Abstract: SA-PO210
Membranous-Like Glomerulopathy with Masked IgG Kappa Deposits (MGMID) in a Patient with Sezary Syndrome
Session Information
- Onconephrology: Immunological Cross-Talk
November 04, 2023 | Location: Exhibit Hall, Pennsylvania Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Onconephrology
- 1700 Onconephrology
Authors
- Kodavanti, Chandra Kumar Mallick, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, United States
- Schmidt, Darren W., University of New Mexico Health Sciences Center, Albuquerque, New Mexico, United States
- Kuperman, Michael Benjamin, Arkana Laboratories, Little Rock, Arkansas, United States
- Garcia, Pablo, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, United States
Introduction
MGMID is a rare pattern of glomerulonephritis (GN) that has recently been described in the literature and is characterized by sub-epithelial and/or mesangial immune deposits (Figure 1) that are masked to routine immunofluorescence but strongly stain for IgG and Kappa light chain after protease digestion. Commonly seen in young females < 40 years of age with a mean 24-hour proteinuria of 3.5 g (range 0.5-12.8) and have weakly positive antinuclear antibody titers. We present a patient with Sezary syndrome and nephrotic range proteinuria, and was found to have MGMID. To our knowledge, MGMID in Sezary Syndrome has not been reported yet.
Case Description
65 year-old female with Sezary Syndrome on Mogamulizumab and type 2 Diabetes Mellitus (DM) presented for evaluation of albuminuria and was found to have nephrotic range proteinuria. She denied symptoms of volume overload. Her DM was well controlled. Her serological work up (Table 1) was negative. Kidney biopsy showed MGMID. She was treated with losartan and empagliflozin. Proteinuria decreased from 5.2 gm/day to 2.5 gm/day. Renal function continues to be stable, and she is currently continuing treatment with biweekly mogamulizumab for Sezary syndrome.
Discussion
This case emphasizes the need for research into this unique pattern of GN to figure out etiology and treatment. At this time, anti-proteinuric medications seem to be a reasonable option. Frequent presence of C3-only staining by routine immunofluorescence (IF) microscopy could lead to misdiagnosis as C3 GN in the absence of protease digested paraffin IF evaluation thereby underscoring the need to use paraffin IF. Serum Amyloid P (SAP) is also key to the diagnosis.
Laboratory values
| Serum creatinine- 0.65 mg/dL (0.50-1.04); urine protein-creatinine ratio- 5.25 gm/gm; urine albumin-creatinine ratio- 3.7 gm/gm; urine analysis- 7 RBCs, 1 WBC; Hepatitis panel- Negative; Kappa-lambda ratio – 1.50; C3 and C4 are normal; ANA- negative; ANCA- negative; Hemoglobin A1c-6.3 |
A. PAS: Mild mesangial expansion within an enlarged glomerulus
B. H&E: Acute tubular injury with epithelial cell sloughing and epithelial simplification
C. Kappa (paraffin): Granular capillary and mesangial staining on protease digested paraffin-embedded tissue "unmasking" the immune deposits
D. Serum Amyloid P: Granular capillary and mesangial staining with SAP confirming the diagnosis of MGMID