Abstract: TH-PO0184
Collapsing FSGS as a Paraneoplastic Manifestation of Rectal Adenocarcinoma in an APOL1-Negative Patient
Session Information
- Onconephrology: Anticancer Therapies, PTLD, Paraneoplastic Diseases, and More
November 06, 2025 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Onconephrology
- 1700 Onconephrology
Authors
- Brito, Germana Alves, AC Camargo Cancer Center, São Paulo, SP, Brazil
- de Amorim, Fernanda Oliveira, AC Camargo Cancer Center, São Paulo, SP, Brazil
- Pereira, Benedito J., AC Camargo Cancer Center, São Paulo, SP, Brazil
- Malheiros, Denise M., Universidade de Sao Paulo Faculdade de Medicina, São Paulo, SP, Brazil
- Neves, Precil D., Hospital Alemao Oswaldo Cruz, São Paulo, SP, Brazil
- Imanishe, Marina Harume, AC Camargo Cancer Center, São Paulo, SP, Brazil
- De Andrade, Luis Andre Silvestre, AC Camargo Cancer Center, São Paulo, SP, Brazil
- Baptista, Aline Lourenco, AC Camargo Cancer Center, São Paulo, SP, Brazil
Introduction
Collapsing FSGS is a rare glomerular lesion, linked to HIV, drugs, autoimmune diseases and APOL1 risk alleles. Its occurrence as a paraneoplastic phenomenon, especially in solid tumors, is uncommon described.
Case Description
We report the case of a 48-year-old man recently diagnosed with rectal adenocarcinoma who presented with serum creatinine (sCr) 2.44 mg/dL and 2+ proteinuria. At nephrology consultation, renal function had worsened (sCr 2.99 mg/dL) with nephrotic syndrome (albumin 2.6 g/dL; proteinuria 13.7g/24h). Work-up revealed negative serum anti-PLA2R antibody, autoimmune tests (ANA, anti-dsDNA, C3/C4, RF, ANCA), infectious serologies (HIV, hepatitis B/C) and normal immunoelectrophoresis of serum and urine proteins. Ultrasound revealed a small right kidney and normal left. Kidney biopsy demonstrated collapsing FSGS with podocyte hypertrophy, endothelial swelling, glomerulosclerosis (3/4), moderate interstitial fibrosis and negative immunofluorescence. APOL1 genotyping revealed no risk alleles. Given the chronic changes and presumed paraneoplastic etiology, immunosuppressive therapy was withheld. The patient was managed with diuretics and renin-angiotensin system blockade. Oncologic treatment included colostomy, radiotherapy and 5-fluorouracil-based chemotherapy. At 9-month follow-up, he exhibited reduction in proteinuria (4.13g/24h), resolution of anasarca and stable kidney function (sCr 3.44 mg/dL).
Discussion
This case supports collapsing FSGS as a likely paraneoplastic manifestation of rectal adenocarcinoma, given its temporal association, exclusion of secondary causes, negative APOL1 and nephrotic syndrome improvement after cancer treatment.