Congenital anomalies

Know the possible mechanisms of renal agenesis

• Failure of Wolffian duct to make contact w/ mesodermal mass

• Complete absence of nephrogenic primordium

Know the criteria for the diagnosis of hypoplastic kidney

• Reduced number of renal lobules and calyces (<>)

Know the complications of ectopic kidneys

• Kinking and tortuosity of ureters predisposes to bacterial infections and stones

Know that the majority of horseshoe kidney fusions occur at the lower pole

• 90 % to be exact

Know the possible complications of horseshoe kidney

• Slight increase in incidence of stones

• Due to position of kidney anterior to great vessels, compression can cause HTN

Know the gross and microscopic features of renal dysplasia and that renal dysplasia is usually associated with urinary tract anomaly. Is the disease hereditary?

• Kidney enlarged with cysts of varying sizes lined by flat epithelium

• Presence of cartilage, undifferentiated mesenchyme, and immature collecting ductules

• Does NOT show any familial hereditary pattern, but is associated with syndromes such as Prune Belly syndrome

Know the possible pathogenesis of renal cyst formation: Abnormality in cell differentiation, proliferation, and fluid secretion.

Know the incidence of ADPKD and the location and frequency of genes responsible for ADPKD

• Incidence is 1:1000 (most common genetic disorder in humans)

• Autosomal dominance means that at least 50% of offspring of an affected parent will inherit the defective gene

• The most common defective gene is located on p16

Know the age of onset of clinical manifestations and causes of death in patients w/ A(D)PKD

• Age of onset of clinical symptoms is usually 30s – 40s

• 40% die from coronary or hypertensive heart disease

• 25% from infection (probably augmented by azotemia from renal failure)

• 15% from ruptured Berry aneurysm

• Rarely, there are fatal cases in newborns (intrapartum dystocia or postnatal renal failure)

Know the diseases that are usually associated with ADPKD

• Liver cysts – not a major consequence

• Berry aneurysms

• Pancreatic, spleen, lung cysts

• Aortic and visceral aneurysms, aortic coarctation, cardiac valve abnormalities (e.g., mitral valve prolapse)

• Marfan’s syndrome

• Colon diverticulosis

• Renal cancer – occurs at younger age and at higher incidence of bilateral involvement than normal

Know the gross, micro, and origin of the cysts of ARPKD

• Gross pathology

• Enlarged, but retains normal shape and lobulations

• Subcapsular surface studded w/ innumerable small cysts

• Fusiform radiations extending from medulla  cortex

• Micro pathology

• Cysts arise from dilation of collecting tubules lined with cuboidal cells

• Cysts cause compression, resulting in glomerular obsolescence, tubular atrophy, and interstitial fibrosis

Which type of polycystic kidney disease is usually associated with hepatic fibrosis?

• ARPKD

Know the location of cysts, clinical presentation, and prognosis of medullary sponge kidney.

• Location - Intrapyramidal

• Clinical presentation

• Usually incidental diagnosis

• Can occur at any age

• Hematuria, stones, recurrent UTI

• Proteinuria in 50%

• Hyperuricemia, hypercalciuria

• Mild degree of salt wasting

• Distal tubular acidosis

Know the gene, location of cysts, and complications in acquired cystic disease

• No associated genes

• Cysts located in cortex and medulla due to obstruction

• Sometimes cysts bleed, causing hematuria

• Renal cell carcinoma occurs in cyst walls of 7% of dialysis patients

What is a simple cyst?

• Appear as spherical, tense, thin-walled cysts filled with what appears to be plasma ultrafiltrate

• They may single or multiple and can appear in the cortex or medulla

• They are found in 50% of patients over 50 at autopsy

• Important to rule out cystic adenocarcinoma

Category: Pathology Notes