Small cell carcinoma of the kidney. A clinicopathologic, immunohistochemical, and ultrastructural study

Emerging Insights in Small-Cell Carcinoma of the Genitourinary Tract: From Diagnosis to Novel Therapeutic Horizons

Small-cell carcinomas (SCCs) of the genitourinary (GU) tract are rare malignancies with high metastatic potential. The most common primary sites are the bladder and prostate, but case reports of primary SCC of the kidney, ureter, and urethra also exist. The majority of patients present with gross hematuria, irritative or obstructive urinary symptoms, and symptoms of locoregionally advanced or metastatic disease at initial presentation. SCC of the bladder presents with nodal or metastatic involvement in the majority of cases and requires the use of platinum-based chemotherapy in combination with surgery and/or radiation. SCC of the prostate is most commonly seen in the metastatic castrate-resistant setting, and aggressive variant disease presents with a greater propensity for visceral metastases, osteolytic lesions, and relatively low serum prostate-specific antigen for volume of disease burden. Multiple retrospective and prospective randomized studies support the use of a multimodal approach combining platinum-based systemic therapy regimens with radiation and/or surgery for localized disease. This evidence-based strategy is reflected in multiple consensus guidelines. Emerging data suggest that small-cell bladder and prostate cancers transdifferentiate from a common progenitor of conventional urothelial bladder carcinoma and prostatic acinar adenocarcinoma, respectively. Areas of active basic research include efforts to identify the key genetic and epigenetic drivers involved in the emergence of small cell cancers to exploit them for novel therapies. Here, we review these efforts, discuss diagnosis and currently supported management strategies, and summarize ongoing clinical trials evaluating novel therapies to treat this rare, aggressive GU cancer.

Renal carcinoid tumor with liver metastasis followed up postoperatively for 9 years

Background

We describe a case of renal carcinoid tumor with liver metastasis followed up postoperatively for 9 years.

Case presentation

A 33-year-old man presented with left flank dull ache. On the abdominal computed tomography, a solid renal mass in the upper portion of the left kidney was detected. The patient had no other abnormal findings, such as suspected distant metastasis or lymph node metastasis. Radical nephrectomy was performed on 14/9/2005. Histological examination and immunohistochemical staining confirm primary renal carcinoid tumor. 9 years after radical nephrectomy, computed tomography of the abdomen demonstrated a 2 cm × 1.8 cm cyst mass in the right liver. Similar pathologic characteristics were found between the renal carcinoid tumor and liver tumor.

Conclusions

We present a primary renal carcinoid tumor with liver metastasis 9 years after radical nephrectomy. With literature review, renal carcinoid tumors exhibit heterogenous behavior.

Neuroendocrine tumors of the kidney: a single institution experience

BACKGROUND

Renal NETs, comprised of carcinoid tumors and small cell carcinomas, are a rare group of neoplasms. The rarity of these tumors pose a diagnostic and therapeutic challenge. Our purpose was to characterize the cases treated at a tertiary cancer center and to evaluate patient outcomes with the available treatment modalities.

PATIENTS AND METHODS

This was a retrospective study of patients with renal NETs seen at The University of Texas M.D. Anderson Cancer Center between January 1, 2001, and January 1, 2011. Patient and tumor data were analyzed using descriptive statistical methods.

RESULTS

Three cases of carcinoid tumors and 6 cases of small cell carcinoma were identified. The median age at diagnosis was 53 years for patients with carcinoid and 65 years for patients with small cell carcinoma. The most common presenting symptoms were back pain, flank pain, and hematuria. The morphological appearance of the tumor cells and their immunohistochemical reactivity for neuroendocrine markers and cytokeratin helped establish the diagnosis. Nephrectomy was the mainstay of treatment for carcinoid tumors, yielding good long-term results, even in the presence of metastases. Surgery and chemotherapy were used for small cell carcinoma of the kidney. The median overall survival for patients with small cell carcinoma of the kidney was 17.3 months.

CONCLUSION

Renal carcinoid tumors are indolent and are associated with prolonged survival, and small cell carcinomas of the kidney are aggressive tumors with relatively short overall survival. Although palliative in nature, cytotoxic chemotherapy is the mainstay of therapy and is best given before surgery.

Factors associated with the survival of patients with primary small cell carcinoma of the kidney

BACKGROUND

Primary small cell carcinoma (SCC) of the kidney is rare, and the factors associated with the survival of these patients are yet to be elucidated.

