Abstract: SA-PO727
Primary and Secondary Podocyte Infolding and Microparticles: An Ultrastructural Diagnosis
Session Information
- Pathology and Lab Medicine: Clinical
November 09, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Pathology and Lab Medicine
- 1601 Pathology and Lab Medicine: Basic
Author
- Agrawal, Vinita, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, UP, India
Background
Podocyte Infolding Glomerulopathy (PIG) is a recently described pathologic entity with ultrastructural alterations of glomerular basement membrane (GBM) and podocytes. It is characterized by the presence of podocyte invaginations, podocyte infolding, spherical microparticles and microtubules in the GBM. It was first reported from Japan. Since then there are case reports describing it more commonly among women with membranous nephropathy and autoimmune diseases. This study describes the author’s experience of finding PIG-like changes in a spectrum of glomerular diseases.
Methods
The ultrastructural features in renal biopsies received for routine electron microscopy during a 6-month period, in a tertiary care referral center in North India, were evaluated for PIG-like changes. Biopsies showing both podocyte infolding and microtubules and microparticles were included. The changes were evaluated as segmental/global and focal/diffuse.
Results
On ultrastructure, focal and segmental podocyte infolding and microparticles were seen in four biopsies including Membranous Nephropathy with FSGS (n=2), post-transplant IgAN with transplant glomerulopathy (n=1), and unspecified connective tissue disease (n=1). Electron dense deposits were present in all. Mean age was 29 years (range 20-47) with three males. Diffuse PIG was seen in a renal biopsy from a 43-year old woman, diagnosed as FSGS on light microscopy. No electron dense deposits were seen. The microparticles were round or oval and the size varied widely, measuring 40-170 nm. All biopsies showed diffuse foot process effacement and evidence of GBM remodeling with lamellation and splitting of lamina densa. Nephrotic proteinuria was present in all patients.
Conclusion
As is true for other pathological morphological entities in renal glomerular diseases like FSGS, MPGN etc., PIG is also a morphological; pattern which may exist in a primary diffuse form with no electron dense deposits, predominantly in females and a secondary form with focal and segmental changes associated with other glomerular diseases with electron dense deposits without any gender predilection. It is useful to recognize that PIG-like changes can be seen in various glomerular diseases and this may be referred to as focal and segmental-PIG (FSPIG) instead of PIG.