Primary carcinoid of the kidney

Primary Carcinoid Tumor of the Renal Pelvis Arising From Intestinal Metaplasia: An Unusual Histogenetic Pathway?

OBJECTIVES

Primary carcinoid tumor of the renal pelvis is a rare neoplasm with few cases reported in the literature. Here we present the clinical and histopathologic findings of a primary carcinoid tumor arising in the left renal pelvis of a horseshoe kidney in a 61-year-old female patient.

MATERIALS AND METHODS

Pathologic features were evaluated with standard hematoxylin and eosin sections and immunohistochemical studies. A literature review was performed to place our case in context to previous reports.

RESULTS

The tumor was associated with intestinal metaplasia with high-grade dysplasia and neuroendocrine hyperplasia. Molecular testing for microsatellite instability and loss of heterozygosity were negative.

CONCLUSIONS

This report portrays a unique presentation of carcinoid tumor arising from intestinal metaplasia of the pelvic urothelium, and supports its histogenesis from urothelial intestinal metaplasia and neuroendocrine hyperplasia.

Primary renal carcinoid: treatment and prognosis

Primary carcinoid tumors of the kidney are very rare, malignant tumors consisting of neuroendocrine cells. The pathogenesis of renal carcinoid is unclear because neuroendocrine cells are not normally found in adult renal parenchyma. Electron microscopy, immunohistochemistry, octreotide scan, positron emission tomography along with conventional radiographic imaging techniques are used in diagnosis and follow-up. Presenting symptoms usually include flank pain and haematuria. Early stage disease is treated with surgery only. However, randomized trials are lacking because of the very low number of reported cases. Thus, the role of debulking surgery, chemotherapy, radiotherapy, octreotide and targeted therapy in the management of advanced disease remains an open question. In this article the clinicopathologic features and prognosis of this very rare disease along with treatment outcomes of the reported cases are reviewed. In addition, we report a new case of a metastatic primary renal atypical carcinoid tumor treated with octreotide therapy.

Renal neuroendocrine tumors

Objectives:

Neuroendocrine tumors (NETs) are uncommon tumors that exhibit a wide range of neuroendocrine differentiation and biological behavior. Primary NETs of the kidney, including carcinoid tumor, small cell carcinoma (SCC), and large cell neuroendocrine carcinoma (LCNEC) are exceedingly rare.

Materials and Methods:

The clinicopathologic features of renal NETs diagnosed at a single institution were reviewed along with all reported cases in the worldwide literature.

Results:

Eighty renal NETs have been described, including nine from our institution. Differentiation between renal NETs and the more common renal neoplasms (renal cell carcinoma, transitional cell carcinoma) can be difficult since clinical, radiographic, and histopathologic features overlap. Immunohistochemical staining for neuroendocrine markers, such as synaptophysin and chromogranin, can be particularly helpful in this regard. Renal carcinoids are typically slow-growing, may secrete hormones, and pursue a variable clinical course. In contrast, SCC and LCNEC often present with locally advanced or metastatic disease and carry a poor prognosis. Nephrectomy can be curative for clinically localized NETs, but multimodality treatment is indicated for advanced disease.

Conclusions:

A spectrum of NETs can rarely occur in the kidney. Renal carcinoids have a variable clinical course; SCC and LCNEC are associated with poor clinical outcomes. Diagnosis of NETs, especially LCNEC, requires awareness of their rare occurrence and prudent use of immunohistochemical neuroendocrine markers.

Large-cell neuroendocrine carcinoma of the kidney: Clinicopathologic features

Neuroendocrine tumors are rare entities which can arise in various sites of the body. The presence of both neural and endocrine elements in conjunction characterises these tumors pathologically. Most of these tumors are non secretory in nature, and arise in organs where there may not be any neuroendocrine elements. Carcinoid tumors are the most common entities reported in the kidney. There have been only a couple of case series of non-carcinoid neuroendocrine tumors of the kidney reported in literature. Surgical resection appears to be the best available treatment modality. Chemotherapy has been attempted with dismal results. The biological behaviour is determined by the occurrence of metastases to the liver or lung. We report a patient with a large cell neuroendocrine carcinoma of the kidney, who underwent radical resection and is doing well on follow-up. The diagnosis was confirmed by immune-histochemistry.

