MUSTAFA SA'EB
Adenocarcinoma of the kidney (Renal Cell Carcinoma RCC, Clear cell carcinoma,
hypernephroma )
It accounts for about 3% of adult cancers and
constitutes
approximately 85% of all
primary malignant renal tumors .It occurs most commonly in fifth to sixth decade of life
and has male – female ratio of 2 : 1 , regarding the race it is more common in black than
in white peoples .
Etiology
The cause of RCC is unknown, but there is numerous risk factors: -
1- Occupational exposure (asbestos, solvents, cadmium).
2- Chromosomal aberrations.
3- Tumor suppressor genes.
4- Cigarette smoking.
5- Acquired cystic renal disease.
Pathology
RCC originates from the proximal renal tubular epithelium . these tumors occurs with
equal frequency in the either kidney and are randomly distributed in the upper and lower
poles , it originates in the cortex and tend to grow out into the perinephric tissue causing
the characteristic bulge or mass effect that aids in their detection by diagnostic imaging
studies , grossly RCC is yellow or orange because the abundance of lipids particularly in
the clear cell type , it has no true capsule but may have pseudo capsule of compressed
renal parenchyma ,
Pathogenesis
RCCs are vascular tumors that tend to spread either by direct invasion through the renal
capsule into the perinephric fat and adjacent visceral structures or by direct extension
into the renal vein, approximately 25-% of patients have evidence of metastasis at
presentation, the most common sites of distant metastases is the lung, liver, bone,
ipsilateral adjacent lymph nodes and adrenal glands.
Tumor staging
The goal of staging is to select appropriate therapy and obtain prognostic information,
The TNM classification system is used for staging of RCC: -
T -----------primary tumor
T1 tumor 7 cm or less limited to the kidney.
T2 tumor more than 7 cm limited to the kidney.
T3 tumor extends into major veins or invades adrenal gland or perinephric tissues
but not beyond g Gerotas fascia
T4 tumor invades beyond Gerotas fascia.
N ----Regional lymph nodes
N0 No regional lymph node metastasis.
N1 metastasis in a single regional lymph node.
N2 metastasis in more than a single regional lymph node.
M- Distant metastasis
M0 No distant metastasis .
M1 distant metastasis .
Clinical findings
The classical triad of gross hematuria , flank pain and palpable mass occur in 10%of
patients and is a manifestation of advanced disease , dyspnoea , cough , and bone pain are
symptoms of secondary metastasis , with use of CT Scan now more than 50% of the cases
of RCC are detected incidentally .
Paraneoplastic syndromes
RCC is associated with a wide spectrum of paraneoplastic syndromes, these
manifestations can occur in 20% of patients with RCC including: -
1- Erythrocytosis because of overproduction of erythropoietin from the neoplastic or
nonneoplastic renal tissue ) .
2- Hypercalcemia can occur in 20% of patients with RCC due to production of
parathyroid hormone-related .
3- Hypertention can occure in 40% of patients with RCC due to rennin production by
the tumor .
4- Nonmetastatic hepatic dysfunction can be seen in 15% of the cases and is called
Staufler's syndrome and it is reversible including elevation of alkaline phosphatase ,
billirubin , hypoalbunemia , prolonged prothrombin time and hypergamaglulinemia
.
Laboratory findings
Anemia, heamaturia , elevated ESR , these findings are nonspecific and normal
findings do not rule out diagnosis of RCC .
Imaging
The most sensitive imaging technique for accurate diagnosis of RCC is CT Scan , U/ S ,
MRI , renal arteriography , IVU , Radionuclide imaging are helpful. .
Differential Diagnosis
1- Other solid renal lesions (Benign renal masses like granulomas and arteriovenous
malformations, Renal lymphomas both Hodgkin's and non Hodgkin’s, Transitional
cell carcinoma of the renal pelvis, Adrenal cancers, Metastatic disease ) .
2- Renal cysts.
