What are the other Names for this Condition? (Also known as/Symptoms)

• High-Grade Renal Neuroendocrine Carcinoma
• Poorly-Differentiated Neuroendocrine Carcinoma of Kidney
• Renal Small Cell Neuroendocrine Carcinoma

What is Small Cell Carcinoma of Kidney? (Definition/Background Information)

• Small Cell Carcinoma of Kidney is a rare, aggressive, neuroendocrine type of renal carcinoma (kidney cancer) that develops from the multipotent stem cell from neural crest origin. The malignant tumor generally affects adult males and females; though, it is more common in older individuals
• The exact cause for the development of Small Cell Carcinoma of Kidney is presently unknown, but it may be due to genetic mutations. The risk factors are not well established, although the tumor is associated with congenital kidney malformations, teratomas, and urothelial carcinomas
• The typical symptoms of Small Cell Carcinoma of Kidney are blood in urine, a lump on the side, flank pain, unexplained fever and unexplained weight loss. The kidney tumor may give rise to complication such as spread of cancer to other parts of the body
• The treatment options include surgery, radiation therapy, chemotherapy, and targeted drug therapy. The prognosis of Small Cell Carcinoma of Kidney depends on the type and size of tumor, whether it is localized in the kidney or has metastasized (i.e., if the disease is in its early or advance stages, at the time of diagnosis)
• It may not be possible to prevent Small Cell Carcinoma of Kidney; although, in general, leading a healthy lifestyle, maintaining an ideal body weight, controlling one’s blood pressure, avoiding unnecessary medication, and avoiding smoking are all factors that can potentially help one reduce the risk for cancer development

The main types of kidney cancers include:

• Clear cell renal cell carcinoma: This is also called conventional renal cell carcinoma. 65% of renal cancers belong to this type
• Papillary renal cell carcinoma (PRCC): It is also called chromophil renal cell carcinoma. It constitutes 15% of all renal cancers. Some of these cancers can be seen in syndromes such as hereditary papillary renal cell carcinoma syndrome. A majority of individuals with PRCC, do not have a family history of kidney cancer
• Chromophobe renal cell carcinoma: They make up for 5% of the renal cancers. Usually, it is a slower-growing cancer when compared to other kidney cancers
• Collecting duct carcinoma of kidney: They make up for approximately 1% of the kidney cancers. The cancer arises from the collecting ducts of the kidney

Who gets Small Cell Carcinoma of Kidney? (Age and Sex Distribution)

• Small Cell Carcinoma of Kidney affects both men and women. However, it is reported to be more common in slightly older adults (age range 22-75 years; average age at diagnosis 59-65 years)
• The cancer is not specific to any ethnic or racial group

What are the Risk Factors for Small Cell Carcinoma of Kidney? (predisposing Factors)

In a majority of individuals, no clear-cut risk factors for Small Cell Carcinoma of Kidney have been established to date. In some cases, it may be associated with the following conditions:

• Horseshoe kidney, which is a congenital malformation of the kidney
• Teratoma tumor
• It can be present along with urothelial carcinoma

Some studies have shown that the following factors may predispose an individual to kidney cancer development:

• Family history of kidney cancer: If the cancer is present among close family members, then the risk of developing the cancer is increased
• Obesity
• High blood pressure
• Smoking
• Exposure to toxins, such as naphthylamine dye, asbestos, lead, polycyclic aromatic hydrocarbons, cadmium, and other chemical compounds
• Continuous use of certain medications such as non-steroidal anti-inflammatory drugs
• Long-term dialysis

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one's chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Small Cell Carcinoma of Kidney? (Etiology)

Currently, scientists do not know the definitive factor(s) causing Small Cell Carcinoma of Kidney.

• Studies have shown some genetic mutations in Renal Small Cell Carcinoma
• Some of these mutations include: Loss of heterozygosity and X-inactivation patterns

Research is underway to well-characterize these mutations.

What are the Signs and Symptoms of Small Cell Carcinoma of Kidney?

