PMC3350100_01
Macroscopic findings showing squamous metaplasia of renal pelvis and abrupt sparing of pyramidal zones. Insert lower left shows metaplastic process stops at transition zone.
CRIM.UROLOGY2012-242780.001.jpg
PMC3350100_01_CRIM.UROLOGY2012-242780.001.jpg
fig1
The surface of the renal pelvis showed a pearly gray-to-silver sheen with foci of black discoloration (Figure 1). The squamous metaplastic process appeared to end abruptly at the juncture of the pelvis and minor calyceal system (insert, Figure 1).
Histologic findings at 40x (a) show H&E stained transition zone between renal parenchymal stroma (top) and renal pelviceal stroma (bottom); (b) shows metaplastic epithelial component is negative for CK5+; (c) shows CD7+ positive staining of metaplastic component; (d) shows extensive desquamative squamous metaplasia over densely collagenized pelviceal stroma.
CRIM.UROLOGY2012-242780.002.jpg
PMC3350100_01_CRIM.UROLOGY2012-242780.002.jpg
fig2
Histologic features are seen in Figure 2(a) (H&E stain). Metaplastic changes in the urothelium of the renal pelvis stained CK5+/CK7- (Figure 2(b) insert), with abrupt transformation to simple cuboidal epithelium (lining the minor calyx) which stained CK5-/CK7+ (Figure 2(c) insert); CK7 would have been the usual cytokeratin found in the collecting ducts. Additionally, at the juxtaposition of these two surfaces, we see changes in the underlying stroma with the transitional loss of the ureteral muscularis mucosa with transition to underlying renal parenchyma in the pyramidal zone of the minor calyx (Figure 2(d) insert).