Cystic Diseases of the Kidney Dr. Raid Jastania

Objectives By the end of this session the students should be able to: –List the common causes of renal cysts –List the types of polycystic kidney disease –List the types of renal stones and their implications –Understand the pathogenesis of hydronephrosis

Case Presentation

A 40-year-old Chinese man underwent surveillance ultrasonography (US) of the kidneys. He was suffering from chronic renal failure and was on regular haemodialysis for the past six years. The patient was otherwise asymptomatic and his dialysis program was unremarkable.

US scans showed a largely cystic lesion at the lower pole of the right kidney. However, there was a suspicious solid component at the rim of the lesion. Previous US scan performed 6 years ago revealed bilateral small and atrophic kidneys.

Unenhanced CT scan showed a low-density lesion at the lower pole of the right kidney, with a small spike of calcification at its margin. After contrast injection, the lesion was found to be predominantly cystic, but an enhancing solid component was noted at the rim of the cystic wall. Other CT sections confirmed the presence of bilateral atrophic kidneys with multiple cystic changes, compatible with acquired cystic disease of the kidney.

The patient underwent radical nephrectomy and he made an uneventful recovery. Histopathological examination confirmed a renal cell carcinoma in a background of acquired cystic disease of the kidney.

Back to: Cystic Diseases of Kidney

Cystic Diseases of the Kidney Hereditary Developmental Acquired

Simple cyst Simple or multiple Usually cortical 1-5 cm Smooth surface Incidental finding

Dialysis-Associated acquired cyst End-stage kidney, on hemodialysis Cortex and medulla May cause hematuria Increased risk of tumors Occasional adenoma, and renal cell carcinoma

Adult Polycystic kidney Autosomal dominant –PKD1 (polycystin-1) on Chromosome 16 –90% of cases –Cell-cell, cell-matrix adhesion molecule –Both alleles must be lost (second somatic hit) –PKD2 (polycystin-2) on chromosome 4, 10% of cases Multiple expanding cysts Destruction of renal parencyma 10% of chronic renal failure cases

Adult polycystic Kidney Morphology: –Large up to 4 kg –Masses of cysts –Filled with fluid, clear, turbid, hemorrhagic –Micro: Cysts lined by single cuboidal epithelium Atrophy of the kidney

Adult polycystic Kidney Clinical: –Present in the 4 th decade –Flank pain –Mass – intermittent hematuria –Hypertension –Infection –Association: berry aneurysm of brain, cysts in liver, pancreas, others. Diverticular disease. –Slow progression –End stage kidney at age of 50y

Childhood polycystic kideny Autosomal recessive, chromosome 6 Perinatal, neonatal, infantile, juvenile Pulmonary and renal failure Multiple cysts, uniform lining (collecting tubules) Association –Multiple cysts in the liver –Congenital hepatic fibrosis

Dysplastic Kidney

Case Presentation

A 52 year old man presented for evaluation of left flank pain of 1 year duration. He was nonsmoker with a history of left nephrolithotomy for staghorn calculus 20 years back. He had hypertension and ischemic heart disease as co-morbid conditions. On clinical examination patient had a scar of left flank incision with a palpable hard kidney. His urine analysis showed microscopic hematuria and culture was sterile. His renal biochemistry was normal.

On renal ultrasound a staghorn calculus was detected without associated hydronephrosis. Patient underwent transperitoneal laparoscopic nephrectomy. During surgery there were dense perirenal adhesions especially near the hilum. The hilar lymph nodes were also enlarged and densely adherent to the renal vessels. The procedure was electively converted to open surgery via flank incision. The total operating time was 5 hours and 20 minutes with estimated blood loss of 200 ml.

The patient had a smooth post-operative recovery. The histopathological examination of the specimen revealed presence of keratinizing type of squamous cell carcinoma of renal pelvis with metastasis to hilar lymph nodes. Patient was advised postoperative palliative chemo-radiotherapy. After six weeks of surgery patient developed fulminant herpes zoster and expired due to same.