PATIENTS AND METHODS

We collected data on patients who were admitted to our hospital for SCC of the kidney in the last 22 years and of those in studies in the literature. Clinical characteristics were summarized using descriptive statistics. The associations of these factors with survival were evaluated using Cox regression models, and the hazard ratio of death was calculated.

RESULTS

This study included 45 patients (8 admitted to our hospital and 37 from studies in the literature) with SCC of the kidney. The overall median survival time was 9.9 months (range 6.9-31.6). Data on demographics, clinical symptoms, tumor staging, and tumor characteristics recorded at the time of diagnosis were not associated with survival. Among the different treatment modalities applied, cisplatin-based chemotherapy afforded a strong survival advantage (hazard ratio = 0.35, p = 0.022). However, patients with early local recurrence (hazard ratio = 19.13, p = 0.012) and early distant metastasis (hazard ratio = 10.93, p = 0.003) after primary treatment showed significantly poor survival.

CONCLUSIONS

Patients with primary SCC of the kidney generally presented with large, advanced-stage tumors and showed poor survival. Early detection of the tumor, use of cisplatin-based chemotherapy, and careful follow-up for local recurrence or frequent metastasis within 6 months after the primary treatment could be important for improving overall patient survival.

Small cell carcinoma of the kidney: a clinicopathologic study of 14 cases

Small cell carcinoma of the kidney is distinctively rare. We searched pathology files in 2 institutions and found 14 cases of renal small cell carcinoma. The patients' mean age at diagnosis was 59 years (range, 22-75 years); 8 were women, and 6 were men. Patients usually presented with hematuria (n = 6) and abdominal pain (n = 5). The mean tumor size was 7.1 cm (range, 3.5-14.0 cm). The small cell carcinoma was pure in 9 cases and mixed with high-grade urothelial carcinoma in 5 cases. None was associated with any type of renal cell carcinoma. Tumor necrosis was present in all cases, and lymphovascular invasion was identified in 6 cases. The tumor invaded the perinephric adipose tissue in 13 cases and was confined to the kidney in only 1 case. Lymph node metastases were identified in all patients who underwent lymph node dissection (5/5). On immunostains, the small cell carcinoma cells were positive for pancytokeratin (11/12), chromogranin (6/9), and synaptophysin (8/9). Follow-up data were available for 13 patients, and 11 died of small cell carcinoma at a mean of 15 months (range, 4-31 months) after diagnosis. Of the 2 surviving patients, 1 was alive at 5 months after diagnosis, and the other, whose disease was confined to the kidney, was alive with no evidence of disease at 137 months. In summary, renal small cell carcinoma is a highly aggressive disease that often presents at an advanced stage with widespread metastases. Patients usually have a poor clinical outcome despite multimodal therapy. The frequent coexistence of small cell carcinoma with urothelial carcinoma suggests that renal small cell carcinomas may evolve from a preexisting urothelial carcinoma.

Primary large cell neuroendocrine carcinoma of the kidney

We report a case of a 56-year-old male with a primary large cell neuroendocrine renal carcinoma. Grossly, the left kidney was enlarged by a solid tumor that measured 145 x 125 x 100 mm. Histologically, the tumor consisted of large cells with a moderate to abundant amount of eosinophilic cytoplasm. The nuclei were irregular, some of them with finely or coarsely granular chromatin, others with vesicular chromatin and prominent nucleoli. The tumor cells showed multiple mitotic figures (up to 32 mitoses/10 HPF). In some areas, the tumor cells were arranged in solid sheets; however, the predominant pattern was solid-alveolar, trabecular and cribriform. Large areas of tumor necrosis were found. Immunohistochemically, the tumor cells were positive for synaptophysin, CD56 and CD57. Cytokeratin AE1/AE3, vimentin and CD10 were positive only focally. Chromogranin showed weak cytoplasmic positivity in rare tumor cells. Cytokeratin CAM5.2, cytokeratin 34betaE12, BerEP 4, EMA, TTF-1, cytokeratin 7, cytokeratin 20, calretinin, serotonin, somatostatin, gastrin, calcitonin, glukagon and insulin were negative. Primary large cell neuroendocrine carcinoma of the kidney is a rare tumor. To the best of our knowledge, only 3 cases of a tumor of this type have been reported to date.

