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Year : 2010  |  Volume : 53  |  Issue : 1  |  Page : 195-197
Neuroendocrine tumor in horseshoe kidney

1 Department of Urology, All India Institute of Medical Sciences, New Delhi-110 029, India
2 Department of Pathology, All India Institute of Medical Sciences, New Delhi-110 029, India

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Date of Web Publication19-Jan-2010

How to cite this article:
Anand A, Seth A, Singh M K, Gupta C. Neuroendocrine tumor in horseshoe kidney. Indian J Pathol Microbiol 2010;53:195-7

How to cite this URL:
Anand A, Seth A, Singh M K, Gupta C. Neuroendocrine tumor in horseshoe kidney. Indian J Pathol Microbiol [serial online] 2010 [cited 2023 May 30];53:195-7. Available from:


Neuroendocrine Tumor (NET) is known to frequently occur in the gastrointestinal tract, arising from Kultschitsky cells. Primary NET of kidney is extremely rare. To date, approximately 40 cases of primary renal NET have been reported. Resnick [1] reported the first case of primary renal carcinoid and out of these 40 cases, 11 have been reported in horseshoe kidney (HSK). [2] The origin of renal NET is controversial because enterochromaffin cells are not found in normal renal parenchyma. They could originate from neuroendocrine cells associated with intestinal metaplasia of the renal collecting system or neuroendocrine cells found within teratomatous intestinal or respiratory epithelium within kidney. This explains the more frequent association of NET with HSK because of more common presence of abnormalities or teratomatous elements in these kidneys. Renal NET is the second most common prevalent genitourinary NET in each sex, following testicular NET in men and ovarian NET in women. Significant adverse prognostic factors include: age greater than 40 years, tumor greater than 4 cm, purely solid tumors on cut surface, mitotic rate higher than 1/10 high power field, metastasis at initial diagnosis and tumors extending throughout renal capsule. [3] Primary NETs of kidney include carcinoid tumor, large cell neuroendocrine carcinoma (LCNEC) and small cell carcinoma (SCC). Renal carcinoids have a variable clinical course; SCC and LCNEC are associated with poor clinical outcomes. [4] We report another case of primary NET in HSK, in a 35-year-old man.

A 35-year-old male presented with complaints of continuous dull, aching right flank pain of one year duration, associated with pain over scrotal region. The patient had hematuria associated with passage of clots,of one year duration, occurring at intervals of about 15 days. He also had off and on dull aching left flank pain of one year duration with occasional attacks of pain in left testis and past medical history of left open ureterolithotomy 15 years back. Examination revealed palpable lump over umbilical region extending to right lumbar area about 8cm/4cm size, non tender, hard in consistency, with not so well-defined margins. Basic hematological and biochemical parameters were within normal limits, blood urea-27 mg%, serum creatinine-1.1mg%. Routine urine examination revealed protein +, 30-50 red blood cells (RBCs)/high power field (HPF) and 1-3 white blood cells (WBCs)/HPF. Ultrasonogram (USG) of abdomen showed small right renal calculus with mild right hydronephrosis, with retroperitoneal mass in midline. Abdominal contrast enhanced computerized tomogram (CECT) revealed hypodense mass lesion with dense calcification affecting isthmus of HSK and lower half right renal pelvis leading to pelvicalyceal system (PCS) dilatation and delayed nephrogram.

Both renal veins and inferior venacava (IVC) were normal with no lymphadenopathy [Figure 1]. Right nephrectomy with isthmusectomy was performed. Tumor was found involving isthmus of HSK extending to lower pole of right kidney about 9cm/7cm size [Figure 2]. There were three renal arteries and two right renal veins [Figure 3]. There was a tumor extension into inferior calyx left kidney which was removed. Histopathological examination revealed tumor cells arranged in glandular and focal trabecular pattern. The cells were round with eosinophilic cytoplasm [Figure 4]. Nuclei were round to oval with salt pepper chromatin and minimal pleomorphism. Mitotic activity varied from 3-5/10high power field. Capsular and vascular invasion was not seen. Resected ends of ureter and hilar vessels free of tumor. MIB-1 labelling index was 4-5%. Immunohistochemically, cells were positive for cytokeratin (CK), neuron specific enolase (NSE), chromogranin and synaptophysin [Figure 5].

NET associated with HSK present a better prognosis than those occurring in normal kidneys, even over long term follow-up periods. While renal NETs can follow an aggressive clinical course, those arising within HSK appear to be more benign. Outcome appears not to be directly related to presence of nodal metastases or type of surgery. Development of distant metastasis after surgery seems not to worsen prognosis. [5] Neuroendocrine tumors on immunostaining show positivity for synaptophysin, neuron specific enolase and vimentin. The use of chemotherapy as adjuvant or palliation has been unsuccessful and radiotherapy is only palliative. Hence, for localized tumors, an aggressive surgical approach should be the treatment of choice. A similar pattern of aggressive surgical management was followed in our case. Histopathology revealed resected margins being free of tumor with no capsular invasion. Our patient had a proliferative index of 5, which suggests tumor to be malignant. Patient had a normal postoperative outcome. Postoperative parameters were within normal limits - blood urea - 30mg% and serum creatinine - 1.2 mg%. In view of no positive margins and no lymphadenopathy, patient was not given any chemoradiation postoperatively. Patient did not report with any postoperative complications. Thus neuroendocrine tumors in horseshoe kidneys warrant aggressive surgical treatment for a normal postoperative outcome. Such patients usually do not need postoperative chemoradiation if whole tumor has been removed and no lymphadenopathy or metastasis has been documented.

Early diagnosis and aggressive surgical treatment are imperative for a normal postoperative outcome in neuroendocrine tumors. Chemoradiation has been found to have little beneficial effect in such tumors.

   References Top

1.Resnick ME, Unterberger H, McLoughlin PT. Renal carcinoid producing the carcinoid syndrome. Med Times 1966;94:895-6.  Back to cited text no. 1  [PUBMED]  [FULLTEXT]  
2.Rodriguez-Covarribias F, Gomez X, Valerio JC, Lome-Maldonado C, Gabilondo F. Carcinoid tumour arising in a horseshoe kidney. Int Urol Nephrol 2007;39:373-6.  Back to cited text no. 2      
3.Romero Fr, Rais-Bahrami S, Permpongkosol S, Fine SW, Kohanim S, Jarrett TW. Primary carcinoid tumors of the kidney. J Urol 2006;176:2359-6.  Back to cited text no. 3  [PUBMED]  [FULLTEXT]  
4.Lane BR, Chery F, Jow G, Sercia L, Magi-Galluzzi C, Novick AC, Zhou M. Renal neuroendocrine tumours: a clinocopathologic study. BJU Int 2007;100:1030-5.  Back to cited text no. 4      
5.Kulke MH, Mayer RJ. Carcinoid tumors. N Engl J Med 1999;340:858-8.  Back to cited text no. 5  [PUBMED]  [FULLTEXT]  

Correspondence Address:
Ajay Anand
Department of Urology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0377-4929.59239

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  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]

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