Page 689 - Textbook of Pathology, 6th Edition

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Figure 22.21 A, Focal GN. The characteristic feature is the cellular proliferation in some glomeruli and in one or two lobules of the affected
glomeruli i.e. focal and segmental proliferative change. B, C, Focal segmental glomerulosclerosis. The features are focal and segmental involvement
of the glomeruli by sclerosis and hyalinosis and mesangial hypercellularity .

in the form of hyalinosis and sclerosis. Currently, the
MORPHOLOGIC FEATURES. By light microscopy, the condition is divided into 3 groups: CHAPTER 22
single most important feature in focal GN is the
abnormality seen in certain number of glomeruli and i) Idiopathic type. This group comprises majority of cases.
generally confined to one or two lobules of the affected It is found in children and young adults with presentation
glomeruli i.e. focal and segmental glomerular involvement of nephrotic syndrome. It differs from minimal change
(Fig. 22.21,A). The pathologic change most frequently disease in having non-selective proteinuria, in being steroid-
consists of focal and segmental cellular proliferation of resistant, and may progress to chronic renal failure. Immuno-
mesangial cells and endothelial cells but sometimes fluorescence microscopy reveals deposits of IgM and C3 in
necrotising changes can be seen. The condition must be the sclerotic segment.
distinguished from focal and segmental glomerulo- ii) With superimposed primary glomerular disease. There
sclerosis (discussed below). may be cases of FSGS with superimposed MCD or IgA
By immunofluorescence microscopy, widespread nephropathy. Those associated with MCD show good
mesangial deposits of immunoglobulins (mainly IgA with response to steroid therapy and progression to chronic renal
or without IgG), complement (C3) and fibrin are failure may occur after a long time. The Kidney and Lower Urinary Tract
demonstrated in most cases of focal GN.
iii) Secondary type. This group consists of focal segmental
CLINICAL FEATURES. The clinical features vary according sclerotic lesions as a secondary manifestation of certain
to the condition causing it. Haematuria is one of the most diseases such as HIV, diabetes mellitus, reflux nephropathy,
common clinical manifestation. Proteinuria is frequently mild heroin abuse and analgesic nephropathy.
to moderate but hypertension is uncommon. The hallmark of pathogenesis of FSGS is injury to visceral
epithelial cells that results in disruption of visceral epithelial
Focal Segmental Glomerulosclerosis cells and resultant nephron loss.
(Synonyms: Focal Sclerosis, Focal Hyalinosis)
MORPHOLOGIC FEATURES. By light microscopy,
Focal segmental glomerulosclerosis (FSGS) is a condition in depending upon the severity of the disease, variable
which there is sclerosis and hyalinosis of some glomeruli and number of glomeruli are affected focally and segmentally,
portions of their tuft (less than 50% in a tissue section), while while others are normal. The affected glomeruli show
the other glomeruli are normal by light microscopy i.e. solidification or sclerosis of one or more lobules of the tuft.
involvement is focal and segmental. The incidence of FSGS Hyalinosis refers to collection of eosinophilic,
has increased over the last decades and is currently homogeneous, PAS-positive, hyaline material present on
responsible for about one-third cases of nephrotic syndrome the inner aspect of a sclerotic peripheral capillary loop.
in the adults. Mesangial hypercellularity is present in appreciable

ETIOPATHOGENESIS. FSGS was previously believed to number of cases. In addition, to glomerular changes, there
be a variant of MCD with accentuation of epithelial damage is interstitial fibrosis and infiltration by mononuclear