Primary small cell carcinoma of the kidney with tumour thrombus extension into the inferior vena cava and pulmonary artery: a case report and review of the literature

Renal small cell carcinoma is a rarely seen malignant neoplasm with high propensity for distant metastasis and aggressive behaviour showing combined characteristics of neuroendocrine and epithelial neoplasia in terms of immunohistochemistry and ultrastructure. To the best of our knowledge this is the first report of primary small cell carcinoma of the left kidney with tumour thrombus extending to the inferior vena cava and pulmonary artery to undergo left radical nephrectomy and tumour thrombectomy under extracorporeal circulation and deep hypothermic circulatory arrest. The patient was a 33-year old male. He was discharged from hospital 10 days following the procedures and remained alive at the time of writing, over 7 months after discharge. Light microscopy, immunohistochemistry and the survival outcome of this case are presented and these are discussed in the context of a review of similar cases in the current literature. This case demonstrated that, in the absence of distant metastases, renal small cell carcinoma with tumour thrombus does not contraindicate surgery.

Primary small cell neuroendocrine carcinoma of the kidney: morphological, immunohistochemical, ultrastructural, and cytogenetic study of a case and review of the literature

Poorly differentiated neuroendocrine carcinomas (PDNECs) of the kidney are extremely rare high-grade cancers accounting for only 42 cases reported in the literature. In this paper, we describe the morphological, immunohistochemical, ultrastructural, and for the first time, cytogenetic features of a renal PDNEC. In addition, we have reviewed the literature and compared the published clinicopathological data with our morphological and genetic results. The tumor arose within the kidney parenchyma and showed the typical histological features of a pure small cell PDNEC. Fluorescence in situ hybridization study demonstrated a complex chromosomal assessment indicative of a high degree of chromosome instability with gain of multiple chromosomes, loss of p53, and amplification of myc gene. These results suggest that renal PDNEC has a different genetic background to renal clear cell carcinoma, mainly characterized by the loss of the short arm of chromosome 3. Conversely, genetic alterations seem to resemble those of type 2 papillary renal cell carcinoma. The review of the literature demonstrated that PDNECs are associated with poor prognosis and that parenchymal tumors show some differences from those arising in the pelvis, in that parenchymal tumors are purely neuroendocrine while pelvic tumors are mostly mixed neuroendocrine-exocrine neoplasms.

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.

The pathology of extrapulmonary small cell carcinoma

Extrapulmonary small cell carcinomas (EPSCCs) are uncommon malignant neoplasms with a reported incidence of 0.1% to 0.4% in the United States. Since their first description in 1930, they have been seen in nearly every organ system. Like their more common pulmonary counterparts, EPSCCs are thought to arise from a multipotential stem cell. However, there is recent molecular evidence that small cell elements may arise as a late-stage phenomenon in the genetic progression of more organ-typical carcinomas. The morphologic, immunohistochemical, and ultrastructural features are similar to those described in pulmonary small cell carcinomas (PSCCs). The differential diagnosis of EPSCC includes PSCC, other neuroendocrine tumors, small round blue cell tumors, metastatic melanoma, lymphoma, and poorly differentiated non-small cell carcinomas. Molecular alterations reported to occur in EPSCCs include abnormalities described in PSCC and changes found in carcinomas more typically encountered in the organ from which they arise. In this article we discuss the pathology of EPSCC with a review of theories of histogenesis, sites of occurrence, diagnostic features, differential diagnosis, molecular alterations, and clinical behavior.

Small Cell Cancer of the Pleura, Kidney, and Thymus

Small cell carcinoma is a distinct clinicopathologic entity that usually arises in the lung but also can originate in extrapulmonary sites, such as the pleura, thymus, and kidney. Small cell carcinoma of the kidney and renal pelvis is rare. Most patients present with large tumors and have evidence of extensive locoregional spread and distant metastases, despite a short duration of symptoms. Although nephrectomy has been used for treatment it does not appear to confer any significant benefit. Cisplatin-based chemotherapy has improved the median survival from 8 months to 20 months. Only isolated cases of small cell carcinoma of the pleura and thymus have been reported. Both tumors have a tendency for aggressive local invasion and distant metastases. Surgery, radiation, and chemotherapy have been used in the management of these tumors with variable results.

