I.
RENAL PATHOLOGY
THE
GLOMERULOPATHIES
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I.
PATHOLOGY RENAL
LAS
GLOMERULOPATIAS
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MORPHOLOGIC
FLOWCHART FOR THE GLOMERULOPATHIES
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ALGORITMO
MORFOLOGICO PARA LAS GLOMERULOPATIAS
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Back to
Glomerulopathies
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Back
to renal Pathology
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Regresar a
Glomerulopatias
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Regresar a Patologia
Renal
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GLOSSARY.
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GLOSARIO.
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When the pathologist is
confronted with the renal biopsy he needs a morphologic
classification (catalogue of morphologic patterns) to make
an histological differential diagnosis and to mentally work
with a flowchart. This pure morphologic classification and
flowchart are not available in the literature. Hybrid
(clinical-pathological) classifications are not adequate for this
purpose. The introduction of a morphologic classification and flowchart
is an attempt to facilitate the morphologic diagnosis and
not to substitute the established clinical nomenclature
which should prevail and be used when communicating with the
clinicians. The use of
epoxy techniques (High Resolution Light Microscopy or HRLM) preparing the slides facilitates the
use a flow chart since a single section reveals most of the
diagnostic features (0.2 um or larger), no special stains
needed and TEM is immediately available from the same epoxy
block. This is not possible with the paraffin sections.
Our morphologic classification is founded on basic lesions
and not on complications or extent of the lesion. Sometimes
complications are more prominent than the basic lesions and
some of them may appear as primary GP. However, to make an
accurate morphologic diagnosis all efforts should be made to
find the basic underlying lesions. During their evolution
most of the Glomerulopathies may be focal or diffuse, or may
or may not have complications (thrombosis, necrosis,
inflammation, cell proliferation, membrano proliferative
change or MPC, sclerosis, fibrosis, glomerular collapse).
Therefore, to use the extent of a lesion or a complication
as a parameter to classify morphologically the Glomerulopathies may be inaccurate and misleading however,
these parameter may be important when grading or staging the
lesion. Every time a strange morphologic pattern appears,
the possibility of morphologic pattern variation should be
considered rather than "fabricating new diseases".
Variations of the patterns described here are included in page "b" of the material presented.
1. Whatever methods are used to study the renal biopsy, the
first step
is to decide
what renal compartment is predominantly involved.
2. In most nephropathies the
glomerular compartment is
predominantly involved. If so, first rule out the presence of
immune deposits. To be sure that there are obvious deposits
and not just trapped immunoproteins (visible by
immunomethods but invisible by LM, HRLM and TEM), HRLM-TEM
studies must be used for confirmation especially, in chronic
GP where trapping of immunoproteins is prominent. The nature
of the deposits is better studied by Immunohistology. It is
more difficult to see the deposits in paraffin sections stained with
tri chrome stain. This morphologic pattern with obvious immune
deposits is called here
"GLOMERULONEPHRITIS" OR "GN"
3. If there are no obvious immune deposits (especially in
children), other non immune deposits (metabolic or other)
should be ruled out. Special stains, HRLM and TEM are the
best methods to detect these lesions. This group is called here
"GLOMERULOSIS" or "GO"
4. If there are no obvious deposits (immune or non-immune) a
derangement of the glomerular structures should be explored. Special
stains, HRLM and TEM are of much help. It is more difficult
to see these morphologic alterations in paraffin sections
stained with silver (Jones) or PAS. This groups is called here
"GLOMERULAR DYSMORPHISM" or "GD".
5.
"Complication:
A morbid process or event occurring during a disease that is
not an essential part of the disease, although it may result
from it or from independent causes"
(Stedman's Medical
Dictionary).
As in other organs, the glomeruli
in the kidney may present lesions that are not
essential part of the glomerulopathy since these may also
result also from independent causes. Complications may be
superimposed on any glomerulopathy and some times these may
appear as independent (idiopathic) morphologic patterns. The
following lesions may be classified as acute complications:
Necrosis, thrombosis, inflammation, cell proliferation
(intra or extra capillary), acute glomerular capillary
collapse, mesangiolysis.
This group is called here
"GLOMERULITIS" or "GL".
Chronic complications may be: regeneration,
repair, sclerosis, fibrosis, reduplication of the GBM, chronic
glomerular capillary collapse, FSGS??. This groups is called here
GLOMERULOSCLEROSIS or "GS).
