RENAL PATHOLOGY LEARNING

Type II Membranoproliferative

Glomerulonephritis

by

Franco Ferrario and Maria Pia Rastaldi

Dr Franco Ferrario
Renal Immunopathology Center
San Carlo Borromeo Hospital
Milan, Italy

 

 

Dense deposit disease (DDD) was first reported in 1962 and is characterized by the presence of an extremely electron dense transformation of the glomerular basement membrane. In the early 1970s,  DDD was classified as subtype II of membranoproliferative glomerulonephritis (MPGN). Over the last thirty years, marked differences in etiology and pathogenesis between Type I MPGN and DDD have become apparent. Recent observations have shown that DDD can be seen with markedly different light microscopy appearances with apparently different prognostic significance.

Type II MPGN is characterized by a dense homogenous deposition along the glomerular basement membrane and in the mesangium. Deposits can be different, in dimension and diffusion, even among the glomeruli of a given biopsy. When deposition is mild, ultrastructural examination is fundamental for diagnosis.

 

mgp2001

 

The glomerular basement membrane is diffusely thickened by dense homogenous deposits, very evident at higher magnification.

 

mgp2002

 

The same dense deposits frequently involve the Bowman’s capsule.

 

mgp2003

 

The tubular basement membranes may contain the deposits as well.

 

mgp2004

 

Type II MPGN shows variable histological features. The most common form is similar to the classic form of Type I MPGN, with intense mesangial proliferation and mesangial matrix increase.

 

mgp2005

 

Also in Type II MPGN there are cases of focal and segmental membranoproliferative lesions.

 

mgp2006

 

In some cases only minimal lesions can be observed and differential diagnosis has to be made from minimal change disease, stage I MGN and some cases of IgA GN.

 

mgp2007

 

Although at higher magnification it is possible to recognize the segmental thickening of the capillary wall, an accurate diagnosis is only possible by electron microscopy examination.

 

mgp2009

 

Segmental extracapillary proliferation can be present.

Rare cases can show diffuse circumferential extracapillary proliferation. Type II MPGN diagnosis is difficult when the glomerular tuft is compressed by the extracapillary proliferation.

 

mgp2010

 

C3 immune deposits are intense along the glomerular basement membrane and in the mesangium. This peculiar immunohistological pattern has been variably described as linear, pseudolinear, ribbon-like, granular or nodular. The deposits are also found on the Bowman’s capsule and on some tubular basement membranes.

 

mgp2011

 

Electron microscopy is essential for diagnosis and shows the linear ribbon-like deposits in the glomerular basement membrane (x 1700).

Ribbon-like deposits alternate with short normal tracts of basement membrane. (x 3600 - x 3600).

 

mgp2012

 

Ribbon-like deposits can be of various thickness (x 6000 - x 6000).

 

mgp2013

 

The Bowman’s capsule and the tubular basement membrane show the same electrondense deposition. (x 3600)

 

mgp2014

 

QUESTIONS

 

REFERENCES
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2. Muda AO, Barsotti P, Marinozzi V: Ultrastructural histochemical investigations of „dense deposit disease“. Pathogenetic approach to a special type of mesangiocapillary glomerulonephritis. Virch Arch 413: 529-537, 1988.
3. Kashtan CE, Burke B, Burch G, et al: Dense intramembranous deposit disease: a clinical comparison of histological subtypes. Clin Nephrol 33: 1-6, 1990.
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5. Mullins RF, Russell SR, Anderson DH et al : Drusen associated with aging and age-related macular degeneration contain proteins common to extracellular deposits associated with atherosclerosis, elastosis, amyloidosis, and dense deposit disease. FASEB J 14:835-846, 2000.
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