Curative resection of a small cell carcinoma of the pancreas: report of a case of long survival without chemotherapy

A 41-year-old asymptomatic man was, by chance, diagnosed as having a mass in the left upper quadrant of the abdomen by ultrasound. Computed tomography and magnetic resonance imaging showed a slightly enhanced heterogeneous mass, measuring about 5 cm in diameter, adjacent to the pancreas tail and spleen. On abdominal angiography the tumor was found to be fed by the splenic artery, and no encasement was observed. At operation the tumor was connected to the pancreas tail and attached to the spleen, and no metastasis was evident. As a result of these observations, a curative resection was performed. On histological examination the tumor cells had no ductal or architectural organization and were continuous to the normal pancreatic tissues. The cells were negative for Grimelius argylphile and the periodic acid schiff stain. Immunohistochemistry indicated that the tumor cells were positive for keratin and epithelial membrane antigen, but negative for chromogranin A, vimentin, alpha1-antitrypsin and alpha1-antichymotrypsin. The tumor was diagnosed as a small cell carcinoma of the pancreas, which is a rare disease. In previously reported cases curative resection of the tumor had not been possible because of its rapid progression and metastasis, and the prognosis is generally very poor. In our case, however, curative resection of the tumor was done, and the patient is healthy with no signs of recurrence for 56 months after the operation and with no additional therapy.

Low-grade tubular-mucinous renal neoplasm with neuroendocrine differentiation: A histological, immunohistochemical and ultrastructural study

Low-grade tubular-mucinous renal neoplasm (LGTMRN) was recently established as a distinct carcinoma classification. A 70-year-old, female traffic accident victim underwent a detailed examination that disclosed a huge mass in the lower pole of the left kidney. The patient underwent a nephrectomy based on a diagnosis of renal tumor. Macroscopically, the tumor was well demarcated and a whitish color with focal hemorrhage. Histological examination showed that tumor cells proliferated through tubular, trabecular, and solid growth patterns in the mucinous background. Focally, foci of clear cells or the proliferation of spindle cells was also observed. Nuclei were generally round and uniform in size. No abnormal mitotic figures were identified. Immunohistochemically, tumor cells were diffusely positive for AE1/AE3, vimentin and chromogranin A, and focally positive for cytokeratin (CK) 18, CK19, Ulex europaeus agglutinin-1, epithelial membrane antigen, neuron-specific enolase (NSE), CD9 and CD57. Ultrastructurally, tumor cells contained a moderate number of mitochondria, rough endoplasmic reticulum and dense-core granules. No renin granules or glycogen were observed. Microvilli were focally seen. Our results render further evidence that LGTMRN is a distinct entity from the hitherto established renal neoplasms. Foci of clear cells and neuroendocrine differentiation should be added to the histological spectrum of LGTMRN.

Therapy and outcome of small cell carcinoma of the kidney: report of two cases and a systematic review of the literature

BACKGROUND

Primary small cell carcinoma originating from the kidneys is an extremely rare neoplasm. The authors described two patients with small cell carcinoma of the kidney and provided a systematic review of the literature to detail the clinical characteristics and therapy of this rare tumor.

METHODS

MEDLINE and CANCERLIT literature search was performed from 1966 to 2002 for articles on small cell carcinoma of the kidney. Twenty-two patients with small cell carcinoma of the kidney and renal pelvis were reviewed.

RESULTS

The median age at diagnosis was 62 years and there was a female preponderance (male:female ratio, 1:3.4). Abdominal pain (70%) was the most commonly reported symptom. Distant metastases were present in 32% of patients at the time of diagnosis. Surgery and systemic chemotherapy were the primary therapeutic modalities utilized (nephrectomy alone: 9 patients; nephrectomy and chemotherapy: 10 patients; chemotherapy alone: 3 patients). The median survival was 8 months (range, < 1-101 months). The use of platinum-based chemotherapy was predictive of an improved overall survival (median survival was 20 months in patients receiving a platinum-containing regimen compared with 8 months in those who did not receive platinum; P = 0.02).

CONCLUSIONS

Small cell carcinoma of the kidney is an extremely rare neoplasm that resembles its counterparts arising from the tracheo-bronchial and other extrapulmonary sites in its aggressive behavior and high propensity for locoregional and distant dissemination. Clinical presentation is usually late in the course of the disease. The use of platinum-based chemotherapy has been associated with tumor regression and prolonged survival.

Primary small cell carcinoma of the kidney

Primary small cell carcinomas of the kidney are rare, locally aggressive and fatal neoplasms. Approximately half of the reported cases show combined features of transitional cell carcinoma. We reported an unusual case of primary small cell carcinoma of the kidney and studied with light microscopy, immunohistochemistry and flow cytometry.

[Neuroendocrine renal tumor. An unusual case. Review of the literature]

The neuroendocrine renal tumors are of extremely strange presentation. We present a review of the literature published on this pathology.

