[1774] Dense Deposit Disease Mimicking Acute Post-Infectious Glomerulonephritis

J Hicks, D Kelly, E Mroczek-Musulman, S Goldstein, K Eldin. Texas Children's Hospital & Baylor College of Medicine, Houston, TX; Children's Hospital & University of Alabama, Birmingham, AL

Background: Dense deposit disease (DDD) has been recently reviewed (Mod Pathol 2007:20:606-16) with the conclusion that DDD is a distinct entity separate from membranoproliferative disease. DDD demonstrates 5 patterns: 1) membranoproliferative; 2) mesangial proliferative; 3) crescentic; 4) acute proliferative/exudative; 5) unclassified. Crescentic and acute proliferative/exudative patterns occurred between 3 and 18 years of age. While other DDD patterns had a wide age range (3-67yrs) with 90% occurring in those <30 years of age. DDD disease may mimic acute post-infectious glomerulonephritis (AGN) on light, immunofluorescence (IF) and electron microscopy (EM).
Design: DDD (crescentic and acute proliferative/exudative patterns) mimicking AGN on initial presentation were identified in 6 patients at 2 pediatric hospitals (3M:3F, age range 4-12 yrs; AGN symptoms: hematuria, proteinuria, elevated Cr). Following medical management for AGN, the patients had relapses or persistent renal symptoms leading to repeat renal biopsies (1 to 4 years after initial diagnosis).
Results: Initial biopsies demonstrated either an acute proliferative/exudative pattern (3/6 with endocapillary proliferation with neutrophils) or a crescentic pattern (3/6 with >50% of glomeruli with crescents). PAS and trichrome staining revealed hump-like membranous deposits. IF showed C3-positive globular to granular membranous deposits. EM demonstrated subepithelial hump-like deposits and infrequent subepithelial deposits with no mesangial interposition. Repeat biopsies demonstrated thickened capillary loops with PAS-positive membranous ribbons. IF showed globular to granluar C3-positive membranous deposits, and discontinuous linear C3-positive membranous deposits. EM revealed subepithelial hump-like deposits, and intramembranous electron dense transformation of the lamina densa (intramembranous dense deposits).
Conclusions: In the pediatric age group, DDD may present as crescentic and acute proliferative/exudative patterns with subepithelial hump-like deposits detected by special stains, IF and EM. These DDD patterns may be confused with AGN due to the lack of ribbons of intramembranous dense deposits. Persistent or recurrent renal disease in these patients requires repeat renal biopsy to ascertain whether there is well-established acute proliferative/exudative or crescentic DDD that initially mimicked AGN.
Category: Ultrastructural

Monday, March 9, 2009 1:00 PM

Poster Session II # 244, Monday Afternoon