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CASE REPORT Table of Contents   
Year : 2010  |  Volume : 53  |  Issue : 4  |  Page : 772-774
Primary carcinoid tumor of the kidney: Case report and brief review of literature

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

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Date of Web Publication27-Oct-2010


Primary carcinoid tumor of the kidney is an extremely uncommon tumor. As a consequence, very little is known about its histogenesis, clinicopathologic features and prognosis. We herein describe a case of renal carcinoid with atypical features.

Keywords: Atypical carcinoid, carcinoid tumor, kidney, neuroendocrine carcinoma, renal tumors

How to cite this article:
Jain D, Sharma MC, Singh K, Gupta NP. Primary carcinoid tumor of the kidney: Case report and brief review of literature. Indian J Pathol Microbiol 2010;53:772-4

How to cite this URL:
Jain D, Sharma MC, Singh K, Gupta NP. Primary carcinoid tumor of the kidney: Case report and brief review of literature. Indian J Pathol Microbiol [serial online] 2010 [cited 2021 Aug 5];53:772-4. Available from: https://www.ijpmonline.org/text.asp?2010/53/4/772/72087

   Introduction Top

Renal carcinoid tumors are rare. The clinicopathologic features are not well characterized and histogenesis remains deba table. There was no uniform classification system for these tumors in the past but in the 2004, WHO Classification scheme regarded these as distinct entities with histological features similar to carcinoid tumors at other locations. [1] Herein, we report a case of primary carcinoid tumor of the kidney with unusual features.

   Case Report Top

Clinical Summary

A 40-year-old woman presented with an episode of colicky pain in the left loin region, which was non-radiating. There was no history of hematuria, urinary urgency, frequency or burning micturition. No history of flushing or diarrhea could be demonstrated. Family and personal history were non-contributory and she was a non-smoker. She was investigated to rule out renal calculi. Routine blood examination and serum chemistry revealed no abnormality. Physical examination showed a vague bimanually palpable mass in the left kidney. Ultrasonography showed a mass in the mid-polar region of the left kidney, which was hypervascular on angiography. Magnetic resonance imaging (MRI) showed approximately 3 × 2.5 × 1 cm mass, which was located in the hilar region. No infiltration into the renal vessels or inferior vena cava was detected. Metastatic work-up revealed no other lesion in the chest and liver. Bone scan did not show any metastatic focus. Left radical nephrectomy was done.

Gross Features

On gross examination, a solid tumor of 3.5 cm diameter was seen arising from the renal parenchyma in the hilar region and was impinging on the pelvicalyceal system medially which was otherwise unremarkable. The cut surface of the tumor was firm and whitish with areas of hemorrhage. The tumor was un-encapsulated and relatively well circumscribed. Rest of the kidney was unremarkable.

Microscopic Findings

Microscopically, the tumor was composed of anastomosing cords, trabeculae and solid nests of low columnar cells separated by a vascular stroma [Figure 1]a and b. These cells possessed centrally placed oval nuclei with inconspicuous nucleoli, and eosinophilic finely granular cytoplasm. At places, cells were arranged in solid pattern [Figure 1]c. There was peripheral palisading of the cells with salt-and-pepper chromatin pattern. Focal aggregates of lymphoid cells as well as sprinkling of lymphocytes was also seen [Figure 1]c and d. Mitotic rate was 1 per 10 high power fields (hpf). Areas of tumor necrosis were also identified. The tumor was infiltrating into the hilar adipose tissue and showed marked desmoplasia [Figure 1]e. Multiple foci of perineural, lymphatic and vascular invasion were seen [Figure 1]f-h. No intra or extra-cellular mucin was identified. Immunohistochemical staining revealed diffuse and intense staining for pan-cytokeratin, synaptophysin, chromogranin A and NSE, however tumor cells were negative for vimentin, EMA and S-100 protein [Figure 2]a-c.
Figure 1: (a-d): Photomicrographs showing tumor cells arranged in trabecular and solid pattern (a, H and E, ×400; b and c, H and E, ×200), lymphocytic sprinkling (c) and lymphoid aggregate formation (d, H and E, ×200)
(e-h): Photomicrographs showing a tumor with marked desmoplasia (e, H and E; ×100), perineural invasion (f, H and E; ×200), lymphatic invasion (arrow), (g, H and E; ×100) and vascular invasion (h, H and E; ×200)

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Figure 2 (a-d): Tumor cells are immunopositive for chromogranin, synaptophysin and neuron-specific enolase (a-c IHC; ×200 each); Electron photomicrograph showing electron dense granules of variable sizes (original magnification; d ×8200)

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Ultrastructural examination revealed numerous electron dense, membrane-bound round granules of variable diameter in the cytoplasm [Figure 2]d. A narrow peripheral lighter zone was present in some of the granules. Based on the above features; the diagnosis of carcinoid was entertained.

