Urosepsis as a presenting symptom of renomedullary interstitial cell tumor causing renal obstruction.

Abstract

A 25 year old woman presented with a one day history of severe right flank pain and high fever. She had no previous history of urinary tract infection. Her medical history was negative. On admission blood pressure was 90/60 and heart rate 124/min. Blood tests revealed 16,900 leukocytes with 90.7% neutrophils and serum creatinine of 1.13. Urinalysis showed trace leukocytes and a moderate amount of erythrocytes. She was pale and looked ill, and had a severe right flank tenderness. Computed tomography scan without contrast r enomedullary interstitial cell tumors were first described in 1972 and were called medullary fibromas. They were considered to be benign fibroblastic tumors. However, histopathological studies have shown that the spindle cells found throughout the basophilic loose stroma constitute a diagnostic pattern for renomedullary interstitial cell tumor and not for fibroma. Usually small benign tumors are a frequent incidental finding at autopsy. On the other hand, large tumors are very rare and only 10 cases of symptomatic renomedullary media delineated a severe right hydronephrosis with a 5 cm mass in the renal pelvis. No calculi were detected in the kidney or ureter. The patient underwent a percutaneuos right tube nephrostomy with good urinary drainage and her clinical condition improved. A subsequent nephrostogram revealed a markedly dilated pelvicalyceal system due to 5 cm mass in the renal pelvis descending to the proximal ureter [Figure A]. Right ureteroscopy was performed and biopsies were obtained from a huge smooth mass in the renal pelvis. Histological examination showed normal urothelial lining with a slightly fibrotic lamina propria without evidence of malignancy. Right pyelotomy was performed through a flank incision and the mass was completely excised. Macroscopically a 5 cm whitish gray glistening tumor was found. Histological examination revealed a tumor composed of spindle cells in a loose basophilic matrix containing interlacing delicate bundles of collagen fibers. CD34, desmin, caldesmon, smooth muscle actin, s-100 were negative [Figure B]. A diagnosis of renomedullary interstitial cell tumor was established. The suggested origin of the cells was medullary interstitial cells.