Urology
Monday 11/12/2017
Renal Neoplasms
Renal tumors can be classified into benign and malignant. The malignant tumors are more common and more serious. They can be primary or secondary. Primary tumors can be further classified according to the site of origin in the kidney.
Benign Tumors:
Renal Adenoma: Usually asymptomatic discovered accidentally.
Renal Angioma: This tumor is benign. However it may produce profuse bleeding that can be localized only by using angiography. It may need embolization.
Renal Angiomyolipoma: This is a rare benign tumor that contains, as the name implies, blood vessels, smooth muscle fibers and fatty tissue. It is also called renal hamartoma. It is usually asymptomatic but may be associated with tuberous sclerosis. Sometimes bleeding may occur from the tumor and need intervention. Some tumors may contain malignant elements.
The presence of fatty tissue in this tumor makes its appearance in CT Scan diagnostic.
Treatment include surgical resection or embolization.
Other benign tumors include fibroma, lipoma, leiomyoma and juxtaglomerular tumor.
Malignant Tumors:
Wilm’s Tumor: (Nephroblastoma)This tumor usually contains elements from embryonic nephrogenic tissue. It is a rapidly growing, highly aggressive tumor. It is usually discovered in the first five years of life. Bilateral tumors may occur.
Clinical Features: The tumor is usually discovered by palpating an abdominal mass by the parents. The most common symptoms include abdominal pain and distension, anorexia, fever and hematuria (Which implies extension of the tumor to the renal pelvis). Hypertension may be found in some cases. Metastasis usually occurs early to the lung. Liver and bone metastasis are rare.
Laboratory Findings: There may be hematuria, anemia and disturbed liver function in cases of liver metastasis.
Imaging: A space-occupying abdominal mass can be seen by imaging techniques.
Treatment: The tumor is best treated by chemotherapy followed by nephrectomy. Partial nephrectomy may be feasible for bilateral cases.
Prognosis: The prognosis is good with long-term survival with the prompt use of chemotherapy and surgery. Poor prognostic factors include late presentation and metastatic disease.
Renal Neoplasms in Adults:
Renal Cell Carcinoma: (RCC / Adenocarcinoma / Grawitz Tumor / Hypernephroma)
It is the most common renal neoplasm. It arises from the renal tubular cells. The tumor is aggressive and has the tendency to spread locally to the renal vein. The malignant cells then pass to the circulation and reach the lung to form cannon ball metastasis. Metastasis may occur also to the bones especially long bones. Local spread may invade the lymphatics near the renal hilum creating another mode of metastasis.
Etiology: The exact cause is unknown. Familial predisposition is found in Von-Hippel-Lindau syndrome. Risk factors may include smoking and occupational exposure to Cadmium and leather. Acquired renal cystic disease and adult polycystic disease are also risk factors.
Pathology: The tumor arises from the proximal convoluted tubules. The cut surface of the tumor is yellowish with spots of bleeding and occasional central necrosis.
Clinical Features: The tumor is more common in males. It usually present with hematuria. It may also present with a dragging pain or a palpable mass. In males, a rapidly developing testicular varicocele may be found especially on the left side.
The tumor may present with features of metastasis or it may present with atypical presentation (Paraneoplastic Syndrome) which may include:
Hematologic disturbances: anemia, polycythemia and high ESR
Endocrine abnormalities: There may be hypercalcemia or rise in other hormones such as insulin, renin, erythropoietin, TSH and cortisol.
The tumor may be discovered accidentally.
Investigations: Laboratory investigations will reveal the above mentioned abnormalities.
Imaging is the mainstay in the diagnosis. CT scan and MRI has largely replaced IVU in the diagnosis. It will show the mass in the kidney in addition to local extension and any affected lymph nodes. A chest X-ray is important to detect lung metastasis and an isotope bone scan will show bone metastasis.
Treatment:
Radical surgical removal (Radical Nephrectomy) is the main stay of the treatment. It includes removal of the kidney with its perinephric tissue and Gerota’s fascia altogether.For metastatic tumor, other modalities of treatment are needed. Chemotherapy and radiotherapy are not quite effective. However, immunotherapy using interleukins and interferon are promising.
Prognosis:
Complete removal of the tumor may be curative. Local or distant spread is associated with a poor prognosis.
Transitional Cell Carcinoma of The Renal Pelvis:
This tumor is similar to transitional cell tumor of the bladder but it is less common. It arises from the urothelium in the renal pelvis and may invade the parenchyma. It may be multifocal and associated with multifocal tumor in the ureter and the bladder.
Predisposing factors include smoking and occupational exposure to chemicals like dyes and solvents. The tumor most commonly presents with hematuria or pain due to the obstructing effect of the mass. Malignant cells are shed in urine which aids in the diagnosis.
The diagnosis is made by finding malignant cells in the urine and by imaging. In IVU the tumor appears as a filling defect and CT or MRI will reveal the mass.
Treatment: is by radical nephroureterectomy. The kidney is removed together with the ureter and a cuff from the bladder.