When a complication predominates, all efforts (clinical and
morphologic) should be made to discover the underlying
glomerulopathy before calling it "Crescentic", "Proliferative"
"Necrotizing", "Idiopathic", other.
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Cuando el Patólogo es
confrontado con la biopsia renal, necesita una
clasificación morfológica (un catálogo
de patrones morfológicos) para hacer un
diagnóstico diferencial histológico y
mentalmente trabajar con un algoritmo. Esta
clasificación morfológica y este algoritmo no
aparecen en la literatura moderna. Las clasificaciones
hibridas no son apropiadas para este propósito.
La introducción
de esta clasificación y algoritmo pretende facilitar
el diagnóstico morfológico y no sustituir la
nomenclatura clínica vigente que debe prevalecer y
ser usada cuando uno se comunica con los clinicos.
El uso de
Histotecnología por epoxis (MOAR) facilita el uso de
un algoritmo por que un solo corte revela casi todas las
lesiones diagnosticas y no se necesitan coloraciones
especiales. Esto no es posible con los cortes de
parafina.
Nuestra clasificación morfológica se
fundamenta en lesiones básicas y no en complicaciones
o extensión de la lesión. Algunas veces las
complicaciones son mas prominentes que las lesiones
básicas y pueden presentarse como GP primarias. Sin
embargo, para hacer un diagnóstico morfológico
adecuado se deben hacer todos los esfuerzos para encontrar
las lesiones básicas subyacentes. Durante su
evolución la mayoría de las glomerulopatias
pueden ser focales o difusas y pueden o no presentar
complicaciones (trombosis, necrosis, inflamación,
proliferación celular, cambio membranoproliferativo,
esclerosis, fibrosis). Por lo tanto usar la extensión
de una lesión o sus complicaciones como
parámetros de clasificación morfológica
puede ser impreciso y engañoso. Sin embargo estos
parámetros son importantes cuando se da un grado o
estadio a la lesión. Cada vez que se encuentra un
patrón morfológico extraño, se debe
considerar la posibilidad de variación del
patrón morfológico corriente y
"no fabricar
una nueva enfermedad". Estas variaciones están
incluidas en la página "b" del material presentado.
1. Cualquiera sea el método usado para estudiar la
biopsia renal, la primera etapa es decidir cual
compartimento renal esta mas afectado.
2. Usualmente es el compartimiento glomerular
el mas comprometido. Primero,
uno debe descartar la presencia de depósitos inmunes
(Glomerulonephritis o GN).
Para estar seguro de que hay depósitos obvios y no
solamente immunoproteinas atrapadas (visible por
inmunometodos pero invisibles por ML, MOAR y MET) su
presencia se debe confirmar por MOAR-MET, especialmente en
GP crónicas. Inmunohistología es el
método de preferencia cuando se trata de identificar
la naturaleza de los depósitos. Es mucho mas dificil
ver los depósitos en cortes de parafina con
tricrómico.
3. Si no hay depósitos inmunes obvios (especialmente
en niños), se deben buscar depósitos no
inmunes (generalmente metabólicos)
(Glomerulosis o GO).
Coloraciones especiales, MOAR-MET son invaluables para este
propósito.
4. Si no hay depósitos de ninguna clase, se deben
buscar alteraciones morfológicas de los componentes
glomerulares
(Dismorfismo
glomerularo DG). HRLM-TEM y
coloraciones especiales son los métodos mas adecuados
para este propósito. Es mas dificil descubrir estas
alteraciones en corte de parafina con plata (Jones) y
PAS.
5.
"Complicacion:
Un proceso u evento morbido que ocurre en una enfermedad y
que no es parte esencial de esa enfermedad, pero puede
resultar de ella o independientemente por otras
causas"
(Diccionario Medico de
Stedman).
Como en otros organos,
las complicaciones en el rinon pueden estar superpuestas
sobre cualquier glomerulopatía y algunas veces pueden
aparecer como patrones morfológicos independientes.
Pueden clasificarse como complicaciones agudas
(Glomerulitis o GL):
Necrosis, trombosis, inflamación y
proliferación celular, colapso capilar glomerular
agudo, mesangiolisis. Las complicaciones crónicas
serian
(Glomerulosclerosis o GS):
Regeneración, reparación, esclerosis,
reduplicación de la MBG , colapso capilar glomerular
crónico, fibrosis, EGFS. Cuando una
complicación predomina, se deben agotar todos los
esfuerzos clínicos y morfológicos, para
descubrir la glomerulopatía subyacente antes de
llamarla "Proliferativa", "Por semilunas" "Necrotizante",
"Idiopática", otros.