Primary mammary small-cell carcinoma: a molecular analysis of 2 cases

Primary small-cell carcinoma of the breast is an exceedingly rare variant of breast carcinoma whose genetic profile has not been previously investigated. We report the molecular features of 2 cases of small-cell carcinoma of the breast: 1 with an adjacent intraductal carcinoma, and 1 with prior pleomorphic lobular carcinoma in situ. Laser capture microdissection followed by loss of heterozygosity (LOH) analysis revealed identical molecular alterations at multiple chromosomal regions, including BRCA-1, BRCA-2, p53, and retinoblastoma gene loci, in 1 case of small-cell carcinoma and its adjacent intraductal component. Additionally, LOH in 1 or both small-cell carcinomas was detected at 3p, 4q31.2-qter, 8p21-24, 11q13 (MEN-1 locus), 11q23.3, 11q24.1-25, 16q24.1 (H-cadherin locus), and 17q25. The results of our molecular analysis suggest that genetic changes in mammary small-cell carcinoma resembled those seen in both invasive ductal carcinomas and pulmonary small-cell carcinoma. Second, mammary small-cell carcinoma is clonally related to ductal carcinoma in situ and might represent an example of divergent differentiation occurring in a multipotential neoplastic stem cell.

Primary malignant neuroepithelial tumors of the kidney: a clinicopathologic analysis of 146 adult and pediatric cases from the National Wilms' Tumor Study Group Pathology Center

Primary malignant neuroepithelial tumors of the kidney (NETKs) comprise a group of primitive, highly malignant neoplasms that histologically and clinically are not well characterized. A large cohort of 146 of these tumors, occurring in adults and children, has been collected at a single depository site, the National Wilms' Tumor Study Group (NWTSG) Pathology Center. The authors undertook a systematic retrospective review of the histologic, ultrastructural, and clinical features of these tumors, based on materials collected by the NWTSG and the consultation files of one of the authors (J.B.B.). Histologic features were generally those of primitive neural tumors with varying amounts of rosettes and neuropil; however, a large proportion of cases displayed unusual features such as spindle cells, ganglion cells, clear cell sarcoma-like foci, rhabdoid cells, epithelioid cells, and organoid foci. CD99 staining had been performed on 69 cases and showed membranous staining in 65. The NETKs were present in patients with a wide age spectrum, ranging from 1 month to 72 years (median, 18 years). EWS/FLI1 fusion analysis using reverse transcriptase-polymerase chain reaction and immunohistochemical stains for cytokeratin, chromogranin, and epithelial membrane antigen were performed successfully on a subset of 45 cases with available paraffin blocks. Only 13 of the 45 were fusion-positive, and there was no correlation between fusion status and histology, presence of rosettes, ultrastructural features, or cytokeratin positivity. CD99-negative cases were usually fusion-negative (six of seven cases), and all three chromogranin-positive cases were fusion-negative. Tumor staging, performed on 72 clearly defined and quantifiable cases by using NWTSG criteria, indicated that these are aggressive tumors, because only six were Stage 1, compared with 16 Stage 2, 31 Stage 3, and 19 Stage 4 lesions. The authors conclude that NETKs are a somewhat diverse group of generally aggressive, high-grade lesions that may present in a wide age range and are difficult to characterize without immunohistochemistry and cytogenetics/molecular biology.

Wilms' tumor in the adult--report of a case and review of the literature

Wilms' tumor is rare in adults. Its histology, grading and staging are identical to those in children. Investigators agree on a combined modality approach in the treatment of adult Wilms' tumor (AWT), but differ on how aggressive it should be. Some advocate adopting the current pediatric protocols which take into account tumor stage and grade. Others recommend using advanced disease regimens for all stages and grades. We report on an 18 year-old male with stage IV favorable histology Wilms' tumor. The patient underwent radical nephrectomy and received postoperative radiotherapy with intensive four-drug chemotherapy. He had one relapse after 12 months which was successfully treated with chemotherapy and radiotherapy. He remains in remission without relapses 36 months after the initial diagnosis. The genetics of Wilms' tumor has been well studied in children but is practically unknown in adults; karyotype and molecular genetic studies in this case were normal.

Genitourinary small cell carcinoma: determination of clinical and therapeutic factors associated with survival

PURPOSE

We assessed the prognostic impact of genitourinary small cell carcinoma tumor and patient characteristics, and therapy.

