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| Adult Polycystic Kidney Disease |
| Etiology •Genetic, autosomal dominant with high penetrance. •At least two different genes can produce the disease, one being located on the short arm of chromosome 16 (APKD1). |
| Pathogenesis •The basic pathologic process may be considered a proliferative/hyperplastic abnormality of the tubular epithelium. •In the early stages of cyst development, the cysts are connected to the tubules from which they arise and the fluid content is glomerular filtrate. •When the cyst diameter exceeds 2 mm, most detach from the patent tubule and the fluid content is derived from secretions of the actual lining epithelium. •With time, the cysts enlarge and cause progressive damage to adjacent functioning nephrons. •Cysts develop along the entire length of the nephron., |
| Epidemiology •Relatively common, occurring in one in 500 to 1000 individuals. •Adult PKD is the third most common cause of end-stage renal disease. |
| General Gross Description •The disease is bilateral. •The kidneys are enlarged (can be massive, up to 4 kg each). •The kidneys overall remain reniform in shape but the parenchyma shows innumerable cysts of varying sizes from barely visible to 4 to 5 cm. •The cysts show a variety of colors due to the fluid content which may be clear to reddish brown. •Cyst development is found in both cortical and medullary regions. |
| General Microscopic Description •Most of the cysts are lined by non-descript, flattened to cuboidal epithelial cells. •Some cysts however show epithelia with features of proximal tubules, distal tubules and collecting ducts. •Tissues between the cysts may show unremarkable or atrophic nephron elements. |
| Clinical Correlation •The patients usually present in the fourth to fifth decade of life with progressive renal insufficiency and bilaterally enlarged cystic kidneys. •Hypertension is a common complication, perhaps on the basis of cysts causing local ischemia. •Although the cystic disease may be ultrasonographically detected in infants, children and young adults, 11 to 17% of patients with adult polycystic kidney disease type I (chromosome 16 defect) have normal ultrasound before age 30. •Extrarenal manifestations include: hepatic, pancreatic and splenic cysts; intracranial and aortic aneurysms; and cardiac valve abnormalities. |
| References • Cotran RS, Kumar V, Robbins SL: Robbins Pathologic Basis of Disease. 5th ed. Philadelphia, W.B. Saunders, 1994, pp. 935-936. •Primer on Kidney Diseases, Greenberg A (editor), National Kidney Foundation 1994. pp.201-206. |
| Adult Polycystic Kidney Disease |
| Synopsis by: Harold Yamase M.D. (T71000M26730)[222] |
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