Renal Pathology:

Describe the Bosniak Staging of Renal Cysts

Bosniak I: simple cyst - uncomplicated, homogenous, benign

Bosniak IIF: likely benign, but with radiographic findings of: septations OR minimal calcification in wall or septum OR suspect of infection OR hyperdense. Risk of Malignancy 0-5%

Bosniak III: complex cyst, suspicious for malignancy. Radiographic findings include: irregular wall, thickened septa, and thick irregular calcification. Risk of Malignancy 50%

Bosniak IV: Likely cystic renal cell carcinoma. Radiographically, large cystic components, irregular, shaggy margins, and, most important, some solid enhancing portions. Risk of Malignancy 75-90%.

Renal Pathology:

What is the managment option for Bosniak I-IV?

Bosniak I: surveillence not necessary
Bosniak IIF: regular surveillence

Bosniak III: surgical excision
Bosniak IV: surgical excision

Renal Pathology:

Are benign renal cysts more common in Men or Women?

What percentage of individuals over age 50 have benign renal cysts?

Men:Women = 2:1

5% of people over age 50 have benign renal cysts

Renal Pathology:

Renal Cell Carcinoma

What are the types of RCC, what percentage of RCC do they make up, what genetic mutations are they asssociated with?

Clear Cell: 60-75% of RCC. Point mutation or allelic loss of VHL gene (maps to 3p). Also, these are bilateral in 1-2% of cases.

Papillary: 5-15% of RCC. Hereditary variant related to defect in c-met on 7q. Other genetic mutations include loss of Y-chromosome and trisomies of 7, 16 and 17. Not 3p (VHL)

Chromophobe: 5%. Variety of genetic mutations, but not 3p (VHL).

Renal Pathology:

Describe the epidemiology of Renal neoplasms.

(ie, which sex, age at presentation, racial distribution)

Gender: M > W by 2:1

Age at presentation: 5th to 7th decade of life

Racial: equal distribution (although greatest rates in Scandinavia, lowest in Asia)

Higher incidence in urban settings

Renal Pathology:

Risk factors for renal neoplasm

Smoking (2x relative risk)

HTN

Obesity

Acquired renal cystic disease in 4-9% of renal dialysis patients

Industrial Exposure NOT a risk

Renal Pathology:

Oncocytomas

What percentage of renal parenchymal neoplasms?

How often Bilateral?

Genetic Mutations?

Genetic Syndromes that are associated?

Benign or Malignant?

5% of renal parenchymal neoplasms

Bilateral 5% of the time

Translocation of chromosome 14, and mutations in mitochondrial DNA

Birt-Hogg-Dube: syndrome of bilateral oncocytomas or chromophobe RCC, as well as cutaneous lesions (fibrofolliculomas, acrochordones, trichodiscomas). Also associated with spontaneous pneumothorax.

Benign

Renal Pathology:

Angiomyolipoma

What is this also known as?

What is the gender distribution?

What genetic syndrome are they associated with?

How can they present?

AKA: renal hamartoma

W:M = 4:1

Tuberous sclerosis complex: condition of AD inheritence, associated with seizures, mental retardation, and adenoma sebaceum.

These can present as incidentalomas, OR as acute flank pain or shock due to spontaneous renal or retroperitoneal hemorrhage.

Renal Pathology

Sarcoma

Gender distribution?

Treatment of choice?

W>M

Radical nephrectomy. These are difficult to differentiate from RCC, and chemotherapy does not improve survival.

Renal Pathology

Metastasis to the kidney

What are the most common malignancies to go to the kidneys?

Lung, breast, uterus. Melanoma can as well.

Biopsy of the renal mass may be warranted in patients with signs of progression from their secondary malignancy.

Renal Pathology

Xanthogranulomatous pyelonephritis (XGP)

What is this? Gender distribution? Risk Factors? Treatment?

This is a rare renal infection that can mimic a renal tumor. Usually infection with E. coli or Proteus mirabilis is present, with obstructing renal calculi. Cells are lipid-laden macrophages that resemble clear cell RCC.

More common in women (3:1) in 5th-7th decades of life.

Diabetes mellitus in 15% of patients.

The best treatment is often nephrectomy as oppsosed to I&D.

Renal Pathology

Describe tumor staging for RCC

T0: no evidence primary tumor

T1a: Tumor <4cm

T1b: Tumor 4-7cm

T2: Tumor >7cm

T3a: extension from renal capsule

T3b: tumor extension into renal veins/IVC below diaphragm

T3c: tumor extension into IVC above diaphragm

T4: Tumor invades beyond Gerota's fascia

Renal Pathology

What paraneoplastic syndromes are associated with RCC?

• hypercalcemia 2/2 parathyroid-like hormone production (5%), or 2/2 metastatic bone destruction
• Stauffer's syndrome (14%): LFT abnormalities with hepatomegaly that resolve (in 88% of patients) with excision of RCC
• amyloidosis (2%)
• thrombocytosis
• protein-wasting enteropathy
• erythrocytosis