MATERIALS AND METHODS

We retrospectively reviewed the records of 180 patients with genitourinary small cell carcinoma in which patient and tumor characteristics, therapy, followup duration and survival status had been documented. Patient age, sex, primary site, histological features, tumor size, stage, locoregional therapy, systemic chemotherapy and hormonal manipulations were analyzed for association with survival.

RESULTS

There were 106 cases of bladder, 60 prostatic, 8 renal and 6 ureteral small cell carcinoma. Median survival was 10.5 months overall, and 7 and 13 months for prostatic and bladder small cell carcinoma, respectively (p <0.0001 log rank analysis). In all cases metastatic disease at presentation (p <0.008, risk ratio 1.9) predicted poor survival on multivariate analysis. Radical surgery (p <0.0001, risk ratio 0.34) and cisplatin chemotherapy (p <0.0001, risk ratio 0.20) were the only factors that predicted improved survival on multivariate analysis. For prostatic small cell carcinoma primary surgical therapy (p <0.012, risk ratio 0.46) was the only parameter that predicted survival on univariate analysis. For bladder small cell carcinoma only cisplatin chemotherapy (p <0.0001, risk ratio 0.15) predicted survival on multivariate analysis.

CONCLUSIONS

Genitourinary small cell carcinoma has a poor prognosis, which is worse in prostatic than bladder disease. Patient and tumor characteristics were not determinants of survival when prostatic and bladder small cell carcinoma were analyzed individually. For prostatic disease only primary surgical therapy was associated with prolonged survival, while for bladder disease cisplatin chemotherapy was associated with a favorable prognosis. We recommend considering primary surgical therapy for prostatic and cisplatin based chemotherapy for bladder small cell carcinoma.

Renal small cell carcinoma (neuroendocrine carcinoma) without features of transitional cell carcinoma

Seventeen cases of renal small cell carcinoma have been reported in the literature. Approximately half of the reported cases show combined features of transitional cell carcinoma. Presented herein is a case of renal small cell carcinoma in a 37-year-old Japanese male who had been treated for 10 years with famotidine for duodenal ulcer. He suffered from sudden-onset chest pain at presentation and myxoma of the right atrium was suspected. He was treated by atriotomy and a tumor was removed from the right atrium and pulmonary artery. Histological examination, however, revealed it to be small cell carcinoma. Accordingly, a radical operation was performed for the removal of a tumor found in the right kidney. Histological examination of the tumor confirmed the presence of renal small cell carcinoma without any features of transitional cell carcinoma. It is reported that long-term administration of an histamine 2 (H2) receptor antagonist may produce carcinoid tumors in rodents and enterochromaffin-like cell hyperplasia in humans. The possible relationship between neuroendocrine carcinoma and H2 receptor antagonist therapy is discussed.

Small cell undifferentiated carcinoma of the pancreas

Small cell undifferentiated carcinoma of the pancreas is a rare neoplasm: Only 12 cases have previously been documented. This paper describes the clinical evolution, immunohistochemical profile, and ultrastructural features of a case occurring in a 37-year-old woman.

Small cell carcinoma of the kidney: case report

An 83-year-old female diagnosed with small cell carcinoma of the kidney is reported on. The clinical picture was similar to that seen with transitional cell carcinoma of the renal pelvis. A right nephroureterectomy was performed and a histological examination revealed similar morphological features to those of small cell carcinoma of the lung. Neuroendocrine differentiation was proven by a positive immunoreaction to neuron-specific enolase. A review of the literature indicated that in the urinary tract, most of the cases of small cell carcinoma occurred in the urinary bladder, with this case being the eleventh reported case of small cell carcinoma originating in the kidney. As with many of the other cases of small cell carcinoma of the urinary tract, this patient's tumor was associated with both adenomatous and squamous differentiation. The patient died 2 months after surgery, prior to any chemotherapy administration.

Primary carcinoid tumor of the kidney with special reference to its histogenesis

A case of primary carcinoid tumor of the kidney occurring in a 66-year-old woman is reported. The tumor was 10 x 10 x 9 cm in size, solid, yellowish-white in color, and associated with massive hemorrhagic necrosis. Histologically, it was composed of trabecular and anastomosing ribbon-like nests. The tumor cells showed argyrophilicity with the Grimelius stain and cytoplasmic positivity for neuroendocrine markers, (including chromogranin A, neuron-specific enolase, synaptophysin and Leu-7), prostatic acid phosphatase, keratin and vimentin. Numerous cytoplasmic neurosecretory granules were demonstrated ultrastructurally. These histologic and immunohistochemical findings are consistent with the theory that this tumor has a common phenotype with that of carcinoid tumor arising from the hindgut or cloaca.

