CASE 163 (September 2019)
A 71-year-old woman, with a history of rheumatoid arthritis, hypertension and non-insulin-requiring diabetes mellitus, is evaluated for having edema in the lower limbs, which has recently appeared. There are no other symptoms. Creatinine 6 months ago was 1.2 mg/dL. On physical examination there is hypertension: 170/100 mg/Hg, HR: 74, with rhythmic heart sounds, neurological examination and fundus: no alterations. Edema in legs, without skin lesions.
Paraclinics: Hb: 13.5 mg/dL, hematocrit: 36%, platelets: 280,000/mm2, normal leukogram. ESR: 23 mm/h. SCr: 2.7 mg/dL, BUN; 48 mg/dL ANAs: Negative, C3: 112 mg/dL, C4; 21 mg/dL; MPO-ANCA: positive, 29 U/mL. In uroanalysis, microhematuria and leukocyturia are documented. Proteinuria: 300 mg/dL. Virus studies: negative.
See the images of the biopsy.
Figure 1. H&E, X100
Figure 2. H&E, X400.
Figure 3. PAS, X400.
Figure 4. Masson's trichrome stain, X400.
Figure 5. Masson's trichrome stain, X400.
Figure 6. Methenamine-silver stain, X400.
Figure 7. H&E, X200.
Figure 8. Methenamine-silver stain, X400.
Direct immunofluorescence: IgA, IgG, IgM, C3, C1q, kappa, and lambda: Negative.
What is your diagnosis?