[Difficulties in the differential diagnosis of proteinuria during pregnancy].

Even during normal pregnancy, significant morphological, functional and hemodynamic changes take place in the kidneys, resulting in a slightly increased proteinuria. However, an abnormal increase, especially if accompanied by hypertension or impaired renal function, requires close maternal and fetal follow-up, as it may predict severe perina-tal complications. Differential diagnosis of proteinuria is diverse, and the primary consideration in clarifying the etiol-ogy is to differentiate between preeclampsia and other possible primary kidney disease. We list all the diseases on the etiological palette that may even mimic the symptoms of preeclampsia, making it difficult to make an accurate diag-nosis. In the case of a 31-year-old gravida, we review the differential diagnosis of progressive proteinuria observed during pregnancy. In addition to the diagnosis of postpartum preeclampsia, renal malignancy was confirmed. We are also looking for the answer whether malignant kidney cancer can be blamed for the clinical presentation that includes hypertension, progressive proteinuria.