Renal Mass | Medical Science Optional Notes for UPSC PDF Download

Wilm's tumor

Wilms tumor, also called nephroblastoma, stands as the predominant primary malignant kidney tumor in children. It holds the position as the second most prevalent abdominal malignancy during childhood. Typically, this condition arises in children aged between 2 and 5 years old.

Gross Anatomy

Wilms tumor is typically a large, solitary, well-defined mass, although around 10% are either bilateral or multicentric upon diagnosis. On examination, the tumor appears soft, homogeneous, tan to gray, occasionally displaying hemorrhagic areas, cystic changes, and necrosis.

Histopathology

The classic Wilms tumor consists of varying proportions of blastemal, stromal, and epithelial cells, resembling different stages of normal kidney development.

Presentation

Children aged 2 to 5 years often present with symptoms such as palpable abdominal swelling, pain, hematuria, fever, and sometimes obstruction due to the tumor's size. Common sites of metastases include the lungs, regional lymph nodes, and liver.

Diagnosis

Laboratory studies recommended include CBC, kidney function tests, electrolyte measurements, urinalysis, coagulation studies, and cytogenetic studies (including lp and 16q deletion). Imaging studies confirm a solid kidney lesion, possibly with venous invasion, contralateral involvement, or distant spread. Imaging modalities include renal ultrasonography (often the initial study), chest X-rays, abdominal and chest CT scans, and abdominal MRI.

Medical Procedures

Treatment often involves nephrectomy and lymph node biopsy sampling for staging purposes.

Differential Diagnosis

Other conditions that might resemble Wilms tumor include renal cell carcinoma, clear cell sarcoma of the kidney, rhabdoid tumor of the kidney, nonmalignant masses, hydronephrosis, multicystic kidney disease, renal cysts, renal thrombosis, dysplastic kidney, and renal hemorrhage.

Staging

Children's Oncology Group employs staging criteria for Wilms tumors to classify and determine appropriate treatment protocols.

Children's Oncology Group staging of Wilms tumors

Treatment

• Wilms tumor treatment shows impressive success rates, with a positive prognosis overall. Combining nephrectomy (kidney removal) and chemotherapy yields excellent outcomes.
• Children diagnosed with loss of heterozygosity at genetic locations 1p and 16q undergo more intensive chemotherapy due to a poorer prognosis compared to those without this genetic loss.

Etiology

• These tumors represent 80% to 85% of all primary malignant tumors of the kidney and 2% to 3% of all cancers in adults
• Renal cell carcinomas are derived from the renal tubular epithelium (PCT) and hence they are located predominantly in the cortex.
• Carcinomas of the kidney are most common from the sixth to seventh decades, and men are affected about twice as commonly as women.

High Risk

• Age risk peaks in the sixth or seventh decade of life.
• There's a higher incidence among men compared to women at a ratio of 2 to 1.
• Increased risk factors include smoking, hypertension, obesity, exposure to cadmium, chronic kidney disease (risk amplifies by 30 times in those with polycystic disease), history of renal transplantation, undergoing hemodialysis, and having a family history (doubling the risk).

Classification based on histopathology

Major subtypes with >5% incidence are clear cell RCC (ccRCC), non clear cell RCC (papillary RCC (pRCC) and chromophobe RCC (chRCC)).

ccRCC is the most common subtype and accounts for the majority of deaths from kidney

Clinical features

• Frequently discovered by chance
• The traditional triad is observed in fewer than 10% of cases
• Paraneoplastic syndromes may manifest, including fever, polycythemia, hypercalcemia, hypertension, Cushing syndrome, or feminization/masculinization
• Varicocele occurs in 2% of males, typically on the left side, resulting from testicular vein obstruction
• Severe, piercing, belt-like back pain could serve as an early indicator of spinal cord compression from metastatic renal cell carcinoma

