Renal Pathology Laboratory

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Renal Pathology Laboratory

• Dr. Gilbert

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CASE 1

• Clinical History
• A 10 year old caucasian girl was brought by her
  parents to their family physician. History
  revealed that the child had a sore throat for
  about 10 days prior to the office visit. Initial
  laboratory tests ordered by the family physician
  revealed an elevated BUN and creatinine. A
  urinalysis showed hematuria with dysmorphic
  RBC's. The patient is referred to a nephrologist.
  The nephrologist, based upon the usual course of
  this illness, elects to follow the patient.
  However, two weeks later, the C3 is still
  decreased.
• Pathologic Findings
• A renal biopsy was performed next.

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Slide 1.1At medium power, a glomerulus is shown
here with HE stain.
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Slide 1.2At higher power, a glomerulus is shown
here with HE stain.
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Slide 1.3The pattern of immunofluorescence of
the glomerulus is shown here with antibody to
human complement (C3).
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Slide 1.4The electron micrograph of the
glomerulus is shown here. Note the electron dense
subepithelial "humps" above the basement membrane
and below the epithelial cell. The capillary
lumen is filled with a leukocyte demonstrating
cytoplasmic granules.
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Case 1

• Questions
• What tests should be ordered?
• What diagnosis is suggested at this point?
• What is the differential diagnosis?
• What additional laboratory tests should be
  ordered?

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CASE 1 Post-infectious glomerulonephritis

• Slides 1.1 and 1.2
• What are the light microscopic findings?
• An endocapillary proliferative glomerulonephritis.
  The glomerulus shows increased cellularity, with
  many neutrophils present.
• Slide 1.3
• What does the immunofluorescence staining show
  for C3 (staining was negative with C1q, IgM, and
  IgA)? Staining for IgG is /-.
• Immunofluorescence shows a coarse granular
  pattern of staining along the capillary basement
  membranes with C3.
• Slide 1.4
• What does the electron microscopy show?
• There are prominent subepithelial "humps" and
  there are PMN's in the capillary lumens. The
  findings are most consistent with post-
  streptococcal glomerulonephritis.

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Case 1 Answers

• What tests should be ordered? Antistreptolysin O
  (ASO) - elevated Complement C3 - decreased.
• What diagnosis is suggested at this point?
  Post-streptococcal glomerulonephritis.
• What is the differential diagnosis?
• post-streptococcal glomerulonephritis
• IgA nephropathy
• membranoproliferative glomerulonephritis (I or
  II)
• SLE
• What additional laboratory tests should be
  ordered? C3 nephritic factor - negative (tends to
  rule out MPGN II) ANA - negative (tends to rule
  out SLE).

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CASE 2

• Clinical History
• A 25 year old male works in a military fuel
  depot. He began having respiratory difficulty
  along with red-tinged sputum. Two months later,
  he had increasing malaise and flank pain. He went
  to see the base physician. The patient then
  developed very rapid onset of renal failure with
  hematuria within three days.
• Pathologic Findings
• A renal biopsy was performed.

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Slide 2.1At medium power, a glomerulus is shown
here with HE stain.
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Slide 2.2At medium power, another glomerulus is
shown here with HE stain. Most of the glomeruli
had this appearance.
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Slide 2.3The immunofluorescence pattern is seen
here with antibody to fibrinogen.
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Slide 2.4The immunofluorescence pattern is seen
here with antibody to IgG
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Case 2

• Questions
• What tests and procedures would you order?
• What is the differential diagnosis?
• What additional laboratory tests can be ordered?

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CASE 2 Goodpasture's syndrome

• Slides 2.1 and 2.2
• What does the light microscopy show?
• Crescents
• Slide 2.3
• What does the immunofluorescence show with
  staining for fibrinogen?
• The crescent within Bowman's space stains for
  fibrinogen, consistent with injury leading to
  leakage of the fibrinogen that stimulates
  epithelial cell proliferation and crescent
  formation.
• Slide 2.4
• What does the immunofluorescence show with
  staining for IgG?
• There is a linear pattern of staining along the
  glomerular basement membrane with IgG. In most
  cases of Goodpasture's syndrome with rapidly
  progressive glomerulonephritis there is linear
  staining with IgG, but IgA and IgM can also be
  present.

