Presented by: Dr. Neela
6 October 2010 2
Kidney cancers account for about 3%
of all cancer cases as well as about 3%
of all cancer deaths.
38,890 new diagnoses and 12,840
deaths were expected in 2006.
$1.9 billion is spent in the United
States each year on treatment of
6 October 2010 3
Most renal tumors arise from the renal parenchyma
(referred to as renal cell tumors, renal cortical
tumors, or renal parenchymal tumors),
A much smaller number arising from the
urothelium of the renal collecting system (urothelial
carcinoma or transitional cell carcinoma [TCC]) or
the mesenchyma (eg, angiomyolipoma, leiomyoma,
Benign renal parenchymal tumors include renal
oncocytoma (5%) and the rarer metanephric
adenoma, metanephric adenofibroma, and papillary
renal cell adenoma.
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Malignant renal cell tumors occur nearly twice
as often in men as in women
The age at diagnosis is generally older than 40
years; the median age is in the mid-60s
Bilateral multifocal renal tumors are present in
approximately 5% of patients with sporadic
As in solitary disease, conventional clear cell
histology is the most common histologic
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Kidney Tumors Presentation
Common symptoms that lead to the
detection of a renal mass are hematuria,
flank mass, and flank pain.
Less frequently, patients present with signs
or symptoms resulting from metastatic
disease, such as bone pain, adenopathy, and
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Benign renal neoplasms
Benign renal neoplasms that occur in adults
constitute heterogeneous group of tumors with
characteristic histology and variable
The 2004 World Health Organization (WHO)
classification schemata categorizes benign renal
neoplasms on the basis of histogenesis (cell of
origin) and histopathology. Renal neoplasms are
thus classified into renal cell,
metanephric, mesenchymal, and mixed epithelial
and mesenchymal tumors.
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APPENDIX 1: World Health Organization
(WHO) Histological Classification of
Benign Renal Neoplasm's
Renal Cell Tumors
adenoma Angiomyolipoma Cysticnephroma
stromal tumor Hemangioma
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Renal Cell Neoplasms
Oncocytoma is a benign renal cell neoplasm that
accounts for approximately 5% of all adult primary
renal epithelial neoplasms. Most tumors occur
sporadically in asymptomatic patients.
Oncocytoma is histologically composed of nests
and acini of large polygonal cells with
cytoplasm . Oncocytomas typically appear as
solitary, well-demarcated, unencapsulated,
fairly homogeneous renal cortical tumors.
Hemorrhage may be found in up to 20% of cases. A
spoke-wheel pattern of feeding arteries associated
with a homogeneous nephrogram is a
characteristic finding on catheter angiography.
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Fig. 1 —72-year-old man with hereditary oncocytosis syndrome.
Coronal contrast-enhanced CT scan during nephrographic
phase shows bilateral solid renal masses (arrows) that were
characterized as oncocytomas on histopathology.
Fig. 2 —64-year-old man with histologically proven
oncocytoma. K = kidney. Axial fat-saturated, gadolinium-
enhanced T1-weighted 3D gradient-refocused echo image
shows right kidney mass (arrow) with hypointense central
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Papillary adenomas are the most common renal
epithelial neoplasms. According to autopsy
series, approximately 40% of patients older
than 70 years harbor renal adenomas. Papillary
adenomas are alsocommonly found in patients
with acquired renal cystic disease and in patients
undergoing long-term hemodialysis.
By definition, papillary adenomas measure 5
mm or less. They are usually subcapsular and
solitary. Adenomas are
histologically characterized by papillary or
tubular cytoar-chitecture and frequent
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Cytogenetic changes of papillary adenomas
include loss of the Y chromosome and
combined trisomy of chromosomes 7 and 17.
Histologic and genetic abnormalities of renal
adenomas are indistinguishable from
Papillary adenomas are extremely small (< 5
mm) and may not be distinguished from
other renal tumors (particularly RCC) and
pseudotumors on imaging studies.
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Metanephric neoplasms are a
heterogeneous group of benign
renal neoplasms that include
metanephric adenoma (epithelial
tumor), metanephric stromal tumor
(stromal neoplasm), and
metanephric adenofibroma (mixed
epithelial and stromal neoplasm).
These tumors are histogenetically related
to Wilms' tumor and arepostulated to
represent the most hyperdifferentiated,
benign end of the nephroblastoma
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Metanephric adenoma is a benign renal
neoplasm with peak age of occurrence in
the fifth or sixth decade and a 2:1
female preponderance. Metanephric
adenoma is asymptomatic in
approximately 50% of patients; abdominal
pain and hematuria are common
clinical symptoms. Polycythemia, a
characteristic finding seen in
approximately 10% of patients with
metanephric adenoma, promptly
disappears after surgical resection.
