Normal Renal Parenchyma Simulating Tumor

Abstract

The initial enthusiasm for angiographic differentiation of renal tumor and cyst has matured into an attempt to differentiate a broad spectrum of medical and surgical lesions of the kidney. Pathologic lesions that mimic tumor, such as xanthogranulomatous pyelonephritis, abscesses, tuberculosis, and fibrolipomatosis, have been described with increasing frequency (1, 2, 6, 7). Marginal lobulations of the kidney, which may mimic tumor in normal kidneys, have been reported (4). Mass lesions of hypertrophied parenchyma or local nodular areas of residual normal parenchyma in diseased kidneys represent another form of pseudo-tumor. Unnecessary surgery, which could have been avoided by proper interpretation of the renal angiogram, has been performed in such instances. Case Reports Case I: A 47-year-old female was admitted to The Bronx-Lebanon Hospital Center with left flank pain and pyuria. There was an antecedent history of pyelonephritis extending back to childhood. A urogram revealed atrophic pyelonephritis bilaterally, focal on the left, general on the right. Retrograde pyelography confirmed the findings and defined the extent of calyceal involvement (Fig. 1, A). A selective right renal arteriogram revealed marked uniform loss of cortex with normal vessels supplying a nodule of parenchyma laterally (Fig. 1, B). The nodule appeared to represent a focal area of parenchyma which escaped the full effect of atrophy and destruction (Fig. 1, C). Case II: A 72-year-old male was admitted to The Bronx-Lebanon Hospital Center with gross hematuria later found to be due to a bladder neoplasm. The initial urogram was unsatisfactory. A drip urogram revealed a nodule on the lateral aspect of the left kidney which manifested the same density as the remainder of the kidney (Fig. 2, A). Arteriography was suggested to exclude tumor. Normal vessels supplied the area (Fig. 2, B), which was a nodule of cortex demarcated by a retracted scar (Fig. 2, C). Normal calyces indicated that the scar was secondary to a healed infarct. Case III: At cystoscopy in a 62-year-old male with left flank pain and hematuria, blood was noted to flow from the left ureteral orifice. Retrograde pyelography revealed displacement of the upper pole calyces (Fig. 3, A). Selective left renal arteriography showed slight curvilinear displacement of interlobar arteries (Fig. 3, B). No abnormal vessels were noted. Late films revealed a dense “blush” in a 1 1∕2 cm nodule which produced the defect noted in the pyelogram (Fig. 3, C). Even though no tumor vessels were observed, a neoplasm could not be excluded. Left nephrectomy was performed. The pathologic specimen showed no evidence of tumor. The nodule was normal parenchyma, a prominent column of Bertin adjacent to the renal sinus.