Primary small cell neuroendocrine carcinoma of the kidney

The histological, immunohistochemical, and ultrastructural features of a primary small cell neuroendocrine carcinoma of the renal parenchyma are described. Tumor cells were positive for cytokeratin, neuron-specific enolase, and Leu 7, but Grimelius- and chromogranin-negative. They also exhibited positivity with anti-MIC2 antibody. By electron microscopy, tonofibrils, primitive desmosomes, and dense-core granules with a neuroendocrine appearance were present. This is only the 7th recorded example of such a tumor at this site, which showed an aggressive course characterized by widespread bony metastases.

Clear cell sarcoma of kidney. Two cases in adults

BACKGROUND

Clear cell sarcoma of kidney (CCSK) is an aggressive renal tumor occurring most frequently in the second and third years of life. Although it has been reported in the literature in patients as old as 21 years of age, there has been no report focusing on adults with CCSK. The authors describe two cases of CCSK in men and the findings at autopsy.

METHODS AND RESULTS

Histologically, the renal tumors consisted of a homogeneous proliferation of polygonal or short spindle cells with faintly eosinophilic cytoplasm supported by a network of small vessels. Ultrastructurally, clusters of tumor cells were surrounded by collagen bundles. Elongated cytoplasmic processes, dilated rough endoplasmic reticulum, and intermediate filaments in the cytoplasm; primitive desmosome-like junctional structures; and incomplete basal lamina were observed. Immunohistochemically, tumor cells had positive results only for vimentin. Cytokeratins, epithelial membrane antigen, desmin, myoglobin, S-100 protein, neuron-specific enolase, and chromogranin A were not detected in the tumor cells. Both patients died within 2 years of onset of disease, and autopsy showed widespread metastases, especially in the soft tissue and bone.

CONCLUSIONS

Morphologic findings and an aggressive clinical course with metastasis to the bone and soft tissue are supportive of the diagnosis of CCSK in these patients.

Extrapulmonary and pulmonary small-cell carcinoma: tumor biology, therapy, and outcome

Extrapulmonary small-cell cancer is a distinct clinicopathological entity from small-cell anaplastic carcinoma of the lung. Approximately 1,000 cases have been projected annually in the United States, which represents an overall incidence of between 0.1% and 0.4% of all cancer. Not surprisingly then, little information is available regarding the treatment of this disease, which presents a challenge to the clinician when it is regionally confined. The majority of patients with extrapulmonary small-cell neoplasms have only been treated with local modalities of therapy, surgery, radiation, or a combination of both. Prolonged survival is not infrequent, which is in contrast to the experience for small-cell lung cancer and surprising given our current systemic approach to patients with this disease. This report will summarize the similarities and differences in biology, natural history, and clinical characteristics of patients with extrapulmonary small-cell cancer and small-cell anaplastic carcinoma of the lung. The histogenesis of small-cell cancer is briefly reviewed. A general therapeutic approach to patients with small-cell lung cancer is reported. Lastly, recommendations for therapy of patients with regionally confined extrapulmonary small-cell cancer by primary site are outlined.

Carcinoid tumor of the kidney with morphologic and immunohistochemical profile of a hindgut endocrine tumor: report of a case

A 54-year-old man underwent a radical nephrectomy for a presumed renal cell carcinoma. The tumor was large, showed areas of cystic degeneration and calcification, and had completely obliterated the normal renal parenchyma. The light microscopic appearance was atypical for renal cell carcinoma, and when electron microscopy revealed innumerable neurosecretory granules a diagnosis of carcinoid tumor was made. The tumor cells were argentaffin- and argyrophil-negative but were chromogranin-, neuron-specific enolase-, and leu-7-positive. When tested with a battery of antibodies against specific polypeptide hormones, the tumor exhibited diffuse pancreatic polypeptide and focal somatostatin immunoreactivity. Our case represents only the 16th case of carcinoid tumor of the kidney to be reported and the first with demonstrated pancreatic polypeptide immunoreactivity. The predominantly trabecular histology, nonreactivity with silver stains, and immunohistochemical profile of this case are common characteristics of hindgut carcinoids, suggesting that, like rectal carcinoids, renal carcinoids are tumors of hindgut endocrine cells.

