Akademik Veri Yönetim Sistemi
37th European Congress of Pathology, Vienna, Avusturya, 6 - 10 Eylül 2025, cilt.487, ss.450, (Özet Bildiri)
Background & Objectives: LECT2 (leukocyte cell-derived chemotaxine-2) amyloidosis is a rare and often underdiagnosed subtype of amyloidosis that usually presents with renal-limited disease. This case series highlights four renal biopsy-confirmed cases of LECT2 amyloidosis, including one with extrarenal involvement and accompanying monoclonal gammopathy.
Methods: Four renal biopsies diagnosed as LECT2 amyloidosis between 2022 and 2024 were retrospectively reviewed. Immunohistochemical and immunofluorescence studies were performed to characterize amyloid deposits. Clinical and laboratory data were retrieved when available.
Results: Three male patients (aged 70, 54, and 48) were referred from external centres with no available clinical information. All showed amyloid deposition in the glomerular mesangium, arteriolar walls, and interstitium, with exclusive LECT2 positivity on immunohistochemistry. No staining was observed for AA, kappa, lambda, transthyretin, gelsolin, or β2-microglobulin. The fourth case was a 65-year-old woman with no known comorbidities, presenting with nephrotic-range proteinuria (4471 mg/day). Her renal function tests were normal. Kidney biopsy revealed diffuse amyloid deposition in the kidney parenchyma which was positive for LECT2 by immunohistochemistry. However, immunofluorescence showed a lambda monotypic light chain restriction. Subsequent bone marrow biopsy was also characterized by lambda-restricted monotypic plasma cell proliferation and, notably, diffuse LECT2 deposition in the vascular walls. Bone marrow remission was achieved with six cycles of Daratumumab plus CyBorD therapy, however, proteinuria persisted at 2340 mg/day.
Conclusion: Although often considered renal-limited, LECT2 amyloidosis may involve other organs, as demonstrated by vascular LECT2 deposition in the bone marrow of one of our patients. The presence of monoclonal gammopathy may lead to misclassification of the disease as AL amyloidosis and interferes with the correct diagnosis. Accurate subtyping through detailed immunophenotyping is essential to ensure appropriate management and avoid unnecessary treatment.