[719] Ovarian-Type Stroma in Renal Dysplasia, a Possible Pathogenic Link between Renal Dysplasia and Mixed Epithelial and Stromal Tumors of the Kidney

E Blochin, MA Greco, L Chiriboga, CH Hajdu. New York University School of Medicine, New York, NY

Background: Ovarian-type stroma is one of the pathognomonic features of mixed epithelial and stromal tumor of the kidney. ER/PR positivity has also been reported in the epithelial component of the tumor. Recently ovarian type stroma has been described in cases of non-tumorous or tumor-associated hydronephrosis among both females and males. We investigated the presence of ovarian-type stroma in cases of renal dysplasia and compared them to hydronephrosis.
Design: Archives from two institutions were searched within a five-year period. Cases with renal dysplasia and non-tumorous hydronephrosis were selected. In the renal dysplasia group there were three female and one male patients (4 cases; age range from 3 53 y.o). In the hydronephrosis group five patients were female and seven patients were male (12 cases; age range from 25 weeks gestational age to 60 y.o). One case of mixed epithelial and stroma tumor (MESTK) and two normal fetal kidneys were used as positive and negative controls. Representative sections were stained for ER and PR with subsequent evaluation of the nuclear labeling.
Results: Ovarian-type stroma surrounding dilated pelvic calyces was seen in 10/12 (83%) cases of hydronephrosis and in 4/4 (100%) cases of dysplastic kidneys around tubules. ER positivity was seen in both groups in all but one case of hydronephrosis (94%). PR labeling was present in only 6/12 (50%) cases of hydronephrosis and in 4/4 (100%) of cases with dysplasia. Interestingly, in all 4/4 (100%) cases of dysplasia the epithelium of the dysplastic tubules focally showed strong PR and in one case both ER and PR labeling. It is important to note that even in cases of hydronephrosis with secondary dysplastic changes, such as metaplastic cartilage and thick-walled vessels, the epithelial component was negative for ER/PR receptors. Two normal fetal kidneys did not stain for ER or PR. MESTK showed ER/PR positive stroma as expected.
Conclusions: We report the presence of ovarian-type stroma in renal dysplasia. In addition to the ovarian-type stroma, also seen in hydronephrosis, cases of dysplasia showd focal strong epithelial staining for ER and PR receptors. Our finding suggests that unlike the ovarian-type stroma in hydronephrosis which most likely represents a metaplastic response to mechanical forces, the presence of ovarian type stroma and positive epithelial staining for ER/PR in dysplastic kidney and MESTK may indicate a possible pathogenic link between the two entities.
Category: Genitourinary (including renal tumors)

Tuesday, March 10, 2009 1:00 PM

Poster Session IV # 134, Tuesday Afternoon