This document provides a classification and overview of cystic diseases of the kidney. It discusses the main types of polycystic kidney diseases including autosomal recessive and dominant polycystic kidney disease. It also covers tubulointerstitial syndromes that can present with cysts, such as nephronophthisis and medullary cystic kidney disease. Cystic neoplasms and neoplastic cysts are described, including cystic nephroma and tubulocystic renal cell carcinoma. The pathogenesis, histopathology, and genetics of many of these conditions are summarized. Miscellaneous cysts like simple renal cysts and medullary sponge kidney are also briefly outlined.

1. CYSTIC DISEASES OF KIDNEY
Dr Anshita Dubey

2. CLASSIFICATION

5. Bonsib (2009) Classification of Renal Cystic Diseases and
Congenital Anomalies of the Kidney and Urinary Tract
I. Polycystic renal diseases
• Autosomal-recessive polycystic kidney disease
• Autosomal-dominant polycystic kidney disease
• Acquired renal cystic disease
• Glomerulocystic kidney diseases
III. Tubulointerstitial syndromes +/- cysts
A. Renal tubular dysgenesis
B. Nephronophthisis
C. Medullary cystic diseases
D. Bardet-Biedel syndromes

6. IV. Cystic neoplasms and neoplastic cysts
• Cystic nephroma
• Mixed epithelial and stromal tumor
• Multilocular cystic renal cell carcinoma
• Tubulocystic renal cell carcinoma
• Von Hippel–Lindau disease
• Lymphangioma/hygroma renalis
• Cystic partially differentiated nephroblastoma
V. Miscellaneous cysts
• Simple cortical cysts
• Medullary sponge kidney
• Localized renal cystic disease

7. PATHOGENESIS

9. Polycystic renal diseases

10. Autosomal recessive polycystic
kidney disease
• mutations of a gene on chromosome 6p named polycystic kidney hepatic disease
gene (PKHD1)
• related protein polyductin (fibrocystin) - epithelial cells of the collecting ducts,
thick ascending loops of Henle, biliary and pancreatic duct epithelia

11. • neonatal period - renal symptoms
• ‘Potter’ phenotype
• POTTER’S SEQUENCE
RENAL FAILURE
OLIGOHYDRAMINIOS
COMPRESSION AND STRUCTURAL ABNORMALITIES
PULMONARY HYPOPLASIA
• perinatal period – renal failure and
portal hypertension

12. • Later in life - congenital hepatic fibrosis with a biliary dysgenesis and bile duct
ectasia
• Hepatic portal hypertension with hepatosplenomegaly and esophageal varices
Gross-The cysts tend to be linear and radiate from
the medulla to the outer cortex. Develop in the
collecting ducts, which expand to a large size due to
fluid accumulation within the cyst cavity.
Microscopically- the cysts appear as dilated tubular
structures lined by cuboidal or flattened epithelium

13. Autosomal dominant polycystic
kidney disease
PKD1 and PKD2 located on chromosomes 16p and 4q
fourth and fifth decade; bilateral
flank pain, flank masses, hematuria, hypertension,
and renal failure
GROSS - bosselated outer cortical surface
Fluid-glomerular filtrte; Later- transepithelial secretn
Lm - lined by cuboidal, flattened epithelium;
interstitial scarring, tubular atrophy, and
pyelonephritis are common
Cerebral and coronary artery aneurysms, mitral valve
prolapse, abnormal aortic valves, colonic
diverticulae, and skeletal malformations

14. Acquired renal cystic disease
• Three or more cysts per kidney in patients on longstanding hemo- or peritoneal
dialysis for end stage renal disease
Pathophysiology - May be due to uremia
due to obstruction by oxalate
crystals, fibrosis or hyperplasia
Micro : Cysts lined by flattened or cuboidal
epithelium that may show focal pseudopapillae with
nuclear enlargement and loss of polarity
• Cysts may contain oxalate crystals
• Surrounding parenchyma shows global
glomerulosclerosis, interstitial fibrosis & tubular atrophy.

15. Glomerulocystic kidney disease
• common in newborns and young children
• associated with ADPKD genes
• BERNSTEIN’S CLASSIFICATION

16. • dilatation of Bowman’s space in the plane of section of two- to threefold that of
normal

17. Tubulointerstitial syndromes +/-
cysts

18. Nephronophthisis
• autosomal recessive
• most frequent genetic cause of ESRD in children and adolescents
• six genes (NPHP1, NPHP2/inversin, NPHP3, NPHP4, NPHP5, and NPHP6) -
nephrocystins, which are expressed in primary cilia, basal bodies, or centrosomes
• inability to concentrate urine, polydipsia, aneuresis, severe anemia, and growth
retardation
• Bilateral
• reduced in size ; granular surface.
• On c/s, the cortex and medulla are both thinned.
The corticomedullary junction – indistinct;
thin-walled, fluid-filled cysts

19. • Tubulointerstitial fibrosis with lymphocytic inflammatory infiltrate, tubular
atrophy, and cyst formation; marked thickening of the tubular basement
membrane (PAS-stained sections)