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Answers

• What tests and procedures would you order?
• Chest x-ray - infiltrates are present, but no
  cavitary lesions or mass lesions
• Sputum culture - negative for pathogens
• PPD - negative
• Urinalysis - many RBC's
• What is the differential diagnosis?
• Goodpasture's syndrome
• Vasculitis (Wegener's granulomatosis, SLE,
  polyarteritis nodosa)
• IgA nephropathy
• What additional laboratory tests can be ordered?
• Anti-neutrophil cytoplasmic antibody (ANCA) -
  negative (tends to exclude Wegener's)
• anti-GBM antibody - positive

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CASE 3

• Clinical History
• A young male in his early 20's had a routine
  checkup by his family physician, which included a
  urinalysis. The urinalysis revealed a few RBC's.
  Physical examination was non-contributory. A
  repeat urinalysis shows dysmorphic RBC's and RBC
  casts, but no WBC's.
• Pathologic findings
• Though one diagnosis in particular is most
  strongly suspected and has no specific treatment,
  a renal biopsy was performed for confirmation of
  the diagnosis.

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Slide 3.1At medium power, a glomerulus is shown
here with HE stain. The arrow points to one
mesangial region.
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Slide 3.2The immunofluorescence pattern is shown
here. This would be the same whether the antibody
was to IgA or complement C3.
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Slide 3.3The microscopic appearance of the urine
sediment is shown here. Note the appearance of
many of these RBC's, compared to two relatively
normal RBC's at the center left of the right
panel.
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Case 3

• Questions
• What additional history do you want to know?
• What is the differential diagnosis?
• What additional laboratory tests could be
  ordered?
• What diagnosis would you consider if the patient
  had presented with petechiae and purpura of the
  skin?

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CASE 3 IgA nephropathy

• Slide 3.1
• What does the light microscopy show?
• There is mesangial proliferation. The capillaries
  appear normal.
• Slide 3.2
• What does the immunofluorescence show that
  represents the pattern seen with staining for
  both IgA and C3?
• Mesangial deposition of IgA and C3. The C1q, IgM,
  and IgG are negative.
• Slide 3.3
• What does the urinalysis microscopic examination
  show?
• These are dysmorphic red blood cells.

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Answers

• What additional history do you want to know?
  There was no history of trauma. He had no
  dysuria. He had a recent "flu-like" illness.
  There is no family history of renal disease. One
  maternal uncle is deaf.
• What is the differential diagnosis?
• IgA nephropathy
• Alport's syndrome
• Vasculitis (Wegener's granulomatosis, SLE,
  polyarteritis nodosa)
• Urinary tract infection
• What additional laboratory tests could be
  ordered?
• ANA - negative
• ANCA - negative
• Urine culture - negative
• What diagnosis would you consider if the patient
  had presented with petechiae and purpura of the
  skin? Henoch-Schonlein purpura

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CASE 4

• Clinical History
• A 15 year old female seen by her family physician
  because of increasing lethargy. She had a recent
  history of the "flu". The child's condition does
  not improve after several weeks, so a renal
  biopsy is then done.

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Slide 4.1At medium power, a glomerulus is shown
here with HE stain.
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Slide 4.2At medium power, a glomerulus is shown
here with Masson's trichrome stain.
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Slide 4.3At medium power, a glomerulus that
appears normal with HE stain is shown here.
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Slide 4.4An electron micrograph is shown here.
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Case 4

• Questions
• What additional history should be obtained?
• What laboratory tests should be ordered?
• What is the differential diagnosis?
• What additional laboratory tests could be
  ordered?
• What do you do next?