Differential diagnosis

• Presence of an abscess is accompanied by a high-grade fever
• Angiomyolipoma, a benign neoplasm, is linked to tuberous sclerosis, with CT and MRI revealing the presence of fat
• Kidney metastasis often arises from distant primary lesions, with melanomas and various solid tumors—such as lung, breast, stomach, gynecologic, intestinal, and pancreatic cancers—being the most common culprits
• Oncocytoma and renal adenoma are both benign neoplasms
• Other potential kidney conditions include renal cysts, renal infarction, and sarcoma
• Acute or chronic pyelonephritis may affect the kidneys
• Bladder cancer is among the possible related conditions
• Non-Hodgkin lymphoma (NHL) is also associated with kidney involvement
• Wilms tumor is another pathology that can affect the kidneys

Renal cell carcinoma

Investigations

• CBP (hematocrit raised)
• ESR raised
• Surgical profile 
• Serum calcium 
• CT imaging with contrast enhancement of the chest, abdomen and pelvis 
• MRI-if venous involvement is suspected (RCC permeate into IVC even up to right atrium) 
• Bone scan 
• FDG PET CT
• Cystoscopy and ureteroscopy to rule out urothelial carcinoma

Renal cell carcinoma-staging

• Stage I categorizes renal cell carcinoma based on a tumor size of less than 7 cm, confined solely within the kidney.
• Stage II involves tumors exceeding 7 cm but still restricted to the kidney.
• Stage III identifies tumors extending into major veins or the adrenal gland while maintaining the integrity of Gerota's fascia, or those involving regional lymph nodes.
• Stage IV designates tumors surpassing Gerota's fascia, indicating a more advanced and invasive stage of renal cell carcinoma.

Renal cell carcinoma-Treatment

• Partial Nephrectomy Goal: The objective is to eliminate the primary tumor while preserving the maximum possible healthy renal parenchyma.
• Alternatives to Open Partial Nephrectomy:
  • Laparoscopic Partial Nephrectomy (LPN) and Robot-Assisted Partial Nephrectomy (RAPN) serve as primary alternatives to the traditional Open Partial Nephrectomy (OPN).
• Indications for Partial Nephrectomy: 
  a. Tumors smaller than 7 cm in the greatest dimension, confined to the kidney with a normal contralateral kidney.
  b. Patients with a single kidney.
  c. Von Hippel-Lindau (VHL) syndrome.
• Complications:
  • Hematuria
  • Perirenal hematoma
  • Urinary fistula
  • Acute renal impairment
  • Infection
• Radical Nephrectomy/Cytoreductive Nephrectomy:
  • Involves removal of the kidney, perirenal fat, adrenal gland, and regional lymph nodes.
  • Laparoscopic procedures can be employed for tumors limited to the kidney (Stage I and II).
• In Case of IVC Thrombus:
  • Removal is performed using cardiopulmonary bypass techniques.
• Active Surveillance and Ablative Therapies:
  • Suitable for patients unfit for surgery, such as elderly patients with limited life expectancy.
  • Radiofrequency ablation or cryotherapy, conducted laparoscopically or percutaneously under CT or ultrasound guidance, is an option with a higher local recurrence rate.
• Medical Management with Targeted Therapies:
  • In cases of metastasis, renal cell carcinoma (RCC) is highly vascular.
  • VEGF inhibitors (e.g., Sorafenib, Sunitinib, Pazopanib, Axitinib, Lenvatinib, Cabozantinib).
  • Anti-VEGF monoclonal antibody (Bevacizumab).
  • mTOR inhibitors (Everolimus and Temsirolimus).
  • The average duration of disease control with these agents is approximately 8-9 months.

Renal Mass-Repeats

Q1: Discuss treatment of a child with Wilm's Tumour. (1997) 

Q2: A 50-year-old male presented with a history of hematuria and dragging discomfort in the left loin. On abdominal examination, it was found that he has Lt sided renal lump with Lt Varicocele. (2016)
(i) Discuss the differential diagnosis and investigation of the above mentioned condition
(ii) Mention the treatment of left-sided renal cell carcinoma.