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Preparing your E-Poster
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E-Poster Submission Deadline
Please prepare and upload your E-Poster no later than March 14, 2026 11.59PM CET. After this date, you will no longer be able to prepare and upload your E-poster and it will not be displayed and accessible on the congress website.
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Abstract titles should be brief and reflect the content of the abstract.
Propylthiouracil (PTU) is a well-known cause of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). The overlap between lupus nephritis (LN) and AAV has been increasingly recognized; however, cases of PTU-related overlap are rare. Distinguishing these two conditions can be challenging if both serological and histopathological features coexist. Herein, we report a case of PTU-associated nephritis with overlapping LN and AAV features.
A 31-year-old woman treated with PTU for Graves’ disease for four years was found to have microscopic hematuria and proteinuria during a routine checkup four months ago. Subsequently, renal dysfunction was detected at a local clinic, and both myeloperoxidase (MPO)-ANCA and proteinase 3-ANCA were positive. She also tested positive for antinuclear and anti-double-stranded DNA antibodies, along with hypocomplementemia (low C3 and C4 levels). Despite the discontinuation of PTU, renal dysfunction and urinary abnormalities persisted, prompting a renal biopsy.
Light microscopy revealed mild proliferative mesangial glomerulonephritis and focal segmental sclerosis. Immunofluorescence revealed full-house immune deposits in the glomeruli, consistent with lupus nephritis (LN) (class III). In contrast, the tubulointerstitial area showed extensive inflammatory cell infiltration, marked tubulitis, and peritubular capillaritis. Notably, no immune complex deposition was detected in the interstitial lesions, and medullary vasculitis was observed in the renal tubules. These findings suggest that glomerular lesions reflect classical LN, whereas interstitial and medullary vascular inflammation represent ANCA-mediated processes. Immunosuppressive therapy with prednisolone, mycophenolate mofetil, hydroxychloroquine, and belimumab led to improved renal function and urinary findings.
This case presents an overlap between PTU-induced LN and ANCA-associated vasculitis. In the presence of overlapping serological features, histopathological findings, particularly immune complex deposition and medullary vasculitis, provide important diagnostic clues for differentiating between the two conditions. Recognizing these features may aid the differential diagnosis, management, and prognosis of PTU-induced nephritis.