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CASE 4 Focal segmental glomerulosclerosis (FSGS)

• Slides 4.1 and 4.2
• What does the light microscopy show (Slide 4.2 is
  stained with a trichrome stain)?
• Sclerosis in a segmental pattern in some
  glomeruli
• What diagnosis would you consider if the patient
  had been a 1 year old child with a history of
  failure to thrive and edema, urinalysis showing
  hyaline casts and oval fat bodies, proteinuria of
  3.7 gm/day, hypoalbuminemia and increased serum
  cholesterol?
• Minimal change disease
• Slide 4.3
• What does the HE appearance of the glomerulus
  show?
• The glomerulus is normal by light microscopy.
• Slide 4.4
• What is the essential feature seen in the
  electron micrograph?
• Effacement of foot processes of podocytes.

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Answers

• What additional history should be obtained? There
  is no family history of congenital diseases,
  including sickle cell disease. The child is being
  fed well.
• What laboratory tests should be ordered?
  Urinalysis - 3 protein, everything else
  negative it is a "selective proteinuria" with
  just albumin present 24 hr urine protein is 1.5
  gm.
• What is the differential diagnosis?
• Minimal change disease
• Focal segmental glomerulosclerosis
• Membranoproliferative glomerulonephritis
• SLE (rare)
• What additional laboratory tests could be
  ordered?
• C3 is normal
• C1q is negative
• ANA is negative
• What do you do next? Treat with corticosteroids
  and see if the child improves.

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CASE 5

• Clinical History
• A 41 year old male is found to have proteinuria
  on urinalysis performed as part of a yearly
  checkup by his physician. The dipstick urinalysis
  showed no blood, glucose, or ketones. The
  microscopic urinalysis revealed only 1 RBC/hpf
  and no WBC/hpf. Physical examination findings
  include 1 pitting edema of the lower extremities
  to the knees. His blood pressure is 130/80. The
  rectal examination reveals no masses, but the
  stool guaiac is positive. The lungs are clear to
  auscultation and percussion. Palpation of the
  abdomen reveals no masses, and bowel sounds are
  present. Additional laboratory testing revealed a
  24 hour urine protein of 4.1 gm. His serum
  creatinine was 4.2 with BUN of 40. He was
  referred to a nephrologist, and a renal biopsy
  was performed.

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Slide 5.1At high power, a glomerulus is shown
here with HE stain.
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Slide 5.2At high power, a glomerulus is shown
here with the Jones silver stain.
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Slide 5.3The immunofluorescence pattern is seen
here with antibody to IgG.
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Slide 5.3The electron micrograph of the
glomerulus is seen here.
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Case 5

• Questions
• What is the differential diagnosis?
• What additional laboratory testing would be
  useful?
• What additional workup is necessary in this case?
  
• What is the pathogenesis of the disease seen
  here?

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CASE 5 Membranous glomerulonephritis (MGN)

• Slides 5.1 and 5.2
• What does the light microscopic appearance
  demonstrate (Slide 5.2 is a Jones silver stain)
  in all glomeruli?
• There is thickening of the glomerular capillary
  loops, but the cellularity is not increased. The
  silver stain demonstrates "spikes" along the
  basement membrane of the capillaries.
• Slide 5.3
• What is the pattern seen on immunofluorescence
  with antibody to IgG?
• There is a diffuse granular pattern of staining.
• Slide 5.4
• What are the features demonstrated by electron
  microscopy?
• There is thickening between the capillary
  basement membrane and overlying epithelial cells
  having fused foot processes with deposition of
  electron dense material and interposition of
  lighter basement membrane material (which formed
  the "spikes" seen on the silver stain).