Small cell carcinoma of the genitourinary tract: an immunohistochemical, electron microscopic and clinicopathological study

We examined 13 cases of small cell carcinoma of the genitourinary tract to evaluate and compare the immunocytochemical and ultrastructural features as well as the clinicopathological behavior. Immunohistochemical stains revealed that neuron specific enolase and chromogranin showed differences in staining between the bladder and prostate, as well as between the small cell and adenocarcinomatous components of the prostate. Also, synaptophysin was negative over-all in 12 of 13 cases. Epithelial membrane antigen, carcinoembryonic antigen and keratin showed strong focal positivity within the small cell component. Electron microscopy was performed in 4 cases, with 3 demonstrating neurosecretory granules. Clinically, 6 of the 7 patients with adenocarcinoma/small cell carcinoma of the prostate did poorly, all with a survival of 15 months or less. Of 5 patients with transitional cell/small cell carcinoma of the bladder 2 fared better (both had no evidence of disease at 12 months and 11 years, respectively). Based upon the immunostaining and electron microscopic findings, small cell carcinoma of the genitourinary tract is heterogeneous in appearance and, therefore, may arise from a multipotential cell of origin. This cell of origin may be organ-specific, as demonstrated by the variability in staining characteristics among the prostate, bladder and kidney, as well as by the differences in the clinical behavior of these malignancies. Small cell carcinoma of the prostate has a poor prognosis, while small cell carcinoma of the bladder may portend a better prognosis if diagnosed at an early stage.

Immunohistochemical study of jaw cysts: different existence of keratins in odontogenic and non-odontogenic epithelial linings

Keratins and secretory component (SC) were immunohistochemically examined in fresh tissue samples from 45 odontogenic and 35 non-odontogenic cysts. Lining epithelia of almost all cases contained keratins which reacted with polyclonal antibodies (Dako, Bio-Science), and no difference could be found between the two groups of lesions. By staining with two monoclonal antibodies against keratins, i.e., RGE53 (Bio-Science) and RKSE60 (Bio-Science), it was revealed that the epithelia of non-odontogenic cysts, which were columnar epithelium in most cases, had fully and positively reacted with RGE53, while none of the cases was positive for RKSE60. In contrast, the squamous linings of odontogenic cysts except for two cases did not react with RGE53, and few cases possessed RKSE60-reactive keratin. SC was also contradictory. All non-odontogenic cysts exhibited SC. Regarding each pair of non-odontogenic and odontogenic cysts covered with RGE53 and SC-positive, and RKSE60-negative squamous epithelium, it seemed reasonable from the staining results to conclude that the squamous linings were metaplastic from the columnar epithelium. Based on the results, concomitant examinations of SC with keratins will be helpful in deciding the epithelial derivation of jaw cysts.

Small cell carcinoma of the renal pelvis: a clinicopathological, morphological and immunohistochemical study of 2 cases

Two women, 62 and 66 years old, with combined small cell carcinoma and transitional cell carcinoma of the renal pelvis are reported. The clinical picture was similar to that seen in conventional transitional cell carcinoma. A brief review of the literature indicates that in the urinary tract, small cell carcinoma occurs most commonly in the bladder and is exceedingly rare in the renal pelvis; only 2 cases have been reported previously. The morphological spectrum of the small cell carcinomatous component is similar to that seen in lung tumors. Neuroendocrine differentiation of the small cell carcinoma component was supported by a positive immunoreaction to neuron-specific enolase in both cases and to synaptophysin in 1. One patient died with metastases 8 months after diagnosis, and 1 was alive with clinical evidence of lymph node metastases and contralateral papillary transitional cell carcinoma of the renal pelvis 16 months after diagnosis.

Calcitonin free oat-cell carcinoma of the thyroid gland

Two cases of primary oat-cell carcinoma of thyroid, in a 63-year-old woman and a 73-year-old man, are described. Case 1 was a compound tumour with the oat-cell component merging with a papillary component. Both tumours, in addition to histological features consistent with oat-cell carcinoma, showed immunohistochemical positivity with anti-chromagranin A and anti-synaptophysin antisera. Negative results were obtained when anti-calcitonin and anti-thyroglobulin antisera were employed. Using in situ hybridization, chromogranin A and B messenger RNAs were localized with biotinylated oligonucleotide probes. In contrast, with in situ hybridization, no localization for calcitonin messenger RNA was seen using radioactive and biotinylated probes. It is concluded that these calcitonin-free, small-cell carcinomas should be considered separately from medullary thyroid carcinomas and be regarded as a distinct entity, probably the thyroid equivalent of oat-cell carcinomas of the lung.