The patient is asymptomatic and disease-free until last follow-up at five years after surgery.

   Discussion Top

Carcinoid tumors are found most commonly in the gastrointestinal tract and respiratory system but are rare in the genitourinary system. [2] Primary renal carcinoids are extremely rare. Murali et al.[2] reviewed the literature till 2006 and found 51 cases reported in the literature. We reviewed the literature published after that and found 39 more cases reported, thus amounting to 90 cases reported to date. [3],[4] Of these 90 patients, in seven patients (7.07%) carcinoid tumor was a part of a teratoma. [3] There is no gender predilection and age ranged from 23 to 78 years, but the mean age of occurrence is lower than renal cell carcinoma. Most of the renal carcinoids are asymptomatic. In the symptomatic patients, abdominal masses and acute loin pain are the most common symptoms [4] as observed in the patient under discussion. This was probably secondary to hemorrhage in the tumor. Due to some unknown reasons, the patients with horseshoe kidney are more prone to have carcinoid tumor. [2]

Renal carcinoid tumor shows characteristic features of carcinoid tumors seen elsewhere. The latest WHO classification proposed classification similar to the carcinoid tumors of other places. [1] The majority of the renal carcinoids reported in the literature are typical carcinoid with low mitotic activity and absence of necrosis. The mitotic activity of more than two and presence of necrosis are features of an atypical carcinoid. [1] The case under discussion had mitotic rate of 1/10 hpf but showed perineural, lymphatic, vascular invasion and necrosis. Histological features were borderline between a benign and atypical carcinoid tumor. The atypical carcinoid of the kidney is rare. [5] In a large series reported by Hansel et al.,[6] only one case was of atypical carcinoid. The mitotic activity in that tumor was 4 per 10 hpf and this patient died within 8 months. Quinchon et al.[5] reported a case, which had two mitoses per 10 hpfs with large necrotic and hemorrhagic areas. Some tumor nests invaded the perinephric fat and metastasis in the regional lymph nodes was found. The authors made the diagnosis of primary atypical renal carcinoid. On follow-up, vertebral and hepatic metastases occurred 10 years after the initial diagnosis. Although we observed some atypical features in the form of mitotic activity, areas of necrosis, perineural and vascular invasion in the case under discussion, she is however doing well and revealed no recurrence or metastasis in the follow-up after 5 years of the diagnosis; though long follow-up is required to predict the exact behavior of this tumor. Although the primary renal neuroendocrine tumors are rare, there is a need to classify them like gastrointestinal and lung neuroendocrine tumors into benign, borderline and malignant lesions in order to attain their clinical relevance and prognostic significance. Quinchon et al.[5] have emphasized this need in their description of primary atypical carcinoid tumor of the kidney. Owing to the rarity of these lesions and short follow-up of the cases published in the literature, the prognosis and clinical behavior of these tumors remain unclear. The surgery is the treatment of choice and even partial nephrectomy is recommended for smaller tumors. The chemotherapy is recommended for atypical cases, however is not of much use.

   References Top

1.Eble JN, Sauter G, Epstein JL. World Health Organization Classification of tumours. Pathology and genetics of tumours of the urinary system and male genital organs. volume 7. Third Edition Lyon, France: IARC Press; 2004. p. 81-2.  Back to cited text no. 1
2.Murali R, Kneale K, Lalak N, Delprado W. Carcinoid tumors of the urinary tract and prostate. Arch Pathol Lab Med 2006;130:1693-706.   Back to cited text no. 2
3.Armah HB, Parwani AV. Primary carcinoid tumor arising within mature teratoma of the kidney: Report of a rare entity and review of the literature. Diagn Pathol 2007;2:15.   Back to cited text no. 3
4.Chung HY, Lau WH, Chu SM, Collins RJ, Tam PC. Carcinoid tumour of the kidney in a Chinese woman presenting with loin pain. Hong Kong Med J 2007;13:406-8.  Back to cited text no. 4
5.Quinchon JF, Aubert S, Biserte J, Lemaitre L, Gosselin B, Leroy X. Primary atypical carcinoid of the kidney: A classification is needed. Pathology 2003;35:353-5.  Back to cited text no. 5
6.Hansel DE, Epstein JI, Berbescu E, Fine SW, Young RH, Cheville JC. Renal carcinoid tumor: A clinicopathologic study of 21 cases. Am J Surg Pathol 2007;31:1539-44.  Back to cited text no. 6

Correspondence Address:
Mehar Chand Sharma
Department of Pathology, All India Institute of Medical Sciences, New Delhi - 110029
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0377-4929.72087

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