Renal carcinoid tumor: a clinicopathologic study of 21 cases

Renal carcinoid tumors are exceedingly rare tumors that have been primarily documented as case reports in the literature. In this study, we report a series of 21 renal carcinoid tumors, with emphasis on histopathologic features and clinical outcomes. Patient age ranged from 27 to 78 years (average 52 y). The majority of specimens consisted of radical nephrectomies with or without associated lymph node dissection. Nine tumors were present in the left kidney and 10 were present in the right; location was not available for 2 specimens. No anatomic region of the kidney appeared to be preferentially involved. Twenty tumors were unifocal and ranged in size from 2.6 to 17 cm (average 6.4 cm), and 1 tumor presented as 2 nodules measuring 1 and 2.8 cm. Four patients had a documented history of a horseshoe kidney. Two patients had a history of renal calculi and 1 patient had a history of urothelial carcinoma 8 years prior. Presenting symptoms and clinical findings included back or flank pain (n=6/9), enlarging abdominal mass or fullness (n=2/9), hematuria (n=2/9), and anemia (n=1/9). Twelve patients had concurrent metastases at the time of initial surgery to sites including lymph nodes (n=11/12), liver (n=5/12), bone (n=1/12), and lung (n=1/12). One additional patient developed subsequent metastases to the liver within 6 months of surgery. Examination of the specimens identified carcinoid tumor with a variety of patterns including tightly packed cords and trabeculae with minimal stroma (n=17/21), trabecular growth with prominent stroma (n=4/21), focal solid nests (n=4/21), focal glandlike lumina (n=4/21). The border between tumor and normal kidney was sharply defined in most cases (n=16/21), although focal infiltration was noted in 5/21 cases. Extracapsular extension was documented in 11/21 (52%) cases. Calcifications were present in 5/21 cases. Mitotic activity, measured as mitoses per 10 high-power fields, ranged from 0 to 2 in most cases, with 1 case demonstrating up to 4 mitotic figures per single high-power field. Necrosis was absent in all cases. Immunostains were frequently positive for synaptophysin (n=18/20), chromogranin (n=13/20), Cam5.2 (n=14/16), and vimentin (n=12/15). CK7 was focally positive in a small subset of cases (n=3/18) and CK20 was positive in 1 case. TTF-1 and WT-1 were negative in all cases examined. Clinical follow-up was available on 15 patients and ranged from 3 months to 11 years. One patient died of disease at 8 months after surgery and 1 patient died without disease at 11 years after surgery. Of the remaining patients, 7 patients were alive without disease and 6 patients were alive with disease. Additional metastases developed in 4 patients and included metastases to the liver and bone.

Renal neuroendocrine tumours: a clinicopathological study

OBJECTIVES

To report cases of primary neuroendocrine tumours (NETs) of the kidney, including carcinoid tumour, large cell neuroendocrine carcinoma (LCNEC) and small cell carcinoma (SCC), which show a wide range of NE differentiation and biological behaviour, and are exceedingly rare.

PATIENTS AND METHODS

The clinicopathological features of all nine renal NETs diagnosed during a 7-year period were reviewed.

RESULTS

Six carcinoids, two SCC and one LCNEC were identified from 2780 kidney tumours. No patient had carcinoid syndrome or other NE symptoms. Three of six carcinoids and no SCC/LCNEC arose in horseshoe kidneys. The mean size of the six carcinoids and three SCC/LCNEC was 4.8 cm and 12.2 cm, respectively. No carcinoid had tumour necrosis or mitosis. By contrast, three SCC/LCNEC had extensive tumour necrosis and brisk mitosis. All renal NETs were positive for synaptophysin but were variably positive for chromogranin and CD56. Three of six carcinoid tumours were confined to the kidney, and four of five patients were disease-free at a mean (range) of 26 (6-74) months. One patient with nodal metastases has had no recurrence and another died with liver metastases. Three patients with SCC/LCNEC each presented with locally advanced disease and extensive lymphadenopathy; two of them died from distant metastasis or local tumour progression, and the third is currently alive with disease.

CONCLUSIONS

Various NETs can occur in the kidney, but rarely. Renal carcinoids have a variable clinical course; SCC and LCNEC are associated with poor clinical outcomes. The diagnosis of NETs, especially LCNEC, requires awareness of their rare occurrence and prudent use of immunohistochemical NE markers.

Primary Carcinoid Tumors of the Kidney

PURPOSE

We describe in detail the features of carcinoid tumors of the kidney. We evaluated possible prognostic factors.

MATERIALS AND METHODS

An extensive search was performed in the medical literature regarding primary carcinoid tumors of the kidney. Epidemiological, clinical, diagnostic, histopathological, therapeutic and prognostic data were evaluated. Several potential risk factors were compared with the incidence of metastases and clinical outcome of the patients.

RESULTS

A total of 56 case reports were reviewed. Median patient age was 49 years. Horseshoe kidneys were present in 17.8% of cases. Incidental diagnosis was made in 28.6% of patients. The most common symptom was abdominal or flank pain and neuroendocrine syndromes occurred with only 12.7% of primary renal carcinoid tumors. Of the patients 73.6% presented with tumors larger than 4 cm. Metastases were present in 45.6% of patients at initial diagnosis and almost 60% with tumors greater than 4 cm had metastases.

