[1601] Incidental Epithelial Neoplasms Identified in Medical Renal Biopsies

Josephine M Ambruzs, Stephen M Bonsib, Patrick D Walker, Nidia Messias. Nephropath, Little Rock, AR; University of Arkansas for Medical Sciences, Little Rock, AR

Background: Recent studies have emphasized that nephrectomy specimens removed for neoplasm should also be examined for medical renal disease. However there is little data on epithelial neoplasms in renal biopsies performed for medical reasons. Incidental epithelial neoplasms in renal medical biopsies are uncommon yet often pose a challenge in terms of subsequent clinical investigation and management. We report the largest series examining the frequency, spectrum, and clinical follow-up of incidental epithelial neoplasms identified in renal biopsies performed for medical kidney disease.
Design: We reviewed our experience of native and allograft kidney biopsies from 1/2005 to 6/2012. The biopsies were performed for medical reasons and in no case was the presence of a neoplasm suspected. All biopsies were reviewed by three pathologists, including a uropathologist. Relevant clinical data and follow-up was collected.
Results: 58 (0.17%) unsuspected epithelial neoplasms were identified including 2 in allografts. The mean age at biopsy was 62 years (range 28-85) and the male to female ratio was 2.6:1. All lesions were present on multiple levels with a mean size of 1.2 mm (range 0.2 – 5.2). Forty-four (76%) were low-grade papillary neoplasms including 19 adenomas. Renal cell carcinoma (RCC) was found in 9 samples (16%) of which 3 were papillary, 2 chromophobe, and 1 each of clear cell, clear cell papillary, acquired cystic kidney disease-associated and unclassified. Also found were 2 oncocytomas, 2 high-grade carcinomas favor metastasis, and 1 transitional cell carcinoma. Follow-up was available for 24 cases (mean 26.8 months, range 1–64) including 4 of the carcinomas. One third had radiologic studies including ultrasound, CT scan, PET scan or a combination of these modalities. Of those imaged, 3 identified a mass lesion that warranted surveillance or surgical management. This included a nephrectomy for papillary RCC and surveillance for 2 with acquired cystic kidney disease-associated RCC. One patient with metastatic disease died two months following biopsy.
Conclusions: 1.) This is the largest series of incidental epithelial neoplasms identified in renal biopsies for medical renal disease. 2.) A majority of tumors were low-grade papillary neoplasms. However high-grade tumors were also found. 3.) Tumor classification can be challenging because of the small quantity of tumor often present. 4.) Although uncommon, renal pathologists should consider consultation with a surgical pathologist since the presence of a neoplasm may necessitate a urologic workup.
Category: Kidney (does not include tumors)

Monday, March 4, 2013 1:00 PM

Poster Session II # 259, Monday Afternoon


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