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HOW TO USE THIS
FLOWCHART
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You must have methods to detect
deposits of immunoproteins, metabolic substances and methods
to study the structure of the glomerular components. You
must have other specialized methods for difficult cases or a
referral laboratory to send consults.
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Adequate renal
biopsy: For diagnosis > 10 Gl. For quantitative analysis
> 20 Gl.
The first step in examining a
renal biopsy is to determine if the sample is adequate. Most
renal GPs have focal or focally accentuated lesions. If only
10% of the glomeruli in the kidneys are involved by a focal
process, a biopsy sample with ten glomeruli has a 35%
probability of missing the diagnostic lesions. When 25% of
the glomeruli are involved it is still a 5% chance of
missing the diagnostic lesions. The number of glomeruli in
the biopsy is even more crucial for the assessment of the
grade (activity) and stage (chronicity) of the process.
Hence, a biopsy with at least 20 to 25 glomeruli is
sufficient for this purpose . The report of the pathologist
must include the # of glomeruli in the biopsy to give the
clinician an idea on how accurate the pathologists report
may be according the size of the biopsy.
In
Renal Pathology, diagnostic accuracy and precise
quantitation of the lesions, depend on the adequacy of the
sample.
To
confirm the adequacy of the sample, there is no substitute
for the microscopic examination of the renal biopsy at bed
side.
IT IS
THE RESPONSIBILITY OF THE PATHOLOGIST TO PRODUCE AN ACCURATE
MORPHOLOGIC DIAGNOSIS. HOWEVER, IT IS THE RESPONSIBILITY OF
THE NEPHROLOGIST OR TRANSPLANT SURGEON TO PROVIDE HIM WITH
AN ADEQUATE BIOPSY TO MAKE THAT ACCURATE DIAGNOSIS
POSSIBLE.
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Methods
used
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Light Microscopy (HRLM or
PLM)
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Immuno Histology (FM or
IP)
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Electron Microscopy
(TEM)
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Other
methods
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Biopsy findings:
In this flowchart the
glomerular lesions are the main clues to start building a
morphologic diagnosis but, the other compartments should be
always studied in detail since they may have important
diagnostic lesions.
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Lesions predominantly
glomerular. See
below:-------------
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Lesions predominantly
tubular.
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Lesions predominantly
interstitial.
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Lesions predominantly
vascular.
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Not in this site.
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Not in this site.
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Not in this site.
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A.
The presence of well organized immune deposits is
characteristic of
"GLOMERULONEPHRITIS
or GN". Deposits must be
visually detected (HRLM-TEM), FM alone is not accurate, but
immunohistology is essensial when the immunoproteins need to
be differentiated. HRLM-TEM recommended for the confirmation
of Glomerulonephritis.
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Location of the Immune
Deposits.
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Link
& Glomerulopathy
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Other
lesions
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New Standardized
name
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Immunohistology
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Mesangial, para
mesangial.
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GN1.
IgA
(Berger's), HS, (Aberrations of the pattern :IgG, IgM, C3,
C1q).
Other GNs: Post
infectious GN, MPGN, Plasma cell dyscrasias.
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Segmental scars. HS
has also, crescents, subendothelial deposits, necrosis.
Mesangial cell proliferation.
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Mesangial GN
(MSGN)
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Usually IgA, C3. Often
IgG, occasionally IgM. HS has also fibrin. (Aberrations of
the pattern may show IgG, IgM, C3, C1q, other
GN).
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GN5.
Mesangial SLE.
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Few PP deposits may be
seen. Mesangial cell proliferation.
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Pleomorphic Panglom.
GN (PPGN grade I)
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IgG + all Ig. Tissue
ANA may be + with IgG.
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GN8.
Amyloidosis
vs Fibrillary GN. Fibrillar material in mesangium and
GBM.
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Amyloid : Pos. for
thioflavin T, crystal violet, congo red (polarized).
Segmental spikes. Fibrillary GP: Neg. for
all.
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Fibrillar GN
(FIGN)
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AL: +L or +K. +IgG,
+C3.
AA: - Ig. Specific amyloid Abs available.
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GN7.
Light or heavy
chain GN. Dense nodular mesangium and lamina densa (inner
part).