Treatment
1- Localised disease surgery (radical nephrectomy ) is the treatment of choice .
2- Disseminated disease Approximately 30% of patints with RCC will present with
advanced disease treatment may vary from debulking surgery to radiotherapy and
biologic response modifier agents (Interferone alpha IFN- and interluleukin-2 IL-2).
Prognosis
Depends on the stage of the disease at presentation , 5 year survival rates for patients with
T1-T2 may reach 80-100% , For T3 50%.
Wilms Tumor (Nephroblastoma )
Is the most common solid renal tumor of childhood, accounting for about 5% of
childhood cancers, , the peak age of presentation is during the third year of life , and there
is no sex predilection . in about 5% of the cases the tumors are bilateral .
Etiology
Mutation in the sort arm of the chromosome 11 (11p13) (WT1) have been recognized in
cases of familial wilms tumor, whereas only 10% of patients with sporadic (non familial)
have WT1 mutation.
Pathology and Pathogenesis
Wilms tumor precursor lesions are found and known as nephrogenic rests (NR), some NR
remain dormant for many years and undergoing involutions and sclerosis and others are
giving rise to Wilms tumor. the Wilms tumor can be classified in to favorable and non
favorable histological types , in the non favorable type the tumor contains focal or diffuse
elements of anaplastic cells. Favorable Wilms tumor is without anaplasia .
Tumor dissemination can occur by direct extension through the renal capsule ,
heamatogenousely via the renal and vena cava or via lymphatic spread , metastatic disease
is present in 15% of patients at time of diagnosis , with the lungs 90% and liver 15% the
most common sites , regional lymphatics in about 25% of the cases .
Staging
The National Wilms Tumor Study (NWTS ) staging system is most widely used
Stage I: -Tumor limited to the kidney and completely excised , no penetration of the renal
capsule or involvement of renal sinus vessels .
Stage II: - tumor extends beyond the kidney but is completely removed. No residual tumor
at or beyond the resection margins and no lymph node involvement.
Stage III: The tumor can not be completely excised and the tumor extends beyond the
surgical margins, regional lymph node involvement present, peritoneal contamination and
implantations.
Stage IV: - Heamatogenous metastasis to the lung, liver, bone and brain.
Stage V: - Bilateral renal involvement at diagnosis.
Clinical findings
Symptoms and signs
The diagnosis of Wilms tumor is made after discovery of an asymptomatic mass by a
family member or a physician during a routine physical examination, common symptoms
at presentation include abdominal pain and distention, anorexia nausea and vomiting,
fever and heamaturia . The most common sign is an abdominal mass; hypertension is seen
in 25%, heamaturia in 30%
Laboratory findings
GUE may show heamatiria, blood analysis may show anemia , abnormal liver function
tests .
X-Ray findings
Abdominal U /S and CT scan are performed initially for evaluation of the mass, CT scan
is very useful in evaluation of the tumor extension, the status of the contralateral kidney
and the presence of regional lymph node and distant metastasis, chest X-Ray is helpful for
detection of lung metastasis.
Needle Biopsy
Is needed in cases of very large mass which can not be removed by safe surgery for which
preoperative (neo adjuvant) chemo or radiotherapy is planned.
Differential Diagnosis
Hydronephrosis , cystic kidney , intrarenal neuroblastomas , mesoblastic nephroma and
rarely sarcoma .
Treatment
Patients with unilateral mass which is respectable surgery is the treatment of choice.
Wilms tumor is a chemo sensitive neoplasm and chemotherapy is very useful both pre
and postoperatively, it is also radiosensitive and
radiotherapy is also very important but since patients with Wilms tumor is very young
and still their body organs is growing so it's use is limited .
Prognosis
The 4 year survival of patients with favorable histology is up to 90%, the most important
negative prognostic factors is the non favorable histological subtypes (clear cell sarcoma,
rhabdoid and anaplastic tumors).