Table 3.

Differential diagnosis of other kidney cystic diseases

Disorder	Inheritance	Family History	Clinical features
Multiple benign simple cysts	Acquired	none	Relatively common in the general population; increase in number and size with age (age< 30, Uncommon, rarely multiple or bilateral; age 30-59, Uncommon to have at least 2 cysts in each kidney; age > 60, Uncommon to have ≥ 4 cysts in each kidney); kidney ultrasound in family members may be helpful
Acquired kidney cystic disease	Acquired	none	Seen in advanced CKD, particularly in patients receiving RRT; Cysts are small, bilateral and multiple (>4 cysts in each kidney); Kidneys are small to normal in size.
Localized kidney cystic disease	Acquired	None	Uncommon, benign, unilateral, not progressive
Autosomal recessive polycystic kidney disease (ARPKD)	Autosomal recessive	25% concordance between siblings	Affects ~1 in 20,000; in neonates, death in 30%, enlarged echogenic kidneys and pulmonary hypoplasia; in older children, biliary dysgenesis (congenital hepatic fibrosis, intrahepatic bile duct dilatation) resulting in portal hypertension and cholangitis; collecting duct ectasia and macrocystic changes associated with calcifications, hypertension, and/or decrease in kidney function
Tuberous sclerosis complex (TSC)	Autosomal dominant	Absent in 2/3 of cases	Affects ~1 in 10,000 live births; skin lesions (facial angiofibromas, periungual fibroma, hypomelanotic macules, shagreen patch); >90% have cerebral pathology (cortical tuber, subependymal nodules, giant cell astrocytoma); 90% have kidney manifestations (polycystic kidneys, angiomyolipomas); 50-70% have retinal hamartomas; 50% have pulmonary lymphangioleiomyomatosis
PKD1-TSC contiguous gene syndrome	Autosomal dominant	Spontaneous presentation frequent	Presentation with polycystic kidneys at an early age, with kidney angiomyolipomas frequently presenting after the first year of life
von Hippel-Lindau syndrome	Autosomal dominant	~ 20% de novo	Affects ~1 in 36,000; Cerebellar and spinal hemangioblastoma; retinal angiomas; serous cystadenomas and neuroendocrine tumors of pancreas; pheochromocytoma; renal cell carcinoma
Medullary sponge kidney (MSK)	Unclear; autosomal dominant in some cases	Familial clustering reported	Affects ~1 in 5000; tubular dilatation of the collecting ducts giving the appearance of “brush” or linear striations on intravenous pyelogram; medullary nephrocalcinosis; kidney stones; kidney cortex spared on CT scans or MRI
Medullary cystic kidney disease (MCKD**)	Autosomal dominant	rare	Slowly progressive kidney disease; medullary cysts (but uncommon in families with type 2 MCKD**); hyperuricemia and gout (in type 2 MCKD**); small to normal sized kidneys.
Renal cysts and diabetes syndrome (RCAD/MODY5/HNF-1B*)	Autosomal dominant	Spontaneous mutations (often deletions) in 50%	Kidney cysts or malformation in 90%, diabetes mellitus in 45%, hypomagnesemia in 40%, genital tract abnormalities in 20%, hyperuricemia in 20%, elevated liver enzymes in 15%
Bilateral parapelvic cysts	Unknown		Lymphatic (not epithelial) cysts; distort the kidney pelvis, infundibula, and calyces

Abbreviations: ADTKD, autosomal dominant tubulointerstitial kidney disease; ESRD, end-stage renal failure; MODY5, maturity onset diabetes mellitus of the young type 5; PKD1, polycystic kidney disease 1; CKD, chronic kidney disease; RRT, renal replacement therapy; CT, computed tomography; MRI, magnetic resonance imaging; MUC1, tumor-associated mucin; UMOD, uromodulin; HNF-1B, hepatocyte nuclear factor 1β;

^*Current designation is ADTKD-HNF1B

^**Use of the term MCKD is discouraged; what was formerly type 1 MCKD should be referred as ADTKD-MUC1 and what was formerly type 2 MCKD should be referred as ADTKD-UMOD.