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Usually also dense and
granular or ribbon like TBM.
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Nodular GN
(NOGN).
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Monoclonal K or
L
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Sub
epithelial
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GN4.
Membranous
GN: has diffuse string bead (rosary).
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SLE MBGN has same
morphology. May have mesangial deposits.
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Membranous GN
(MBGN)
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IgG & C3.
Sometimes IgM. IgA in SLE.
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GN2.
Acute
proliferative GN has diffuse (but segmental) humps and heavy
infiltrate of PMNs.
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May have focal or
diffuse MPC with mesangial & sub endothelial deposits
(MPGN I),
e/m cell
proliferation
&
crescents.
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Acute Proliferative GN
(APGN):
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IgG, C3. Rarely IgM or
IgA.
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GN5.
Diffuse
Lupus GN has focal or diffuse scanty sub epithelial deposits
and PP deposits.
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Has pleomorphic pan
glomerular deposits. May have diffuse or
focal
MPC
&
crescents.
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Pleomorphic
Panglomerular GN (PPGN grades II & III)
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IgG, IgM, C3, C1q, IgA
fibrin
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Intra membranous
(ribbon like) and mesangial.
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GN6.
Dense Deposit
GN. Has diffuse GBM and TBM with interrupted dense lamina
densa (C3). Has early MPC.
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May have humps and few
PMNs. Rarely dense nodular mesangium. May have
crescents.
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Dense deposit GN
(DDGN).
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Ribon-like C3 along
GBM. Granular C3 in mesangiumC3.
Usually no
Ig.
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GN7.
Light or heavy
chain GN. Mesangial deposits with nodular mesangium and
dense inner part of lamina densa.
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Usually also dense and
granular or ribbon like TBM. Capillary hyaline
thrombi.
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Nodular GN
(NOGN).
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Monoclonal K or
L
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Intra membranous
(granular)
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GN4.
MBGN Stages
II-III.
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Has diffuse string
bead (rosary) intra-epithelial deposits.
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Membranous GN
(MBGN)
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IgG & C3.
Sometimes IgM. IgA in SLE.
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GN2.
APGN, resolving or unresolved.
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Humps and few PMNs are
also present.
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Acute Proliferative GN
(APGN):
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IgG, C3. Rarely IgM or
IgA.
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GN5.
PPGN
(SLE)
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Has also PP
deposits.
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Pleomorphic
Panglomerular GN (PPGN grades II & III)
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IgG, IgM, C3, C1q, IgA
fibrin
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GN2:
MPGN III
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Has associated MBGN or
APGN.
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MBGN or
APGN
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Same
as MBGN or
APGN
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Sub
endothelial.
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GN3.
MPGN. Has sub
endo. deposits and early,
diffuse
MPC.
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Mesangial cell
proliferation. Crescents.
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Membranoproliferative
GN (MPGN).
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Mesangial and
subendothelial C3, IgG. Less frequent:IgM, C1q, C4, IgA
properdine,
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GN5.
SLE GN.
Pleomorphic pan glomerular deposits.
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May have MPC, cell
proliferation, necrosis and crescents.
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Pleomorphic
Panglomerular GN (PPGN grades II & III).
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IgG, IgM, IgA, C3,
C1q.
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GN8.
Amyloid,
Fibrillary GN. Fibrillar material.
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Mesangial lesions.
Segmental spikes with fibrillar material.
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Fibrillary GN
(FIGN).
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Fibrillary GN: IgG,
C3.
AL Amyloid: L or K?
AA Amyloid: Trapped Ig.
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GN9.
Plasma cell
dyscrasias with tactoids, crystaloids; Cryoglobulinemias and
Macroglobulinemias have hyaline capillary thrombi & MPC.
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Cast nephropathy has
no glomerular deposits but has laminated tubular casts (may
have crystals) and tubular giant cells.
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Tactoid-Crystaloid GN
(TCGN)
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CG
Macroglob: IgM-k
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Pleomorphic-Pan glomerular
Deposits.
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GN5.
Lupus GN,
Classes II-VI.
GN1. (HS). Others.
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Cell proliferation,
necrosis, crescents, MPC, sclerosis, fibrosis. Intra
cytoplasmic microtubules. Tubulitis.
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Pleomorphoic
Panglomerular GN (PPGN)
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Tissue ANA
+.
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No specific
pattern.
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GN10.
Unclassified GN. GN distorted by superimposed
process (like crescents).
