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Korean J Urol Oncol 2010;8(2):71-74

Carcinoid Tumor of the

Yun Seok Jung, Jun Sung Koh, Su Lim Lee1, Chang Hee Han, Sung Hak Kang, Eun Jung Lee2, Yong Seok Lee Departments of Urology, 1Radiology and 2Pathology, College of Medicine, The Catholic University of Korea, Seoul, Korea

Carcinoid tumors are low-grade malignant tumors with neuroendocrine differentiation, usually located in the gastrointestinal and respiratory tracts. Primary renal carcinoid tumors are extremely uncommon and there are less than seventy cases documented in the literature. Little is known about its usual presentation, pathophysiology, and prognosis. We report a case of primary renal carcinoid tumor in a 49-year old man, diagnosed via a hand-assisted laparoscopic radical . Pathologic findings of the tumor, clinical manifestation, and treatment are discussed. (Korean J Urol Oncol 2010;8:71-74) 󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏󰠏 Key Words: Carcinoid tumor, Kidney

Carcinoid tumor is made up of neuroendocrine cells with the physical exam, e.g. palpable mass or flank tenderness. Vital low-grade malignant potential. Although it is common in the signs were all within normal limits and the results of a com- gastrointestinal and respiratory organs, it is rarely found in the plete blood count, routine chemistry tests, urine analysis, and urogenital system.1 Neuroendocrine cells are occasionally found urine culture were within the normal range. The patient had no in the bladder and the prostate, but carcinoid tumor in the retro- clinical manifestations of such as is extremely rare. Hence, its clinical and histo- or . An abdominal computed tomography (CT) scan logical behavior, and the remain largely unknown.2 was performed, and it demonstrated an enhancing , ap- We report a case of primary renal carcinoid tumor in an asymp- proximately 3.5x3.1cm in size, in the left and re- tomatic male, found to have a renal mass during a routine med- nal . It accompanied peripheral calcification and com- ical examination. Histological analysis on the specimen from pression of the renal pelvis and calyx, resulting in hydro- a hand-assisted laparoscopic radical nephrectomy confirmed the nephrosis (Fig. 1). We suspected that a papillary-type, endo- diagnosis. phytic renal cell was more likely, as opposed to a transitional cell carcinoma. This was based on the demonstrated CASE REPORT morphology, e.g. the location of the epicenter in the renal me- dulla, the surrounding calcification, and the lesion compressing A 49-year old man was incidentally found to have a left renal the left renal pelvis rather than infiltrating it. mass upon abdominal ultrasonography during a comprehensive We performed a hand-assisted, laparoscopic radical nephrec- medical examination. He has no significant past medical or tomy. A partial nephrectomy with a complete resection of the smoking history. There were no specific abnormal findings in tumor would have been ideal, but it was not attempted because the mass was near the renal pedicle, positioned at the mid-pole Received March 22, 2010, Accepted May 31, 2010 of the kidney. We did not note any enlargement of the lymph Corresponding Author: Yong Seok Lee, Department of Urology, nodes or severe adhesion during the operation. In gross exami- Uijongbu St. Mary’s Hospital, The Catholic University of nation, the tumor was well-circumscribed, and yet fragile. It Korea College of Medicine, 65-1, Keumoh-dong, Uijongbu 480-717, Korea. Tel: 82-31-820-3588, Fax: 82-31-847-6133, measured 4.0cm at the maximum diameter, and was indeed E-mail: [email protected] confined to the mid-pole. The bisected surface of the tumor was 71 72 대한비뇨기종양학회지：제8권 제2호 2010

Fig. 1. The abdominal CT scan shows the left renal enhancing Fig. 3. The shows diffuse cytoplasmic ball-type endophytic mass in the medulla and renal pelvis with strong staining for in the tumor cells. calcification resulting in hydronephrosis.

