Urinary Tract Pathology Case Studies


CASE 1: Recessive Polycystic Kidney Disease (RPKD)


Clinical History:

This was a 27 week gestational age stillborn. Severe oligohydramnios was present. A fetal ultrasound was difficult to interpret because of the lack of amniotic fluid, but enlarged, cystic kidneys were thought to be present. At autopsy, the kidneys were symmetrically enlarged and on sectioning displayed numerous 0.1 to 0.2 cm cysts. Other findings included pulmonary hypoplasia, prominent infraorbital creases with flattened nose on the face, and varus deformities of both feet.
  1. What is the diagnosis?

    2. This is recessive polycystic kidney disease (RPKD), also known as infantile polycystic kidney disease.

  2. What are the consequences of this disease?

    3. Renal failure develops. Those infants who survive for a while may develop congenital hepatic fibrosis along with cysts in the liver. The disease is essentially uniformly fatal.

  3. How would you counsel the family regarding the recurrence risk for this disease?

    4. Since it is recessive (image 1.4), there is a 25% recurrence risk.

  4. How does this case differ from the other forms of cystic disease of the kidney?

    5. Dominant polycystic kidney disease (DPKD) has an autosomal dominant pattern of inheritance (image 1.6), compared to autosomal recessive for the infantile form. The disease is usually manifested in adults in middle or old age. The kidneys are massively enlarged with huge cysts, seen in image 1.5.

    Multicystic dysplastic kidneys are seen in fetuses and infants sporadically with no specific pattern of inheritance, though some cases are part of syndromes, such as the Meckel-Gruber syndrome. The cysts are variably sized, and the kidneys are typically asymmetric (images 1.7 and 1.8). The term "dysplasia" here means that the development is disordered, with few glomeruli and tubules and with an irregular primitive stroma, sometimes containing cartilage (image 1.9). This form of cystic renal disease is much more common than either RPKD or DPKD. (Compare with normal kidney, images 1.10 and 1.11).