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The deposits do not
have a recognizable pattern. These are usually chronic
GNs.
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Unclassified GN
(UCGN).
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Non specific
patterns.
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C.
Pauci-immune structural changes of the glomerular components
are characteristic of
Glomerular
Dysmorphism (GD).
Glomerular structures
must be visualized. Special stains, HRLM-TEM
recommended.
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Morphologic
change
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Link
and
glomerulopathy.
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Other
lesions.
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Standardized
name
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Other diagnostic
features..
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Diffuse effacement of
podocytes
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GD
1.
Minimal Change
Disease
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In adults
nephrosclerosis.
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Epithelial Cell GD
(ECGD)
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May be Idiopathic
(Children) or secondary (Adults).
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Focal segmental
glomerulosclerosis + diffuse effacement of
podocytes
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GD
2.
Idiopathic
Focal Segmental Glomerulosclerosis
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Ischemic
nephrosclerosis. Is this also a chronic
complication??
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Focal Segmental GD
(FSGD)
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May be Idiopathic
(Children) or secondary to chronic GP
(Adults).
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Nodular Mesangium,
thick BMs and hyalinosis
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GD
3.
Diabetic
Nephropathy.
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Marked glomerular and
arteriolar hyalinosis. Thick irregular TBM.
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Nodular GD
(NOGD)
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Glycemia, glycosilated
hemoglobin, tolerance tests.
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Thin GBM (<250
nm)
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GD
4. Thin
Basement Membrane Nephropathy.
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GBM may be normal or
have other GP (IgA).
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Thin Membrane GD
(TMGD).
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Family
history.
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Lamination, thinning
and thickening and irregular GBM.
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GD
5.
Alport's Dis. 2. May be seen in MSGN, TMGD but is
segmental.
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1. May have tubular
and interstitial foam cells. 2. Underlying GP is
present.
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Laminar GD
(LAGD).
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1. GBM negative to Ig
and anti-GBM Ab. Family history. 2. Ig present in
GN.
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Mesangial degenerative
changes.
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GD
6. Diffuse
(Infantile) Mesangial Sclerosis.
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May have fetal
epithelial cells and FSGS.
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Mesangial GD
(MSGD)
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Family
history.
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Intra membranous and
mesangial interstitial collagen.
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GD
7. Nail
Patella Glomerulopathy
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Nephrosclerosis.
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Nail Patella GD
(NPGD)
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Multiple skeletal and
nail abnormalities.
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Sub endothelial
collagen type III.
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GD
8.
Fibroplastic
Glomerulopathy or Collageno-fibrotic GP.
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MPC.
Nephrosclerosis.
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Fibro Plastic GD
(FPGD)
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Positive for
anti-collagen type III Ab.
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Glomerular
cysts.
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GD 9. Glomerulocystic
disease.
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Associated to
ADPKD
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Dysplastic GD
(DYGD)
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ADPKD,
Tuberosclerosis.
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Non specific
lesion
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GD10.
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Unclassified GD
(UCGD).
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D.
COMPLICATIONS IN THE
GLOMERULOPATHIES:
"Complication: A morbid process
or event occurring during a disease that is not an essential
part of the disease, although it may result from it or from
independent causes"
(Stedman's Medical Dictionary)
As in other organs, the
glomeruli in the kidney may present lesions that are
not essential part of the glomerulopathy since these may not
be always present and may also result from independent
causes. Inflammation, necrosis, thrombosis, acute capillary
collapse, mesangiolysis and cell proliferation (intra or
extra capillary) may be considered
acute
complications.
Regeneration and repair, sclerosis, chronic capillary
collapse, fibrosis, membrano proliferative change (MPC),
hyalinosis and FSGS ??, may be considered
chronic
complications.
Complications may be focal or diffuse, segmental or global
therefore, the extent of a complication does not modify its
definition. As in other organs in the kidney, complications
may or may not be superimposed on other GP (idiopathic vs.
secondary). All complications superimposed on other GPs are
described with those GPs
(GN, GO and GD
(See
Suggested Classification of
glomerulopathies).