20. Medullary cystic kidney disease
• rare autosomal dominant disorder
• MCKD1 and MCKD2 genes chromosomes 1q and 16p
• third and fourth decades of life
̴juvenile NPH (-growth retardation and long history of anemia)
normal or moderately reduced in size with small corticomedullary cysts.
• Microscopically, diffuse interstitial inflammation with fibrosis and tubular
atrophy interspersed with hypertrophied and dilated tubules

21. Renal tubular dysgenesis.
• poor development of proximal tubules, early onset and
persistent anuria -oligohydramnios and the Potter
sequence
Inherited RTD is genetically heterogeneous and linked to
mutations in the genes encoding the major components
of the renin-angiotensin system (RAS)

22. Secondary RTD
• Twin-to-twin transfusion syndrome
• Foetal exposure to RAS blockers

23. Bardet-Biedl syndrome
• Primary Features -Rod-cone dystrophy.
Postaxial polydactyly.
Truncal obesity
Learning disabilities.
Hypogonadism (males)/genital abnormalities (females)
Renal anomalies.
• Secondary Features -Speech delay/disorder.
Developmental delay.
Behavioral abnormalities.
Eye abnormalities
Brachydactyly/syndactyly.
Diabetes mellitus.
Orodental abnormalities; craniofacial dysmorphism
Cardiovascular anomalies, Hepatic involvement
Hirschsprung disease
Anosmia.

24. Cystic neoplasms and neoplastic
cysts

25. Cystic nephroma
• benign cystic lesion of the kidney of unknown etiology
• before age 2 and after age 40. (before 2- males, after 40 – females)
• conglomeration of noncommunicating cysts of varying size; pseudocapsule
around cysts- compression of adjacent renal parenchyma
• lined with flattened, cuboidal cells with hobnail-appearing cells

26. • DIAGNOSTIC CRITERIA :
(a) lesion must be multilocular
(b) the cyst for the most part lined by epithelium
(c) the cyst must not communicate with renal pelvis
(d) the residual renal tissue should be essentially normal, except for pressure
atrophy
(e) no fully developed nephrons.
IHC
• cytokeratin 19, cytokeratin AE1/AE3, epithelial membrane antigen
• ovarian-like stroma stain positively for progesterone receptors and estrogen
receptors

27. Mixed epithelial and stromal tumor
• solid and cystic, tan to yellow Well circumscribed but unencapsulated tumor in
renal pelvis
• immunoreactivity for desmin and smooth muscle actin
• MEST – higher stromal to epithelial ratio
prominent ovarian stroma
smaller cysts with phyllodes glands pattern
stromal luteinisation
CN - large cysts, thin septa, and low stromal to epithelial ratio

28. Multilocular cystic renal cell carcinoma
•mean age of 51 years
•excellent outcome
•Gross – encapsulated non communicating
multiloculated lobules filled with gelatinous fluid.
•Micro - lining of cysts may show multilayering,
cells with granular to clear cytoplasm
No expansile growth of clear tumor cells / solid nodules
•Cystic RCC - cystic degeneration of conventional RCC (worse
prognosis)

29. • CD10, vimentin, and epithelial
membrane antigen (EMA).

30. Tubulocystic renal cell carcinoma
• mean age of 60 years
male preponderance
• Gross - circumscribed,
unencapsulated, and cortical in
location.
“bubble-wrap” or “Swiss cheese”
appearance
• Micro - lined by a single layer of
neoplastic cells which range from
flat, hobnail, cuboidal, cylindrical
to columnar. They are separated by
thin, hypocellular fibrous septa
that lack ovarian-type stroma or
desmoplasia,

31. • Immunohistochemically,
positive - markers of PCT (CD10,
carbonic anhydrase IX, vimentin,
AMACR) as well as
distal tubule/collecting duct (CK7, CK19,
parvalbumin, BerEp4).

32. Von Hippel–Lindau disease
• AD
• 3p
• Multiple cysts in the kidneys, pancreas
and genital tract
• Hemangioblastomas
• clear cell renal cell carcinoma,
pheochromocytoma, pancreatic
neuroendocrine tumor, epididymal
cystadenomas and endolymphatic sac
tumors

33. Lymphangioma/hygroma renalis
• Extermely rare type of lymphangioma located
in the pericalyceal area
• multiloculated cyst extending to the
pericalyceal and hilar area covering the ureter
• multicystic lesion with flat endothelial cells
• cytokeratin and calretinin negative
• presence of endothelial lined lymphatic
channels separated by the connective tissue
is the main histologic feature of the disease.

34. Miscellaneous cysts

35. SIMPLE RENAL CYST
• most common
• occurrence increases with age
• Asymptomatic
• translucent, filled with clear serous
fluid and lined by a single layer of
cuboidal or flattened epithelium.
• complicated – thick capsular walls
with hemosiderin-laden macrophages
and atrophic lining epithelium

36. Medullary sponge kidney
• tubular ectasia of the collecting ducts
and cystic formation confined to the
medullary pyramids
• cysts are multiple, small, and limited
to the medullary pyramids and
papillae
• The cysts are lined by collecting duct
epithelium and usually communicate
with collecting tubules
• The interstitium often shows severe
inflammation and scaring, frequently
accompanied by tubular atrophy

37. THANK YOU