The signs and symptoms associated with Small Cell Carcinoma of Kidney may include:

• Small tumors usually do not cause any symptoms. But, occasionally they may become painful, if they compress the surrounding structure
• Blood in the urine (hematuria)
• Fatigue due to anemia
• A visible lump may be seen on the side of the abdomen
• The tumors range in size from 2-3 cm to 23 cm with an average size of 7-11 cm
• Fluid accumulation in the lower legs (pedal edema)
• Flank pain
• Unexplained weight loss
• Flushing, dyspnea, diarrhea due to hormone secretion (paraneoplastic syndrome)
  • If the tumors secrete adrenocorticotropic hormone (ACTH), then it can cause Cushing’s syndrome
  • If the tumors secrete vasoactive intestinal peptide (VIP), then it can cause watery diarrhea, hypokalemia, and achlorhydria
  • If the tumors secrete serotonin, then it can cause diarrhea, headache, increased body temperature and sweating, tremors, and flushing
• Night sweats, unexplained fever
• Generalized weakness and pain in the body
• Abnormal liver function test
• If the tumor is associated with paraneoplastic syndrome; then, the following may be noted:
  • Increased blood pressure (hypertension)
  • Increased calcium in blood (hypercalcemia)
  • Increased red blood cells (erythrocytosis)
  • Increased platelets (thrombocytosis)

The signs and symptoms may depend on the size of the kidney tumor.

How is Small Cell Carcinoma of Kidney Diagnosed?

A healthcare provider might employ one or several of the following tools to diagnose Small Cell Carcinoma of Kidney:

• Evaluation of the patient’s personal and family medical history
• A complete physical examination
• Blood tests such as complete blood count (CBC), serum calcium, serum albumin, liver function test (LFTs)
• Urine analysis such as albumin levels
• Plain X-ray of the abdomen
• Ultrasound scan of the abdomen
• Computed tomography (CT) scans of the kidneys
• Magnetic resonance imaging (MRI) and positron emission tomography (PET) scans may help differentiate between benign versus malignant tumors by detecting areas of metastasis (if any)

Although the above modalities can be used to make the initial diagnosis, a tissue biopsy of the tumor may be required to make a definitive diagnosis to begin treatment.

• The tissue for diagnosis can be procured in multiple different ways, and they include:
  • Fine needle aspiration (FNA) biopsy of the tumor: A FNA biopsy may not be helpful, because one may not be able to visualize the different morphological areas of the tumor. Hence, a FNA biopsy as a diagnostic tool has certain limitations, and an open surgical biopsy is preferred
  • Core biopsy of the tumor
  • Open biopsy of the tumor
• A tissue biopsy of the tumor is performed and sent to a laboratory for a pathological examination. A pathologist examines the biopsy under a microscope. After putting together clinical findings, special studies on tissues (if needed) and with microscope findings, the pathologist arrives at a definitive diagnosis. Examination of the biopsy under a microscope by a pathologist is considered to be gold standard in arriving at a conclusive diagnosis
• Biopsy specimens are studied initially using Hematoxylin and Eosin staining. The pathologist then decides on additional studies depending on the clinical situation
• Sometimes, the pathologist may perform special studies, which may include immunohistochemical stains, molecular testing, and very rarely electron microscopic studies to assist in the diagnosis
• Octreotide scintigraphy can help detect functional neuroendocrine tumor, and in some cases, liver metastasis. Functional neuroendocrine tumors are tumors that secrete hormones, such as ACTH, VIP, and serotonin, causing signs and symptoms such as the following:
  • ACTH causes Cushing’s syndrome
  • VIP causes watery diarrhea, low potassium levels (hypokalemia), and low production of gastric acid in stomach (achlorhydria)
  • Serotonin causes headaches, flushing, and diarrhea
• The differential diagnosis of Small Cell Carcinoma of Kidney may include:
  • High-grade renal cell carcinoma
  • High-grade transitional cell carcinoma

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Small Cell Carcinoma of Kidney?

The possible complications associated with Small Cell Carcinoma of Kidney include:

• Metastasis: The cancer can spread to other areas of the body such as lungs, bones, liver, and lymph nodes
• Complication due to surgery
• Side effects of chemotherapy (such as toxicity) and radiation therapy

How is Small Cell Carcinoma of Kidney Treated?