Fig. 4. Upon electron microscopy, the tumor cell contained many membrane-bounded dense core granules filling the of the cells (x20,000) Fig. 2. Miscoscopically, the tumor cells were rounded to oval with finely dispersed nuclear chromatin and prominent nucleoli, and they were arranged in a tightly packed trabecular pattern of renchyma and microscopic vascular invasion was present. monotonous uniform cells, which is typical for carcinoid tumor Osseous metaplasia was also observed. Neither a precursor le- (H&E, x200). sion of , nor intestinal metaplasia was observed. Immnostaining for the NE marker, synaptophysin, yellow-tan in color with foci of hemorrhage. No abnormalities was strongly positive (Fig. 3), although immnostaining for chro- were observed in the rest of the urogenital tract. mogranin and CD56 were negative. Upon electron microscopy, Microscopically, the tumor had a trabecular or ribbon-like ar- the neoplastic cells contained dense core granules in the cyto- rangement, admixed with solid nests within highly vascularized plasm (Fig. 4). stroma. The tumor cells were large and round to oval in shape. The patient tolerated the procedure well and had an un- They had abundant acidophilic cytoplasm. The nuclei were also remarkable postoperative recovery course. He was discharged round to oval in shape, uniformly or minimally pleomorphic, home on the fifth postoperative day. and had evenly-dispersed, coarse, granular chromatin and prom- inent nucleoli (Fig. 2). The number of mitotic figures was low DISCUSSION at 0-1/10 high power fields (HPFs) and no abnormal mitoses were observed. The tumor had focally invaded the kidney pa- Primary carcinoid tumors of the kidney are very rare. The Yun Seok Jung, et al：Renal Carcinoid Tumor 73 first case was reported in 1966 by Resnick et al.,3 followed by markers of neuroendocrine tissue and include neuron-specific 64 cases documented in the literature. Renal carcinoid tumor enolase, synaptophysin and chromogranin. In our case, the tu- is thought to arise from pre-existing of neuro- mor tissue sections were stained positive for synaptophysin. endocrine cells, which are often found in teratomatous or meta- We believe that our case represents primary renal carcinoid plastic . Because neuroendocrine cells are not present tumor. It fulfills both histologic and immunohistochemical in normal kidneys, another possible explanation for its patho- criteria. The likelihood of carcinoid tumor metastasizing to the genesis can come from misplaced neural crest cells during kidney is generally considered low, and it is even lower in our embryogenesis.1 Over 80% of carcinoid tumors develop in the case because the patient had no gastrointestinal complaints, nor wall of the hollow organs of the and an any of the symptoms of carcinoid syndrome. There were no additional 10% are seen in the as either carcinoid ad- findings on the CT scans and x-ray films of the thorax, and enomas or malignant carcinoid tumors.2 Its presences in other likewise, no gross abnormalities were observed intraoperatively. locations, e.g. the , , breast, ovary, uterus, testis, Complete surgical resection in the form of a total or partial urethra, prostate and kidney, have been rarely reported. In nephrectomy is the primary treatment for renal carcinoid, and Korea, cases have been reported of primary renal carcinoid tu- this is curative for localized disease.8 mors, as well as carcinoid tumors in horseshoe kidneys and the In our review of the literature, 47% of the patients who un- bladder.4-6 The appropriate management is not well established, derwent nephrectomy for renal carcinoid were disease-free after owing to the rarity and the lack of understanding on its clinical a mean follow-up of 43 months.2 The 5-year survival rates for course. Some authors have reported that renal carcinoid tumors patients with carcinoid tumors are 65% for localized, and 36% occur predominantly in relatively younger adults, i.e. 35.7% of for metastatic tumor.9 Shurtleff et al.1 reported that the prog- the patients were 40 years in age or younger, and there is no nosis for primary renal carcinoid tumor is relatively better. predilection for gender. On the other hand, primary carcinoid Among their reviewed cases, 23% of the patients developed tumors in horseshoe kidneys have been more common in men , and the most