Ana Teresa Domingos
1* 
, Sara Barreto
2, Eduarda Carias
1, Ana Cabrita
1, Helena Viana
3,4 , Mário Góis
3,4 1 Department of Nephrology, Centro Hospitalar e Universitário do Algarve, Faro, Portugal
2 Department of Nephrology, Hospital Garcia de Orta, Almada, Portugal
3 Department of Nephrology, Hospital de Curry Cabral, Centro Hospitalar e Universitário de Lisboa Central, Portugal
4 Laboratory of Renal Morphology, Hospital de Curry Cabral, Centro Hospitalar e Universitário de Lisboa Central, Portugal
Abstract
Anti-neutrophil cytoplasmic antibody (ANCA) disease remains a diagnostic challenge due to the
heterogeneity of possible clinical presentations. We present the case of a 63-year-old white male with
a known history of ANCA-associated vasculitis (AAV) with anti-myeloperoxidase antibodies (MPO)
– mainly with respiratory manifestations – treated with corticosteroids and cyclophosphamide,
resulting in partial improvement. Six months later he was referred to the nephrology department
for rapidly progressive renal failure and a kidney biopsy was performed, which showed several
glomeruli globally sclerosed and others presenting fibrous crescents. Vascular involvement was
also noted with several small arteries revealing endothelial swelling and entrapped erythrocytes
within a fibrin thrombus. Immunofluorescence was negative. A high percentage of parenchymal
fibrosis and no evidence of active extra-renal manifestations dictated no specific treatment. The
patient is currently monitored in a low clearance nephrology consultation. Evidence of thrombotic
microangiopathy (TMA) is an uncommon histological finding in kidney biopsies of patients with
AAV, being associated with worst prognosis.
Implication for health policy/practice/research/medical education:
Evidence of thrombotic microangiopathy is an uncommon histological finding in kidney biopsies of patients with ANCA-associated
vasculitis, being associated with worst prognosis.
Please cite this paper as: Domingos AT, Barreto S, Carias E, Cabrita A, Viana E, Góis M. Renal thrombotic microangiopathy in an ANCAassociated vasculitis. J Nephropathol. 2019;8(4):e40. DOI: 10.15171/jnp.2019.40.