Back to Kidney Stones

Urinary outflow obstruction Occur anywhere in the urinary system Renal stones: common

Urinary outflow obstruction Occur anywhere in the urinary system Renal stones: common Pathogenesis –1. 75% Ca oxalate, or Ca phosphate –2. 15% Mg Ammonium Phosphate –3. 10% Uric acid –4. Rare cystine stones

Renal stones Predisposing factors for Ca stones –1. High urine concentration –2. Hypercalcemia (hyperparathyroidism, vit. D intoxication, sarcoidosis) –3. Hypercalciuria –4. High uric acid in urine –5. hyperoxaluria

Renal stones Predisposing factors for Mg Ammonium phospate stones: –Alkaline urine –Infections, specially proteus, staph

Renal stones Predisposing factors for uric acid stones: –1. Gout –2. Hematologic malignancies eg. Leukemia Predisposing factor for cystine stone –1. Genetic defect in renal transport system for aminoacids

Renal stones Morphology: –Unilateral 80% –Occur in renal pelvis, calyces, bladder –Staghorn stone: Mg ammonium phosphate Clinical –Asymptomatic, massive hydronephrosis –Renal colic: flank pain, radiate to groin –Gross hematuria –infections

Primary Oxalosis

Case Presentation

A 78-year-old cachectic woman presented with an enormous abdominal tumour, which, according to the patient, had slowly increased in diameter. Medical history was unremarkable except for a hysterectomy >30 years before. A CT scan revealed a giant cystic tumour filling almost the entire abdominal cavity. It was analysed by two independent radiologists who suspected a tumour originating from the right kidney and additionally a cystic ovarian neoplasm.

A diagnostic and therapeutic laparotomy was performed: the tumour presented as a cystic, 35 × 30 × 25 cm expansive structure adhesive to adjacent organs without definite signs of invasive growth. The right renal hilar vessels could finally be identified at its basis. Another tumourous structure emerged in the pelvis originating from the ovary was also resected.

The histopathological examination revealed a >15 kg hydronephrotic right kidney, lacking hardly any residual renal cortex parenchyma. The second specimen was identified as an ovary with regressive changes and a large partially calcified cyst. There was no evidence of malignant growth.

Back to: Hydronephrosis

Hydronephrosis Dilatation of renal pelvis and calyces Atrophy of the renal parenchyma Caused by obstruction: partial, complete, unilateral or bilateral Causes –Congenital (hereditary, developmental) –Acquired

Hydronephrosis Congenital –Atresia of urethra or ureter –Valve of urethra or ureter –Renal torsion –Kinking of ureter

Hydronephrosis Acquired: –Foreign body: stone –Tumors: prostate, bladder –Inflammation: prostatitis, urethritis, ureteritis, retroperitoneal fibrosis –Neurogenic: spinal cord damage –Pregnancy: mild, reversible

Hydronephrosis Pathogenesis –Obstruction – high pressure – leak of fluid in the interstitium – fluid back to lymphtics –High pressure – dilated collecting system – defect in the function of the tubules – poor concentration of urine – polyuria –Higher pressure – vascular stasis, congestion – decrease blood flow – decrease glomerular filtrate – renal insufficiency

Hydronephrosis Pathogenesis –Irreversible damage occurs in 3 weeks of complete obstruction –Or 3 months of partial obstruction

Hydronephrosis Morphology: –Unilateral: large kidney (20cm) –Distended pelvis and calyces –Atrophy of the parenchyma –Hydronephrosis, hydroureters –If sudden and complete: Mild dilation Loss of renal function

Hydronephrosis Micro: –Tubular dilatation, interstitial edema, mild inflammation –Atrophy, fibrosis –Late glomerular damage –When sudden and complete: papillary necrosis –Infection is common

Hydronephrosis Clinical: –Bilateral, complete – Anuria –Bilateral, incomplete – polyuria –Unilateral: detected late when both kidneys are affected

Objectives By the end of this session the students should be able to: –List the common causes of renal cysts –List the types of polycystic kidney disease –List the types of renal stones and their implications –Understand the pathogenesis of hydronephrosis

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