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Answers

• What is the differential diagnosis?
• This is nephrotic syndrome in an adult. The most
  common cause is membranous glomerulonephritis,
  but minimal change disease, focal segmental
  glomerulosclerosis, and membranoproliferative
  glomerulonephritis can also occur. Nephrotic
  syndrome can also occur with systemic diseases
  such as diabetes mellitus, infections such as
  hepatitis B, malignancies, and amyloidosis. SLE
  would be uncommon in this setting, but could
  occur. About 85 of cases of membranous GN are
  idiopathic.
• What additional laboratory testing would be
  useful?
• An ANA was negative. The serum IgG was slightly
  decreased, and serum complement levels were
  normal. His serum glucose was 110 mg/dl. He is
  HbsAg negative.
• What additional workup is necessary in this case?
  
• The positive stool guaiac suggests
  gastrointestinal hemorrhage. A colonoscopy was
  performed, and a 5 cm irregular exophytic mass
  found in the cecum. The most common malignancies
  associated with adult membranous GN are
  melanomas, lung cancers, and colon cancers.
• What is the pathogenesis of the disease seen
  here?
• MGN is a chronic antigen-antibody mediated
  disease in which the immune complexes are
  deposited in the glomerular capillaries. The
  antigen may be within the glomerular capillary
  (in idiopathic cases) or extrinsic to the kidney
  (in secondary causes).

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CASE 6

• Clinical History
• A 34 year old male is found to have 1
  proteinuria on urinalysis performed as part of a
  pre-employment physical examination. The dipstick
  urinalysis showed no blood or ketones, but the
  glucose was 2. Physical examination was
  unremarkable. His blood pressure was 135/85.

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Slide 6.1At high power, a glomerulus is shown
here with HE stain.
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Slide 6.2At high power, a glomerulus is shown
here with PAS stain.
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Slide 6.3A complication of diabetes mellitus is
shown here with HE stain.
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Slide 6.3Another complication of diabetes
mellitus is shown here with HE stain.
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Case 6

• Questions
• What underlying disease process is suggested by
  these findings?
• What additional laboratory testing would be
  helpful?
• What other complications could be present, given
  his underlying disease? Examples of additional
  complications are shown in Slides 6.3 and 6.4.

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CASE 6 Diabetic Nephropathy

• Slide 6.2
• What light microscopic appearance is shown in
  Slides 6.1 and 6.2 (Slide 6.2 is a PAS stain)
  that was present in many glomeruli?
• Nodular glomerulosclerosis is evidenced by the
  presence of rounded masses of pink hyaline
  material in the mesangial cores of glomerular
  tufts. This material stains bright red with PAS.
  Also, a small arteriole adjacent to the
  glomerulus in Slide 6.2 shows hyaline
  arteriolosclerosis.

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Answers

• What underlying disease process is suggested by
  these findings?
• Diabetes mellitus. Proteinuria occurs in about
  half of patients with either type I or type II
  diabetes mellitus, usually about 1 to 2 decades
  after initial appearance of clinical diabetes
  mellitus, and suggests a greater likelihood for
  progression to chronic renal failure in 5 years.
• What additional laboratory testing would be
  helpful?
• A fasting blood glucose greater than 140 mg/dl as
  measured on two occasions will document the
  hyperglycemia indicative of diabetes mellitus.
  The presence of ketonuria would suggest type I
  diabetes mellitus, but the lack of ketones is not
  specifically indicative of type II diabetes
  mellitus. If he were overweight, then type II is
  more likely.
• What other complications could be present, given
  his underlying disease? Examples of additional
  complications are shown in Slides 6.3 and 6.4.
• Slide 6.3 demonstrates numerous neutrophils in
  and around renal tubules, indicative of acute
  pyelonephritis. Slide 6.4 shows many round cells,
  including lymphocytes, and more significantly,
  plasma cells, that can be found with chronic
  pyelonephritis. Urinary tract infections are more
  common and severe in patients with diabetes
  mellitus. Diabetics can also develop papillary
  necrosis. Accelerated atherosclerosis can lead to
  marked nephrosclerosis, either arterial or
  arteriolar. The term diabetic nephropathy is
  often used to denote the spectrum of pathologic
  lesions that can be found in kidneys in patients
  with diabetes mellitus types I and II.