Retroperitoneal fibrosis associated with immunoglobulin IgG4-related disease in the differential diagnosis in retroperitoneal tumors. Case report. / Fibrosis retroperitoneal nodular asociada a IgG4 como diagnóstico diferencial en tumores retroperitoneales. Reporte de un caso.

The patient was a 55-year-old woman with a 4-month history of pain in left flank that irradiated to the lumbar region. Computed tomography revealed a cystic tumor in the retroperitoneal region that compresses the ureter and left renal pelvis in contact with pancreatic body and tail. Surgery was performed and the definitive pathological report diagnosed nodular retroperitoneal fibrosis associated with IgG4; Ki67-positive in germinal centers (5%) and IgG4-positive (40 plasma cells in 3 fields of 40x) by immunohistochemistry. Retroperitoneal fibrosis is a rare disease, that develops gradually and has an excellent response to steroid management. Surgical treatment is reserved for cases that compromise adjacent structures. Thus, identifying it when studying a retroperitoneal tumor leads to better prognosis and survival.

Fibrosis retroperitoneal nodular asociada a IgG4 como diagnóstico diferencial en tumores retroperitoneales. Reporte de un caso / Retroperitoneal fibrosis associated with immunoglobulin IgG4-related disease in the differential diagnosis in retroperitoneal tumors. Case report

Paciente de 55 años de edad con cuadro de dolor en flanco izquierdo irradiado a región lumbar de 4 meses de evolución, con tomografía axial computarizada que reporta tumoración quística en región retroperitoneal que comprime uréter y sistema pielocaliceal izquierdo en contacto con cuerpo y cola de páncreas. Es intervenida quirúrgicamente y se encuentra en reporte patológico definitivo fibrosis retroperitoneal nodular asociada a IgG4; con Ki67 positivo en centros germinales (5%) e IgG4 positivo (40 células plasmáticas en 3 campos de 40x) por inmunohistoquímica. La fibrosis retroperitoneal nodular es una enfermedad poco frecuente, de evolución paulatina con excelente respuesta al manejo con esteroides. El tratamiento quirúrgico se reserva para casos que comprometen estructuras adyacentes, por lo que el identificarlo al estudiar una tumoración retroperitoneal conlleva un mejor pronóstico y sobrevida

The patient was a 55-year-old woman with a 4-month history of pain in left flank that irradiated to the lumbar region. Computed tomography revealed a cystic tumor in the retroperitoneal region that compresses the ureter and left renal pelvis in contact with pancreatic body and tail. Surgery was performed and the definitive pathological report diagnosed nodular retroperitoneal fibrosis associated with IgG4; Ki67-positive in germinal centers (5%) and IgG4-positive (40 plasma cells in 3 fields of 40x) by immunohistochemistry. Retroperitoneal fibrosis is a rare disease, that develops gradually and has an excellent response to steroid management. Surgical treatment is reserved for cases that compromise adjacent structures. Thus, identifying it when studying a retroperitoneal tumor leads to better prognosis and survival