Table of Contents
Definition / general | Epidemiology | Pathophysiology | Clinical features | Radiology description | Case reports | Treatment | Gross description | Gross images | Microscopic (histologic) description | Microscopic (histologic) images | Cytology images | Positive stains | Negative stains | Electron microscopy description | Molecular / cytogenetics description | Differential diagnosis | Additional referencesCite this page: Andeen NK, Tretiakova M. Small cell neuroendocrine carcinoma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/kidneytumormalignantsmallcell.html. Accessed November 29th, 2023.
Definition / general
- High grade neuroendocrine neoplasm resembling small cell carcinoma of other organs
- Pure or admixed with high grade urothelial carcinoma of the kidney
- Rare, < 1% of renal neoplasms, ~ 50 cases reported
- Very rarely has been reported with renal cell carcinoma (J Urol 1998;159:1624, Gerontologist 1991;31:631)
Epidemiology
- Median age 59 - 65 years, may be seen with high grade urothelial carcinoma of the kidney (Hum Pathol 2011;42:1792, Clin Genitourin Cancer 2014;12:422)
Pathophysiology
- Likely arises from a multipotent stem cell
Clinical features
- Presentation: hematuria, back pain or abdominal pain (Clin Genitourin Cancer 2014;12:422, Hum Pathol 2011;42:1792)
- Highly aggressive behavior, often local or distant metastases (Cancer 2003;97:1436, Clin Genitourin Cancer 2014;12:422)
- Median survival 8 - 20 months (Cancer 2003;97:1436, Clin Genitourin Cancer 2014;12:422)
Radiology description
- Medullary location, lack of central necrosis in a large tumor (Magn Reson Imaging 2005;23:515)
Case reports
- 55 year old man with multicentric small cell neuroendocrine neoplasm of the renal pelvis and ureter (Indian J Urol 2008;24:571)
- 59 year old woman with primary small cell carcinoma of kidney after renal transplantation (Chin J Cancer Res 2013;25:608)
- 71 year old woman with combined small cell and transitional cell carcinoma of the renal pelvis (Arch Pathol Lab Med 1993;117:239)
- 76 year old woman with small cell carcinoma of the kidney (Arch Pathol Lab Med 2001;125:796)
- Primary oat cell carcinoma of the kidney (Am J Surg Pathol 1984;8:855)
Treatment
- Surgery
- Chemotherapy (platinum based, may receive same as pulmonary small cell carcinoma) +/- radiation (Cancer 2003;97:1436)
- Slightly improved survival of 17.3 months with neoadjuvant chemotherapy prior to nephrectomy (Clin Genitourin Cancer 2014;12:422)
Gross description
- Unifocal, centered in renal pelvis, usually invading perinephric adipose tissue (Hum Pathol 2011;42:1792)
- Median size 11 cm, mean 7.1 cm in another study (range from 2.3 to 23 cm)
Gross images
Microscopic (histologic) description
- Similar morphology to small cell carcinoma of the lung
- Diffuse growth of small cells with minimal cytoplasm, nuclear molding, indistinct nucleoli, high mitotic activity and apoptosis, lymphovascular invasion, necrosis
Microscopic (histologic) images
Positive stains
Negative stains
Electron microscopy description
- Scanty electron dense neurosecretory granules and desmosomes supporting epithelial differentiation (Cancer 1987;60:1809, Pol J Pathol 2014;65:15)
Molecular / cytogenetics description
- In urinary bladder, studies of coexistent urothelial carcinoma and small cell carcinoma show very similar loss of heterozygosity and X-inactivation patterns, suggesting that urothelial and small cell components derive from same cells in the urothelium, rather than transformation from a population of normal neuroendocrine cells (Am J Pathol 2005;166:1533)
Differential diagnosis
- Lymphoma: use immunostains to differentiate
- Metastatic small cell lung cancer: radiology, clinical history of primary lung tumor, absence of high grade urothelial component
- TTF1 is unlikely to have discriminatory value (Appl Immunohistochem Mol Morphol 2012;20:429, Clin Genitourin Cancer 2014;12:422, Zhonghua Bing Li Xue Za Zhi 2012;41:538)
- Other small blue cell tumors: PNET / Ewing's sarcoma, neuroblastoma, rhabdomyosarcoma, desmoplastic small round cell tumor
- Poorly differentiated urothelial carcinoma, plasmacytoid carcinoma, lymphoepithelioma-like carcinoma, metastatic Merkel cell carcinoma, synovial sarcoma
Additional references