The idiopathic complications (without underlying GP) are
described as separate GPs as they sometimes are seen in the
renal biopsy. But also the complications resulting from
extra glomerular pathology (thrombotic microangiopathy,
vasculitis) or systemic disease (anti GBM ab) with no other
renal lesion but the "glomerular complication" (Crescents,
necrosis, thrombosis). I believe that it is necessary
to group all of these similar lesions in one group for the
benefit of the morphologic differential diagnosis. The
complications without an underlying glomerulopathy (even if
they have extra glomerular lesions or systemic
disease) are abbreviated with four digits using the
sub fix GL
(Glomerulitis) for the
acute complications, GS
(Glomerulosclerosis) for
the chronic complications.
To facilitate the morphologic differential diagnosis all
complication are placed in a separate chapter however, when
communicating with the clinical personnel. The Pathology
Report must follow as close as possible the current clinical
nomenclature: Secondary complications (with known underlying
glomerulopathy or nephropathy) are labeled (reported) with
the name of the original GP (or NP) followed by the %
glomeruli affected with the complication (Diffuse
SLE GN with 60% fibro epithelial crescents (30% with
necrosis and 20% glomerulosclerosis). Or, Vasculitis (PAN)
with 60% crescents (20% with necrosis) and 10%
glomerulosclerosis. Most complications with no underlying GP
or NP, are reported as idiopathic crescentic GL with 40%
epithelial crescents, no necrosis. Unless the etiology is
known (Anti GBM GL): Anti GBM GL with 75% crescents (25%
with necrosis).
Sometimes differentiating the GPs with complications
is very difficult since some times the process is so
destructive that the original GP is difficult to recognize.
It is also common to see a single lesion (necrosis,
thrombosis, crescents) in the biopsies of different
glomerulopathies (thrombotic microangiopathy, vasculitis,
anti GBM GL). Some other times the glomerulopathy may have
most of the complications in the same renal biopsy.
Therefore, the pathologist must be aware of the variability
and overlapping of these non-specific lesions
(complications) and that clinical information becomes
crucial for the differential diagnosis of disease.
When a complication predominates the biopsy, all methods
available (including clinical information) should be used to
R/O underlying glomerulopathy, extra glomerular or systemic
disease.
For the benefit of the reader and to facilitate the
morphologic differential diagnosis, a column labeled "All
Glomerulopathies with this complication" (with traditional
names) is added in the chart below with all the GPs (GN, GO,
GD, GL) most frequently associated with each pertinent
complication.
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ACUTE
COMPLICATIONS
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Lesions.
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Primary
(Idiopathic) Complications.
Traditional
name.
Standardized
name.
|
Comments.
|
All
Glomerulopathies with this
complication.
(Traditional names are
used)
|
|
Abnormal # (> 4)
mesangial cells. May or may not have obvious immune
deposits. IgM and C3 may be positive but not visible by HRLM
or TEM. Increase in mesangial matrix.
|
GL1.
Idiopathic
Mesangial Proliferative GN.
Mesangial
Glomerulitis (MSGL) (Pauci immune)
|
This lesion is usually
superimposed on other glomerulopathies. However it may
be idiopathic.
|
GN:
SLE, HS & IgA (and aberrations: C3, C1q, IgM, IgG, etc),
MPGN I, Post Infect. GN,
Endocarditis.
GO: All with non
immune (metabolic)
deposits.
GD: Minimal Ch.
dis., FSGS,
others.
GL:
Idiopathic Mesangial
Proliferative GN.
|
|
Thrombosis
(Glomerular, arterial, arteriolar), endothelial swelling,
mixoid intima, fibrin and fragments of red cells in wall of
Bv. MPC, ischemic sclerosis.
|
GL2.
Thrombotic
Microangiopathies.
Thrombotic
Microangiopathic Gomerulitis (TMGL).
|
Fragmented red cells
and fibrin are usually seen in the thrombi or wall of the
Bv. Crescents may be present.
|
GN:
SLE with Anti-phospholipid
S., SBE, IgA,
HS.
GO:
When assoc. with HUS, TTP,
Malignant HT,
others.
GD:
When assoc. with HUS, TTP,
Malignant HT,
others.
GL:
HIV, rejection, PAPS,
systemic infections, Scleroderma, HUS, TTP, Malignant HT,
Vasculitis, drug toxicity, Idiopathic Thrombotic
microangiopathy.
|
|
Crescents (extra
capillary cell proliferation). Irregular fibrosis with
synechiae. Free fibrin in Bowman's space.
|
GL3.
Anti GBM
Ab GN (Goodpasture) , Idiopathic Crescentic GN. Others.
Crescentic
glomerulitis (CRGL).
|
In the literature CRs
are separated in 3 groups of GPs: Anti GBM GN, Immune
complex GN, Pauci-immune GN (ANCA Assoc GPs).