CONCLUSIONS

Renal carcinoid is the second most prevalent genitourinary carcinoid in each sex, following testicular carcinoids in men and ovarian tumors in women. Significant adverse prognostic factors include age greater than 40 years, tumor size greater than 4 cm, purely solid tumors on the cut surface, mitotic rate higher than 1/10 high power fields, metastasis at initial diagnosis and tumors extending throughout the renal capsule.

Carcinoid tumors of the urinary tract and prostate

CONTEXT

Carcinoid tumors are exceedingly rare in the genitourinary tract and may occur in the kidney, urinary bladder, urethra, or prostate.

OBJECTIVE

To review the clinical and pathologic features of carcinoid tumors occurring in the urinary tract and prostate.

DATA SOURCES

We searched the English language literature using MEDLINE and Ovid.

CONCLUSIONS

Carcinoid tumors of the urinary tract and prostate share similar morphologic features with their counterparts in other organs. The differential diagnosis includes metastatic carcinoid tumor, paraganglioma, and nested variants of urothelial and prostatic carcinomas. Correlation of the clinical presentation and histopathologic features (including the immunohistochemical profile) will ensure accurate diagnosis of these rare tumors.

Primary carcinoid tumor in a polycystic kidney

A case of a primary carcinoid tumor within a polycystic kidney is reported. A 51-year-old woman with autosomal dominant polycystic kidney disease (ADPKD) underwent a bilateral nephrectomy because of an infection in her polycystic kidneys. A tumor (1.5 cm in diameter) was incidentally found close to the hilum of the left kidney. Histologically, the tumor exhibited a predominantly trabecular pattern of cuboidal or columnar cells. Grimelius staining showed numerous silver-stained neurosecretory granules in most of the tumor cells; the tumor cells were also positive for chromogranin, synaptophysin, prostatic acid phosphatase (PAP) and neuron-specific enolase (NSE). The tumor was diagnosed as a primary carcinoid tumor of the kidney. Primary renal carcinoid is a very rare neoplasm, and this is the first report of such a lesion arising in a polycystic kidney.

Primary carcinoid tumor arising in a mature teratoma of the kidney: a case report and review of the literature

Primary carcinoid tumor, especially that arising in a mature teratoma of the kidney, is extremely rare; only 3 cases have been reported in the world literature to date. Because of the rarity of the lesion, its histogenesis and prognosis are unknown. We report a case of primary renal carcinoid tumor occurring in a mature teratoma in a 30-year-old woman. A computed tomographic scan of the abdomen revealed a mass in the left kidney containing dense calcification with minimal contrast enhancement. Histologically, the tumor was composed of trabecular and anastomosing ribbonlike nests, identical to the features of carcinoid tumors of other sites. Immunohistochemical stainings were positive for cytokeratin, neuron-specific enolase, and chromogranin. In addition, there were mature teratoid tissues, such as columnar epithelium, smooth muscle, and bone. The carcinoid tumor was under and closely apposed to the lining of the cysts. The patient did not have clinical manifestations of the carcinoid syndrome and had an uneventful recovery.

Searching for an intrinsic neuroendocrine cell in the kidney. An immunohistochemical study of the fetal, infantile and adult kidney

The pathogenesis of primary renal carcinoid tumor is unknown. One hypothesis has implied derivation from a yet unrecognized intrinsic neuroendocrine cell in the renal parenchyma/hilum either as a minute endocrineparacrine constituent or resulting from entrapped/misplaced progenitor cells of the so-called dispersed neuroendocrine system during organogenesis. Immunohistochemical staining for chromogranin and serotonin was systematically performed on a whole-mount and geographically mapped normal adult kidney, kidneys from 15 fetuses (age range: 15 to 38 weeks), and renal specimens from 18 infants/children (age range: 7 days to 123 months). Minute paraganglion nests (composed of chromogranin positive/serotonin negative chief cells and S-100 protein positive dendritic cells) were incidentally detected within the renal hilum primitive stroma (unilaterally) of two fetuses at 22 and 26 weeks. Sequestration and persistence of such paraganglion nests during renal growth and maturation would offer a basis for the rare occurrence of extra-adrenal paraganglioma involving the renal hilum/pedicle. Otherwise, no neuroendocrine cell was detected within the renal parenchyma or hilum, therefore not validating/sustaining the aforementioned hypothesis in the pathogenesis of renal carcinoid tumor.

Renal carcinoid and horseshoe kidney: a frequent association of two rare entities--a case report and review of the literature

We report the case of a primary renal carcinoid tumor associated with a horseshoe malformation in a 43-year-old man who presented with testicular pain. The tumor was centrally located and purely solid and had features ascribed to hindgut neuroendocrine neoplasia. The relative risk of developing a carcinoid tumor in a horseshoe kidney is estimated to be x82.