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Nephrogenic Adenoma in a Urethral Diverticulum
Images in Clinical Urology Nephrogenic Adenoma in a Urethral Diverticulum Abhinav Sidana, Q.J. Zhai, and Ayman Mahdy Nephrogenic adenoma (NA) is a rare benign metaplastic lesion of the urothelial tract that arises as a response to injury and chronic inflammation. Although the most common site for NA is the bladder, it can occur in any part of urinary tract lined by urothelium. NA can mimic minor variants of urothelial cancer, clear cell adenocarcinoma, and prostate adenocarcinoma, making a combination of histologic examination and immunohistochemistry essential for diagnosis. We hereby report a rare case of nephrogenic adenoma arising in a urethral diverticulum. UROLOGY 80: e21– e22, 2012. © 2012 Elsevier Inc.
N
ephrogenic adenoma (NA) is an uncommon benign lesion of urothelial tract. It is a metaplastic response of urothelium to injury, characterized by tubules, cysts, and papillae lined by cuboidal to columnar epithelium interspersed in edematous and inflamed stroma.1 NA occurs more commonly in males (3:1) with the most common site being the bladder.1 Presentation in urethral diverticulum has been reported rarely.2,3 Immunohistochemically, NAs stain positive for cytokeratin 7, alpha-methylacylCoA racemase (AMACR) and PAX2, a renal transcription factor.4,5 Because NA has tendency to recur, patients require surveillance cystoscopy to detect early recurrences. We report a case of nephrogenic adenoma found in a urethral diverticulum in a 55-year-old female. The patient presented to our urology clinic for stress urinary incontinence, dysuria, and frequency for 1 year. Examination and imaging was consistent with urethral diverticulum (Fig. 1). The patient underwent uncomplicated diverticulectomy and midurethral sling placement. Pathology was suggestive of NA characterized by haphazard tubules and cysts in the inflamed stroma, as well as edema (Fig. 2). Differential diagnoses were urothelial carcinoma with small tubules and microcystic urothelial carcinoma. NA was confirmed by immunohistochemical stains (combination of AMACR and PAX2 positivity). Postoperatively, the patient reported resolution of her voiding symptoms. No recurrence was detected at 6 months’ follow-up.
Figure 1. Axial MRI section demonstrating 2.2 ⫻ 2.1-cm fluid collection around urethra suggestive of urethral diverticulum. Filling defect was noticed (arrow).
References
Financial Disclosure: The authors declare that they have no relevant financial interests. From the Section of Voiding Dysfunction and Female Urology, Division of Urology, Department of Surgery, University of Cincinnati College of Medicine, Cincinnati, OH; and Department of Pathology, University of Cincinnati College of Medicine, Cincinnati, OH Reprint requests: Abhinav Sidana, M.D., Division of Urology, Department of Surgery, University of Cincinnati College of Medicine, 231 Albert Sabin Way, Cincinnati, OH 45219. E-mail: [email protected] Submitted: March 17, 2012, accepted (with revisions): April 17, 2012
1. Amin W, Parwani AV. Nephrogenic adenoma. Pathol Res Pract. 2010;206:659-662. 2. Greco A, Giammò A, Tizzani A. [Nephrogenic adenoma arising from an urethral diverticulum in a female. Report of a case and review of the literature]. Minerva Urol Nefrol. 1999;51:39-43. 3. Young RH. Pseudoneoplastic lesions of the urinary bladder and urethra: a selective review with emphasis on recent information. Semin Diagn Pathol. 1997;14:133-146. 4. Gupta A, Wang HL, Policarpio-Nicolas ML, et al. Expression of alpha-methylacyl-coenzyme A racemase in nephrogenic adenoma. Am J Surg Pathol. 2004;28:1224-1229. 5. Kunju LP. Nephrogenic adenoma: report of a case and review of morphologic mimics. Arch Pathol Lab Med. 2010;134:14551459.