The treatment measures Small Cell Carcinoma of Kidney may include the following:

• Surgery:
  • In majority of individuals, surgical resection of the tumor with clear margins may result in a cure, especially if the tumor is confined to the kidney. In some cases, due to location of the tumor, a complete surgical removal may be difficult
  • Several different surgical procedures may be available, such as partial/radical nephrectomy or laparoscopic surgery, depending on the type, size, and location of the tumor
  • Postoperative care is important: One must maintain minimum activity levels, until the surgical wound heals
• Radiation therapy:
  • Radiotherapy can be used as primary therapy in situations where the tumor cannot be removed completely, or when the tumor reappears (recurrent Small Cell Carcinoma of Kidney) after surgery
  • Radiotherapy can also be used as an additional therapy after surgery, if there is a possibility of tumor recurrence after surgery, or if there are inadequate margins following surgery (possibility of tumor left behind)
• Chemotherapy can be used for treating Small Cell Carcinoma of Kidney under the following circumstances (depending on case by case basis):
  • The tumor cannot be removed completely (incomplete surgical resection)
  • Tumors that recur after surgery (recurrent Small Cell Carcinoma of Kidney)
  • Tumors that have spread to distant parts of the body (metastatic Small Cell Carcinoma of Kidney)
• Immunotherapy for Small Cell Carcinoma of Kidney: A patient’s immune system is activated to combat the cancer in this kind of therapy.
• Targeted drug therapy for Small Cell Carcinoma of Kidney: This kind of drug treatment targets and kills cancer cells specifically, not harming surrounding normal/healthy cells
• Arterial embolization of Small Cell Carcinoma of Kidney is a possible treatment option. Here the blood supply to the tumor is blocked resulting in tumor death

A long-term follow-up is required, because recurrence of the tumor at the site of surgery or metastasis in distant sites have been reported many years after surgery.

How can Small Cell Carcinoma of Kidney be Prevented?

Current medical research has not established a method of preventing Small Cell Carcinoma of Kidney.

• Regular health check-ups might help those individuals with a history of the condition in the immediate family and diagnose kidney cancers early
• Regular medical screening at periodic intervals with blood tests, radiological scans, and physical examinations for those who have already endured the tumor are helpful.

In general, preventive methods for Small Cell Carcinoma of Kidney include reducing the contributory risk factors, such as:

• Smoking
• Unhealthy diet and lifestyle
• Obesity
• Exposure to toxins
• Unnecessary medication

What is the Prognosis of Small Cell Carcinoma of Kidney? (Outcomes/Resolutions)

The prognosis of Small Cell Carcinoma of Kidney depends on the size and number of tumors, their localization, and spread. In general, the prognosis of this aggressive malignancy is poor.

• The most reliable prognostic factor of Small Cell Carcinoma of Kidney is dependent on whether the tumor can be completely removed through surgery with free margins or not (no traces of the tumor in adjoining tissue)
• The prognosis also depends upon a set of several factors, which include:
  • Stage of tumor: With lower-stage tumors, when the tumor is confined to site of origin, the prognosis is usually better with appropriate therapy. In higher-stage tumors, such as tumors with metastasis, the prognosis is poor. In majority of cases, the tumor is low stage.
  • The surgical respectability of the tumor (meaning, if the tumor can be removed completely)
  • Overall health of the individual: Individuals with overall excellent health have better prognosis compared with those with poor health
  • Age of the individual: Older individuals generally have poorer prognosis than younger individuals
  • Whether the tumor is occurring for the first time, or is a recurrent tumor. Recurring tumors have worse prognosis compared to tumors that do not recur
  • Response to treatment: Tumors that respond to treatment have better prognosis compared to tumors that do not respond to treatment
• When Small Cell Carcinoma of Kidney is diagnosed in the early stages, the possibility of survival increases and the prognosis is considered good with treatment
• In cases where both kidneys are affected, the prognosis is not projected to be favorable. Additionally, if the cancer has spread to other parts of the body, such as to the liver, lungs, or bone, the possibility of prolonged survival following diagnosis is limited

As with any tumor, it is important to have follow-up appointments with a physician to monitor for any returning tumors.

Additional and Relevant Useful Information for Small Cell Carcinoma of Kidney:

Please visit our Cancer & Benign Tumors Health Center for more physician-approved health information:

http://www.dovemed.com/diseases-conditions/cancer/