[985] Nephrogenic Adenoma: An Immunohistochemical Study

William Quinones, Amy Ziober, Yuan Yao, Zhanyong Bing. Hospital of University of Pennsylvania, Philadelphia, PA

Background: Nephrogenic adenoma (NA) is a rare benign lesion commonly occurring in the urinary bladder. NA may be derived from detached renal tubular cells implanting along the urothelial tract in previously injured areas. NA can be confused with lesions with papillary architectures including urothelial papilloma, papillary urothelium neoplasm with low malignant potential, and low-grade papillary urothelial carcinomas. NA involving deep lamina propria and/or superficial muscle can mimic metastatic prostatic adenocarcinoma, urothelial carcinoma with bland histology including nest variant of urothelial carcinoma and microcystic urothelial carcinoma, and clear cell adenocarcinoma.
Design: Twenty one cases of NAs were retrieved from the archives of hospital of the University of Pennsylvania. Immunohistochemistry for PAX8, p63, CK903 and PSA were performed on routine tissue sections according to the standard immunohistochemistry protocols. Intensity of the nuclear staining for PAX8 and p63 and the cytoplasmic staining for CK903 and PSA were evaluated and graded as 0, 1+, 2+, and 3+. Extent of staining was assigned as focal (<25%), nonfocal (25% to 75%), or diffuse (>75%).
Results: PAX8 showed diffuse moderate to strong (2+/3+) nuclear staining in all of NAs (n=21) and negative in the normal urothelium (n=15). Nuclear staining for p63 was not seen in any case of NAs examined (n=19) and was diffuse and strong (3+) in the normal urothelium (n=14). High molecular weight keratin CK903 showed weak (1+) diffuse staining in all of the nephrogenic adenomas examined (n=19) and diffuse and strong positivity in the normal urothelium (n=16). PSA staining was negative in both of the NAs (n=21) and normal urothelium (n=16).
Conclusions: We evaluated a panel of immunohistochemical markers in 21 cases nephrogenic adenomas. A panel composed of PAX8, p63 and PSA appears to be sensitive and specific in differentiating NA from its mimics of urothelial and prostatic origins.
Category: Genitourinary (including renal tumors)

Monday, March 19, 2012 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 157, Monday Morning


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