© 2012 Elsevier Inc. All Rights Reserved
0090-4295/12/$36.00 http://dx.doi.org/10.1016/j.urology.2012.04.030
e21
Figure 2. (A) Hematoxylin and eosin staining demonstrating tubulocystic pathology, with inflammatory cells and edema. Tubules resemble renal tubules at low powers. (B) AMACR immunostaining of cytoplasmic granules in tubular cells. (C) PAX2 staining of nuclear antigens in tubular cells.
e22
UROLOGY 80 (2), 2012
N
ephrogenic adenoma (NA) is an uncommon benign lesion of urothelial tract. It is a metaplastic response of urothelium to injury, characterized by tubules, cysts, and papillae lined by cuboidal to columnar epithelium interspersed in edematous and inflamed stroma.1 NA occurs more commonly in males (3:1) with the most common site being the bladder.1 Presentation in urethral diverticulum has been reported rarely.2,3 Immunohistochemically, NAs stain positive for cytokeratin 7, alpha-methylacylCoA racemase (AMACR) and PAX2, a renal transcription factor.4,5 Because NA has tendency to recur, patients require surveillance cystoscopy to detect early recurrences. We report a case of nephrogenic adenoma found in a urethral diverticulum in a 55-year-old female. The patient presented to our urology clinic for stress urinary incontinence, dysuria, and frequency for 1 year. Examination and imaging was consistent with urethral diverticulum (Fig. 1). The patient underwent uncomplicated diverticulectomy and midurethral sling placement. Pathology was suggestive of NA characterized by haphazard tubules and cysts in the inflamed stroma, as well as edema (Fig. 2). Differential diagnoses were urothelial carcinoma with small tubules and microcystic urothelial carcinoma. NA was confirmed by immunohistochemical stains (combination of AMACR and PAX2 positivity). Postoperatively, the patient reported resolution of her voiding symptoms. No recurrence was detected at 6 months’ follow-up.
Figure 1. Axial MRI section demonstrating 2.2 ⫻ 2.1-cm fluid collection around urethra suggestive of urethral diverticulum. Filling defect was noticed (arrow).
References
Financial Disclosure: The authors declare that they have no relevant financial interests. From the Section of Voiding Dysfunction and Female Urology, Division of Urology, Department of Surgery, University of Cincinnati College of Medicine, Cincinnati, OH; and Department of Pathology, University of Cincinnati College of Medicine, Cincinnati, OH Reprint requests: Abhinav Sidana, M.D., Division of Urology, Department of Surgery, University of Cincinnati College of Medicine, 231 Albert Sabin Way, Cincinnati, OH 45219. E-mail: [email protected] Submitted: March 17, 2012, accepted (with revisions): April 17, 2012
1. Amin W, Parwani AV. Nephrogenic adenoma. Pathol Res Pract. 2010;206:659-662. 2. Greco A, Giammò A, Tizzani A. [Nephrogenic adenoma arising from an urethral diverticulum in a female. Report of a case and review of the literature]. Minerva Urol Nefrol. 1999;51:39-43. 3. Young RH. Pseudoneoplastic lesions of the urinary bladder and urethra: a selective review with emphasis on recent information. Semin Diagn Pathol. 1997;14:133-146. 4. Gupta A, Wang HL, Policarpio-Nicolas ML, et al. Expression of alpha-methylacyl-coenzyme A racemase in nephrogenic adenoma. Am J Surg Pathol. 2004;28:1224-1229. 5. Kunju LP. Nephrogenic adenoma: report of a case and review of morphologic mimics. Arch Pathol Lab Med. 2010;134:14551459.
© 2012 Elsevier Inc. All Rights Reserved
0090-4295/12/$36.00 http://dx.doi.org/10.1016/j.urology.2012.04.030
e21
Figure 2. (A) Hematoxylin and eosin staining demonstrating tubulocystic pathology, with inflammatory cells and edema. Tubules resemble renal tubules at low powers. (B) AMACR immunostaining of cytoplasmic granules in tubular cells. (C) PAX2 staining of nuclear antigens in tubular cells.
e22
UROLOGY 80 (2), 2012