common sites of metastasis were the with a male-to-female ratio of 1.5:1.2 The most common symp- lymph nodes and liver. The patients who had metastasis and toms include abdominal or flank pain, followed by , still survived had a mean follow-up of 26.6 months (range: 7-40 constipation, , weight loss and testicular pain. Fewer pa- months). This demonstrates that these patients might survive for tients present with constitutional symptoms, and others are en- many months, even if they have metastasis. tirely until incidental detection of the tumor. Romero et al.2 proposed that the significant adverse prognostic Carcinoid syndrome occurs in only 3 percent of the patients factors of renal carcinoid tumors include 1) age greater than with carcinoid tumors, and is almost always associated with liv- 40 years, 2) tumor size greater than 4cm, 3) purely solid tumors er metastasis. Nevertheless, when carcinoid tumor has direct ac- on the cut surface, 4) mitotic rate higher than 1/10 HPF, 5) cess to the systemic circulation, the syndrome can occur in the metastasis at the initial diagnosis, and 6) tumor extending absence of liver involvement.7 In our case, the patient had no throughout the renal capsule. clinical manifestations of carcinoid syndrome, such as flushing, The widespread use of imaging has led to increased detection generalized edema, diarrhea, nausea, vomiting or dyspnea. His of carcinoid tumors of the kidney during the recent years. The liver function test was also within normal limits. There is no frequency of follow-up imaging studies, including CT, depends specific finding on CT or magnetic resonance imaging (MRI) on the patient’s condition and the adverse prognostic factors. that can solely differentiate renal carcinoid tumor from the oth- The fact that there is a paucity of reports of primary renal er types of renal tumors without exam. However, the carcionoids in the literature means we do not have a strong con- most common radiological feature of all carcinoid tumors is the sensus on the management. Currently, the main approach is sur- accompanying calcification, which has been seen in 26.5% of gical and almost all the reported cases are managed by com- the reported cases of primary renal carcinoid tumor.2 In our plete resection of the tumor. However, we do not know if an case, we found calcification on CT and osseous metaplasia on expectant management with frequent follow-up exams is just the pathology exam. The final diagnosis can be made histologi- as safe and effective for asymptomatic carcioniods without cally by a positive reaction to silver stains, which are specific metastasis. Because our patient was absolutely asymptomatic 74 대한비뇨기종양학회지：제8권 제2호 2010 and it is possible that he could remain so during his entire 2. Romero FR, Rais-Bahrami S, Permpongkosol S, Fine SW, life-span, it is difficult to state that the benefits of the surgical Kohanim S, Jarrett TW. Prinary carcinoid tumors of the kidney. J Urol 2006;176:2359-66 resection clearly outweighed its risks, e.g. complications of an- 3. Resnick ME, Unterberger H, McLoughlin PT. Renal carcinoid esthesia, postoperative infection or morbidity, risk of deep vein producing the carcinoid syndrome. Med Times 1966;94:895-6 thrombosis, etc. As there are more reports of renal 4. Son EH, Joung YT, Lee CK, Rhew HY. Carcinoid tumor in available, and as our understanding of its epidemiology, patho- . Korean J Urol 1998;39:811-4 physiology, pattern of spread, and prognosis with metastatic po- 5. Seo HP, Shin DE, Lim DH, Muhn HY, Kim CS. Primary renal tentials, we would be able to offer a better advice to another carcinoid tumor. Korean J Urol 2009;50:293-5 6. Im PB, Lee DH, Suh HJ, Lee JH, Choi AR, Kim KM, et al. 47-year old asymptomatic patient with a primary renal A case of primary carcinoid tumor of the urinary bladder. carcinoid. Korean J Urol 2001;42:671-4 7. Rougier P, Mitry E. in the treatment of neuro- endocrine malignant tumors. Digestion 2000;62(Suppl 1):73-8 REFERENCES 8. Lane BR, Chery F, Jour G, Sercia L, Magi-Galluzzi C, Novick AC, et al. Renal neuroendocrine tumours: a clinicopathological 1. Shurtleff BT, Shvarts O, Rajfer J. Carcinoid tumor of the kid- study. BJU Int 2007;100:1030-5 ney: case report and review of the literature. Rev Urol 9. Kulke MH, Mayer RJ. Carcinoid tumors. N Engl J Med 2005;7:229-33 1999;340:858-68