no metastases at all levels. With a preoperative diagnosis of rectal stromal tumor, the mass was removed by local excision with preservation of the rectum. The patient is currently in the eighteenth month of follow-up, and has no signs or symptoms of relapse, neither locally nor distally. DISCUSSIONThe incidence of GISTs is greatest in the fifth and sixth decades of life. Histologically they are made up of fusiform, epitheloid, or mixed cells. The diagnosis is confirmed by immuno-histochemical techniques, and by the expression of a

Introducción. La agenesia de pericardio, una entidad poco frecuente, en la mayoría de los casos presenta un curso asintomático. Sin embargo, ocasionalmente causa manifestaciones clínicas que pueden amenazar la vida del paciente. Caso clínico. Presentamos un caso de agenesia de pericardio que se detectó incidentalmente durante una cirugía de cierre de ductus y en el cual sus síntomas clínicos se podrían considerar secundarios al defecto. Comentarios. A pesar que este tipo de procedimientos están usualmente indicados en la corrección de defectos parciales en los cuales hay un mayor riesgo de muerte súbita debido a herniación y encarcelamiento, esta cirugía se realizó con base más en los síntomas del paciente que en su defecto anatómico.

Introduction: Hyperphosphataemia aggravates both parathyroid hyperplasia and PTH secretion in patients with chronic kidney disease (CKD). Hyperplasia is associated with decreases in calcium receptor expression (CaSR), vitamin D (VDR) and α-Klotho, inducing resistance of the parathyroid gland to respond both to treatment and to increases in FGF23. This study examined the possible epigenetic contributions of raised phosphorus to aggravate secondary hyperparathyroidism (SHPT) in patients with (CRD). Material and methods: The degree of methylation was compared by pyrosequencing of bisulfite in CpGrich sequences of the promoters in the CaSR, VDR, PTH and α-Klotho genes in parathyroid gland DNA from uremic rats fed a normal and high phosphorus diet. Results: The diet rich in phosphorus increased PTH expression and caused a marked reduction in the degree of methylation in the promoter of the PTH gene. In contrast, the promoter regions of the CaSR, VDR and α-Klotho genes did not show significant differences in the percentage of methylation between the two groups of rats. Thus, it was not the determining mechanism for the decrease of the expression of these genes observed in the SHPT. Conclusions: The epigenetic alterations induced by the phosphorus rich diet in SHPT, particularly the PTH gene hypomethylation, could contribute to the increases that occur in the synthesis and secretion of this hormone. The identification of the mechanisms involved would allow better treatments for SHPT to be designed in the early stages of CKD.