Relevancia de la medicina nuclear en el diagnóstico y tratamiento del paraganglioma maligno / Relevance of nuclear medicine in the diagnosis and treatment of malignant paraganglioma

Introducción: Los paragangliomas son tumores del tejido cromafín caracterizados por la síntesis o secreción de catecolaminas, en los que el tratamiento depende de su extensión y características funcionales. Dentro de la evaluación diagnóstica anatómica y funcional de este padecimiento, los métodos de imagen de medicina nuclear sobresalen por su utilidad. Caso clínico: Paciente con paraganglioma a nivel de la bifurcación de la aorta en quien el diagnóstico se realizó por estudios de laboratorio, imagenología y medicina nuclear. Se llevó a cabo centelleografía con un análogo de norepinefrina, la metayodobencilguanidina marcada radiactivamente (131I-MIBG), que demostró funcional y específicamente la presencia de tejido adrenérgico neoplásico y su extensión extratumoral. Complementariamente se efectuó tomografía por emisión de positrones fusionada con tomografía computarizada, utilizando un análogo radiactivo de la glucosa que localizó la actividad extratumoral a nivel óseo. Los estudios de medicina nuclear permitieron concluir que se trataba de un paraganglioma maligno con metástasis óseas. El tratamiento incluyó resección quirúrgica del tumor y ablación del tejido tumoral residual y de los focos metastásicos con radioterapia interna mediante 131I-MIBG. El tratamiento radioterapéutico fue posible dada la capacidad del tumor y las metástasis de concentrar el análogo hormonal radiactivo. Conclusiones: Ante casos de paragangliomas, además de la localización del tumor y la evaluación de las alteraciones bioquímicas, es indispensable la evaluación funcional que brinda la medicina nuclear para la realización de un diagnóstico y tratamiento adecuados.

BACKGROUND: Paragangliomas are neoplasms of the chromaffin tissue characterized by the synthesis and/or secretion of catecholamines. Their treatment depends on the extension and functional characteristics of the tumor. In this pathology, the anatomic and functional diagnostic evaluations provided by nuclear medicine imaging studies have significant usefulness. CLINICAL CASE: A 34-year-old male was diagnosed with a paraganglioma at the level of the aortic bifurcation by means of laboratory tests, imaging studies and nuclear medicine studies. Nuclear medicine was carried out with a scintigraphy with a norepinephrine analog, radioactive meta-iodo-benzyl-guanidine (131I-MIBG), which demonstrates functionally and specifically the presence of neoplastic adrenergic tissue and extratumoral extension. In addition, a positron emission tomography coupled with computed tomography with a radioactive analog of glucose locates the extratumoral activity at bone level. Nuclear medicine studies allow the diagnosis of a malignant paraganglioma with presence of bone metastasis. The therapy includes surgical removal of the tumor and ablation of residual malignant tissue and metastatic lesions by radiotherapy with 131I-MIBG. Radiotherapeutic treatment was possible due to the capacity of the tumor to uptake and to concentrate the radioactive hormonal analog. CONCLUSIONS: In cases of paraganglioma, in addition to the localization of the tumor and the evaluation of biochemical alterations, it is indispensable to obtain anatomic and functional evaluation provided by nuclear medicine studies in order to achieve appropriate diagnoses and treatment.

Angiodisplasia yeyunal como causa de sangrado de origen desconocido / Jejunal angiodysplasia as a cause of obscure gastrointestinal bleeding

BACKGROUND: Obscure gastrointestinal bleeding secondary to jejunal angiodysplasia is uncommon. Diagnostic approach is difficult and represents a challenge for the surgeon because of the inaccessibility of the small bowel for evaluation. When the diagnostic work-up has been completed and the bleeding source has not been found, it is mandatory to perform a surgical exploration with transoperative enteroscopy in order to locate the source of the hemorrhage and for further treatment. CASE REPORT: We report the case of a 24-year-old male with massive gastrointestinal bleeding secondary to jejunal angiodysplasia in whom an intraoperative enteroscopy was done to locate the source of bleeding and subsequently resect the affected small bowel. There are actually some non-surgical therapies for patients with high risk of complications. When patients' conditions are optimal, surgical resection is mandatory to avoid recurrence of future bleeding.