Secondary focal glomerulosclerosis not due to HIV

The idiopathic and familial forms of focal glomerulosclerosis, and the similar lesion that occurs in association with HIV infection, are dealt with elsewhere in this supplement. This article highlights conditions where FSGS develops, apparently, as a phenomenon secondary to another defined pathology. It may occur in a setting of normal renal mass associated with (i) an immunological aberration such as thymoma, or (ii) in a non-immunological setting associated with increased intra-glomerular pressure or deposition of inappropriate material. FSGS may also be found (iii) in association with a reduced renal mass that may, for example, follow an ischaemic renal insult. The pathogenetic mechanism(s) involved remain unclear.