See
Crescentic GP.
|
GN:
SLE, Post infectious GN, HS
& IgA GPs, MPGN I & II, Fibrillary GN,
Membranous GN, Mixed
cryoglobulinemia.
GO: In severe cases but,
usually
rare.
GD: Alport's, Malignant FSGS
(collapsing
GP).
GL: Anti GBM GN,
vasculitis, systemic infections, visceral abscesses,
endocarditis, Idiopathic crescentic GN.
|
|
Vasculitis with
necrosis, crescents, interstitial inflammation,
fibrosis.
|
GL4.
GP with
Vasculitis.
Vasculitic GL (VAGL)
|
ANCA is a
serologic test should not be used to make morphologic
diagnosis of crescentic GN or
vasculitis.
|
GN:
Mixed
cryoglobulinemia, SLE, HS purpura,
GO: Vasculitis are
rare.
GD: Vasculitis are
rare.
GL: Polyarteritis
nodosa, Wegener's granulomatosis, Churg-Strauss
syndrome, other vasculitis are rare.
|
|
Focal segmental
necrosis and focal segmental scars.
|
GL5.
Necrotizing
GN.
Necrotizing GL
(NEGL).
|
It is usually
associated to other lesions especially CRGPs. However in
small biopsies may be seen as an idiopathic
lesion. Do not
confuse post necrotic scars with FSGS.
|
GN:
SLE, Post infectious GN, HS
& IgA GP, MPGN I & II, Membranous GN, Mixed
cryoglobulinemia.
GO:
In severe cases but, usually
rare.
GD:
Alport's, Malignant FSGS
(collapsing
GP).
GL: Anti GBM GN,
vasculitis, systemic infections.
abscesses, endocarditis, idiopathic crescentic GN,
Idiopathic Necrotizing GN.
|
|
Lymphoid infiltration
in glomeruli. May be followed by MPC (MPGS).
|
GL6.
Transplant
Glomerulitis.
Lymphoid glomerulitis (LYGL).
|
LYGL is usually
followed by membranboproliferative change
(MPSC)
|
GN:
SLE.
GO:
Not
described.
GD: Not
described.
GL: Allograft
Glomerulitis and allograft glomerulopathy.
Vasculitis.
|
|
Endothelio Mesangial
cell proliferation (endocapillary cell
proliferation).
|
GL7.
Pauci-immune
endotheliomesangial
Glomerulitis.
Endothelio-Mesangial GL (EMGL).
|
Usually associated to
underlying GP. In small biopsies the underlying
glomerulopathy may not be visible.
|
GN:
APGN, IgA-HS, SLE,
Thrombotic
MA.
GO: Not
described.
GD: Not
described.
GL:
Vasculitis, toxemia, necrotizing GN.,
Idiopathic
endocapillary proliferative GN.
|
|
Infection,
microorganisms, fibrin, PMNs, necrosis.
|
GL8.
Infective
Glomerulitis.
Acute Infective Glomerulitis (AIGL)
|
Several
infections may give glomerular lesions with the already
described patterns. Sometimes, the microorganisms may be
seen in the glomeruli.
|
GL: Candidiasis,
aspergillosis, bacterial infections, cryptococcus, acute
pyelonephritis.
|
|
Mesangiolysis
|
GL9.
Glomerular
Mesangiolysis.
Mesangiolytic Glomerulitis (MLGL)
|
Rarely seen in renal
biopsies. Frequently seen in autopsy material in patients
with severe congestive heart failure. It is usually
associated to micro aneurysms.
|
GN:
Plasma cell
dyscrasias.
GO:
Not
described?
GD:
Diabetic
nephropathy, congestive heart failure,
GL:
Thrombotic
MA, hypertension, rejection, radiation,
chemotherapy, viral infections, toxics, drugs,
other.
Idiopathic Mesangiolysis.
|
|
Pauci-immune Focal
proliferative GN.
|
GL10.
Focal
Glomerulonephritis.
Focal
Proliferative Glomerulitis (FPGL)
|
Usually a variation of
the stereotypical pattern. In small biopsies may be seen as
an idiopathic pattern. Also frequently associated to
focal necrotizing GL.
|
GN:
SLE, Post infectious GN, HS
& IgA GP, MPGN I & II, Membranous GN, Mixed
cryoglobulinemia.