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Metanephric adenoma is histologically
characterized by the arrangement of
monotonous small blue embryonal epithelial
cells in an acinar, tubular, or sheetlike
configuration. Abundant psammoma bodies are
Metanephric adenoma typically appears as a
well-defined, unencapsulated, solitary solid
mass. It commonly appears as a
hyperattenuating mass on unenhanced CT;
large tumors appear as
heterogeneous, hypovascular masses with
frequent foci of hemorrhage and
necrosis. Calcification is seen in 20% of cases.
Metanephric adenoma appears as an expansile
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Angiomyolipoma (AML) is the most common benign
mesenchymal neoplasm; it is composed of variable
proportions of blood vessels, smooth muscle, and adipose
tissue. Renal AMLs consist of two distinct histologic subtypes,
classic triphasic and monotypic epithelioid. It will not be
further discussed in this article.Classic AML may occur either
sporadically or in association with tuberous sclerosis complex
(TSC). Sporadic renal AMLs show a 4:1 female preponderance
and are more likely to be solitary and symptomatic. Patients
with TSC harbor small, multicentric, asymptomatic AMLs;
80% of patients with severe TSC have renal AMLs. The
morphology of AMLs depends on the relative proportionsof
various components. Profuse elastin-poor, dysmorphic
blood vessels predispose to aneurysm formation and
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Renal hemangioma is a rare benign mesenchymal neoplasm
that consists of multiple endothelium-lined, blood-filled
vascular spaces. It commonly affects young adults with no
specific sex predilection. Recurrent episodes of hematuria and
renal colic are typical presenting symptoms; however, incidental
diagnosis in asymptomatic patients is also common.
Hemangioma of the kidney occurs as an unencapsulated,
unicentric, solitary tumor that frequently arises from the renal
pyramids or the pelvis.
Lymphangioma of the kidney is a rare benign cystic tumor
that most often arises from the peripelvic region or renal
sinus. It may also uncommonly arise from the lymphatics of the
capsule or the cortex. Histologically, lymphangiomas consist
of communicating endothelium-lined spaces that contain clear
fluid. The septa may show lymphoid cells.
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Mixed epithelial and mesenchymal neoplasms comprise two
histologically distinct entities: mixed epithelial and stromal tumors and
Mixed Epithelial and Stromal Tumor:
Mixed epithelial and stromal tumors occur almost exclusively in
perimenopausal women (6:1 female preponderance); most patients are
receiving estrogen therapy. Twenty-five percent of the tumors present as
incidental findings; most patients manifest nonspecific symptoms of flank
pain and hematuria. Pathologically, mixed epithelial and stromal tumor is
a benign, bimorphic solid-cystic neoplasm that consists of epithelium-
lined cysts or microcysts and variably cellular spindle-cell, ovarianlike
(estrogen- or progester-one-receptor positive) stroma.
Cystic nephroma is a benign cystic neoplasm that affects predominantly
middle-aged, perimenopausal women. Adult-onset cystic nephroma is
histogenetically and morphologically different from pediatric cystic
nephroma. Morphologically, cystic nephromas are composed
of encapsulated, noncommunicating cysts with thin septations.
Mixed Epithelial and Mesenchymal
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It is the most common primary renal tumor of
Age Incidence: 2-5 years.
Involve both kidneys either simultaneously or one
Pathogenesis and genetics:
There is association of at list three congenital
malformations with distinct chromosomal loci.
WAGR Syndrome: aniridia, genital anomalies, mental
retardation, and wilms tumor.
Denys-Drash Syndrome: gonadal dysgenesis,
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The tumor is large solitary well circumscribed mass
either bilateral or multi centric.
On cut section it is soft, homogenous, with
hemorrhage and necrosis.
On M/E: There is combination of blastemal,
stromal, and epithelial cell types.
Other heterogonous elements- Squamous or
mucinous epithelial adipose tissue and smooth
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Renal Cell Carcinoma
Renal cell carcinoma is the most common
primary parenchymal malignancy of the
kidney and accounts for 3% of all new
cancers annually in the United States, with
approximately 30,000 new cases per year.
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Histopathology of Renal Cell Adenocarcinoma, Kidney
6 October 2010 23
Renal Cell Cancer Risk Factors
Smoking: Cigarette smokers are twice as likely as
nonsmokers to develop kidney cancer.
Obesity: People who are obese have an increased risk
of kidney cancer.
High blood pressure: Increases the risk of kidney
Long-term Dialysis: Being on dialysis for many years
is a risk factor for kidney cancer.
Von Hippel-Lindau Syndrome: VHL is a rare disease
that runs in some families. An abnormal VHL gene
increases the risk of kidney cancer.
Occupation: Coke oven workers in the iron and steel
industry are at risk. Workers exposed to asbestos or
cadmiumalso may be at risk.
Gender: Males are more likely than females to be
diagnosed with kidney cancer.
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Renal Cell Cancer Symptoms
Blood in the urine (making the urine slightly rusty
to deep red)
Pain in the side that does not go away
A lump or mass in the side or the abdomen
Weight loss, fever, anemia
Feeling very tired or having a general feeling of
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Background and statistics
In the United States, kidney cancer accounts for about 3% of all
cancers, with approximately 12,000 kidney cancer deaths each
Kidney cancer strikes more than 28,000 Americans each year—
many of whom have no overt symptoms.
