Idiopathic retroperitoneal fibrosis presented as an abdominal mass and nephrotic syndrome

Abstract

We present a 30-year-old male patient who was initially diagnosed as minimal change nephrotic syndrome, 5 years later, the patient developed a localized form of idiopathic retroperitoneal fibrosis (IRF). An elevated ESR and concomitant nephrotic syndrome in the patient suggested the immunologic nature of IRF, IRF has been reported in association with collagen diseases and rarely with proliferative and nonproliferative glomerulopathies. To our knowledge, the association between minimal change lesion (MC) and IRF has not been reported. Furthermore, the fact that IRF presented itself as an abdominal mass and lacked systemic symptoms was also unusual.

Fig. 1.

Light microscopy shows a slight increase in size of the glomeruli but otherwise no abnormal findings are observed (H&E ×100).

Fig. 2.

Postcontrast CT scan reveals that the mass is a mixture of highly attenuated solid portions and low-attenuated necrotic portions. The outer margin of the mass is discrete and no intra-abdominal lymph node enlargement is observed.

Fig. 3.

Anintravenous urography, the right kidney is rotated upward on the frontal plane, but no abnormal finding is seen in the shape of calyx, pelvis and ureter, nor the excretory function of both kidneys.

Fig. 4.

A cross surface of the removed mass shows it to be a fairly well-circumscribed mass with fascicles of fibrous tissue and two areas of cystic change.

Fig. 5.

Photomicrographs of the mass show irregular fibrous bands and scattered inflammatory cell collections (H&H ×100).

Fig. 6.

At a higher magnification of the fibrous mass, the inflammatory cells consist of lymphocytes and some plasma cells (H&E ×350).