GO:
In severe cases but, usually
rare.
GD:
Alport's, Malignant FSGS
(collapsing
GP).
GL: Anti GBM GN,
vasculitis, systemic infections, visceral abscesses,
endocarditis, idiopathic crescentic GN, Idiopathic
Necrotizing GN.
|
|
Glomerular Capillary
Collapse and prominent visceral epithelial cells (Collapsing
glomerulopathy).
|
GL11.
Collapsing
Glomerulopathy.
Collapsing
Glomerulitis (COGL).
|
Acute collapse of
capillaries is frequently associated with tubulo
interstitial pathology. Chronic capillary collapse is seen
in all ischemic sclerosing GP. (See GS
below).
|
GN:
Plasma cell dyscrasias,
CRGN.
GO:
??
GD: FSGS
(AIDS).
GL: viral infections,
pyelonephritis, transplant GP, vasculitis, , thrombotic
microangiopathies, vascular pathology,
Idiopathic collapsing GP.
|
|
Unclassified Acute
Glomerular Complication.
|
GL12:
Unclassified
Glomerulitis (UCGL).
|
|
|
|
CHRONIC
COMPLICATIONS
|
|
Lesions.
|
Primary
(Idiopathic) Complications.
Traditional
name.
Standardized
name.
|
Comments.
|
All
Glomerulopathies with this
complication.
(Traditional
names are used)
|
|
Reduplication of GBM.
(Mesangial interposition and Endothelial
splits.
|
GS1.
Pauci
immune membranoproliferative Glomerulonephritis
(Pauci-immune MPGN).
Membranoproliferative
Glomerulosclerosis (MPGS) or Membranoproliferative Change
(MPC)
|
MPC is a non-specific
reaction of repair and may be seen in any chronic GP. Always
look for underlying lesions. See also:
"Membranoproliferative
Change" (MPC).
|
GN:
MPGN I, II, III, SLE, CRGN. Other
GN.
GO: Chronic stages.
GD: Chronic
stages.
GL: Thrombotic
microangiopathies, vasculitis, rejection, radiation.
Other GL. Idiopathic, pauci-immune MPGN.
|
|
Glomerulo Sclerosis.
(BM collagen).
|
GS2.
Glomerulosclerosis.
Ischemic
Glomerulosclerosis
(ISGS).
|
The term is usually
applied to benign glomerulosclerosis
(nephrosclerosis).
|
GN:
Superimposed on Chronic
stages.
GO: Superimposed on Chronic
stages.
GD: Superimposed on Chronic
stages.
GL: Superimposed on
Chronic stages.
Hypertension, aging, Idiopathic ischemic
sclerosis.
|
|
Glomerular Fibrosis
(Interstitial collagen. Types I and III).
|
GS3.
Glomerular
Fibrosis.
Fibrotic GS (FIGS).
|
Scars (interstitial
collagen) secondary to necrosis-thrombosis, crescentic GN,
pyelonephritis, rejection, other.
|
GN:
CRGN, Complicated with focal
necrosis.
GO: Complicated with
necrosis.
GD: Nail Patella GD,
Fibroplastic GP or Collageno-fibrotic GP (Collagen III).
GL:
Paunci immune CRGN,
Vasculitis, necrotizing GN., Post necrotic
glomerular scars.
|
|
Focal Segmental
Glomerulosclerosis ?.
|
GS4.
Secondary
Focal Segmental (global) Glomerulosclerosis
??.
Focal
Segmental Glomerular Sclerosis (FSGS).
|
Is FSGS a
complication ??. Like other complication FSGS may be
idiopathic or secondary.
|
Secondary:
GN:
MBGN, IgA GN,
GO:
Chronic stages.
GD:
Diabetic GS, Chr. rejection, Ischemic sclerosis.
GL:
Chronic stages.
Idiopathic: Classic FSGS.
|
|
Glomerular
hyalinosis.
|
GS5.
Glomerular
hyalinosis.
Hyalinosis
Glomerulitis (HYGL).
|
Hyalinosis is not
well understood but appears to be associated with the
sclerosing process. C3 and IgM are usually positive but no
obvious deposits.
|
GD:
FSGS, diabetes
mellitus, antitransplant drug cytotoxicity, hypertension,
ESRD.
|
|
Unclassified
Glomerular Chronic Complication.
|
GS6.
Unclassified
Glomerular Sclerosis (UNGS)
|
|
|
|
|
|
|
|