The majority of people with kidney cancer are past the age of
40, and it strikes men twice as often as women. Kidney cancer is
usually diagnosed between the ages of 50 and 70, but can occur
at any age.
It is one of the fastest-growing cancers in the United Kingdom.
There are several genetic factors that predispose people to
kidney cancer but this only happens in 5% of the cases.
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Classification Of Renal Cell Carcinoma
Clear Cell Carcinoma: 70% to 80% of renal cell
cancers on histology. The tumors are made of
cells clear or granular cytoplasm and are non-
They are associated with VHL disease. There
is loss of sequence on the short arm of
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10% to 15% of renal cancer
Papillary growth pattern occurs in both sporadic
and familial form.
Cryptogenic abnormalities- Trisomy 7,16,17, loss of
M/E: Complex Papillary formation are seen often
associated with prominent stromal infiltration by
neutrophils or foamy macrophages. Psammoma
bodies are numerous.
Immunohistochemistry- Expression of keratin.
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Cromophobe Renal Carcinoma:
5% of renal cell cancer.
On cytogenetic examination these
tumors exhibit multiple chromosome
losses. The cells are composed with
prominent cell membrane and pale
eosonophilic cytoplasm with a halo
around the nucleus.
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Collecting duct Carcinoma:
1% of renal epithelial carcinoma.
Arise from collecting duct cells of medulla.
A number of chromosomal losses and
Histologically nests of malignant cells
enmeshed within a prominent fibrotic
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Morphology of RCC:
The tumor may arise in any portion of kidney,
but usually affects the upper pole.
Clear cell neoplasm arise from proximal
They are spherical masses which may distort
the renal out line.
The margins are sharply defined.
In CCC the tumors cells have a rounded or
polygonal shape and abundant clear or
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Papillary tumors arise form distal convoluted
They are typically hemorrhagic and cystic.
As tumor enlarge they may bulge into the
calyces and pelvis and may extend into the
This tumor may invade the renal vein then to
the inferior vena cava and even in the right
side of heart.
The tumor composed of cuboidal or low
columnar cells arranged in papillary
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Characteristics: Its tendency to metastasize
before Clinical Sign/Symptom.
Common site of Metastasis:
Regional Lymph nodes, Liver, Adrenals and
6 October 2010 33
Surgery is the standard treatment for
contained kidney cancer. Various surgical
options may be available to you, depending on
tumor size and location within the kidney
capsule. Such surgery is performed by a
Radiation and chemotherapy are not very
effective in treating kidney cancer. Biologic
therapies are used more frequently.
6 October 2010 34
Urothelial Carcinoma of the Renal Pelvis:
Benign papillomas, Invasive TCC.
Urolethelial tumors may be multiple involving
the pelvis, ureter and bladder.
They may block the urinary out flow and lead to
hydronephrosis and flank pain.
5 year survival rate.
6 October 2010 35
Clear Cell Carcinoma
Contrast-enhanced CT image
during renal parenchymal
phase shows a right renal mass
with a mixed enhancement
pattern containing enhancing
solid soft tissue and low-
attenuation areas that may
represent cystic or necrotic
Contrast-enhanced CT image
during renal parenchymal
phase shows a left renal mass
with a mixed enhancement
pattern with a greater amount
of solid components
6 October 2010 36
Oncocytomas may overlap, however,
with clear cell RCC in terms of imaging
features and degree of enhancement.
On CT scans, the diagnosis of
oncocytoma may be suggested if a central
stellate scar is identified within an
otherwise homogeneous tumor.
6 October 2010 37
with left renal
CT image during
phase shows a left
renal mass with
enhancement and a
6 October 2010 38
Solid Renal Tumors- Papillary RCC
Papillary RCCs are typically
less vascular compared with
most other types of renal
tumors and most commonly
manifested as homogeneous
or peripheral enhancement.
A58-year-old man with a 15-
cm papillary RCC arising
from the right kidney.
Contrast-enhanced CT image
during renal parenchymal
phase shows a right renal
mass with mild
enhancementof 35 HU in
peripherally distributed soft
tissue. No enhancement is
identified in the central low-
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Cystic Renal Cell Tumors
(A)A 68-year-old woman
with breast cancer. T2-
weighted FSE MRimage
shows a complex cystic mass
in the left kidney, which was
proved to be a multilocular
cystic nephroma on
(B) A 52-year-old woman
with multilocular cystic RCC
in the left kidney. Contrast-
enhanced CT image at renal
parenchymal phase shows a
cystic mass containing
several thickened enhancing
septations in the left kidney
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77-year-old woman with a
malignant left renal
cortical tumor showing
(A) Axial fat-suppressed
T1-weighted image shows a
left renal mass (short
arrow) with tumor
thrombus extending into
the left renal vein (long
(B and C) Axial and
single-shot fast spin-echo
sequences show marked
expansion of the inferior
6 October 2010 41
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