<B>Cystic_Renal_Dysplasia </B>

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Cystic_Renal_Dysplasia

Etiology:

• This is a developmental disorder in metanephric differentiation.
• It occurs sporadically and is not genetic.
• Many cases have an associated lower tract obstructive lesion such as uretero-pelvic junction stenosis or occlusion, urethral valve or urethral atresia.

Pathogenesis:

• This is a developmental disorder in metanephric differentiation.
• Many cases have an associated lower tract obstructive lesion such as uretero-pelvic junction stenosis or occlusion, urethral valve or urethral atresia.
• There is belief that the obstructive lesion is primary and this affects the normal differentiation of the renal parenchyma.

Epidemiology:

• Cystic renal dysplasia is the most common form of cystic disease seen in the neonate.

General Gross Description:

• The cystic maldevelopment may be segmental and involve only portion of a kidney, or it may involve the whole kidney or both kidneys.
• Although not conspicuous because of the cysts, the solid intervening parenchyma is also part of the maldevelopment.
• The associated collecting structures (calyx, pelvis, ureter, bladder and urethra) may be atretic or obstructed.

General Microscopic Description:

• The histology of kidney shows multiple cysts of varying sizes lined by flat to cuboidal to columnar epithelium. The stroma around cysts may show concentric collars of mesenchymal cells. Islands of cartilage can sometimes be seen.

Clinical Correlations:

• Clinical manifestation of the disease will be dependent on the extent of renal parenchymal involvement and the obstructive lesions of the lower urinary tract if present.
• Limited segmental disease may go undetected and be asymptomatic.
• Bilateral diffuse involvement of the renal parenchyma would be fatal in the newborn.

References:
•Robbins Pathologic Basis of Disease, 5th Edition (Cotran, Kumar, Robbins editors) pp. 934-935. •Fetal and Neonatal Pathology, Keeling JW editor, 1987, Springer-Verlag publishers, pp. 412-414.