Part A: Clinical information
Gender, Age
Female, 50 years old
Previous illnesses
Sjögren’s disease
Time period since the onset of the first symptoms
Has had Sjögren’s disease for years, but now appears to be accompanied by a slowly progressive kidney function deterioration.
Presentation
No other symptoms related to kidney involvement – renal function deterioration detected during medical check-up.
Laboratory parameters
Proteinuria (dipstick): +
Renal function: chronically deteriorating.
Why was the decision made for a biopsy?
The combination of clinical and serological parameters are indicative for taking a kidney biopsy to confirm whether there is kidney involvement associated with Sjögren’s disease or another cause.
How long after the first symptoms was the biopsy conducted?
The biopsy was conducted at an unknown time point after kidney involvement.
Suspected diagnosis of the indication for biopsy?
TIN associated with Sjögren’s disease?
Note related to annotations: To avoid obscuring the lesions, the annotations are deliberately positioned close to, but not directly over, the lesion areas.
Part B: Kidney biopsy findings
Description of light microscopy:
Kidney biopsy consisting of 3 parts with both cortex and medulla, and around 25 glomeruli are present. Overall, glomeruli have a normal architecture. No apparent mesangial, capillary or GBM (glomerular basement membrane) lesions. The most important findings are present in the tubulointerstitium: there are multiple foci with inflammatory infiltrates, almost exclusively containing plasma cells. These can best be seen in HE or PAS staining. Plasma cells do not have atypical features. Tubular epithelium is slightly irregular. Also some casts are present with a slight hint of a so-called hard-cast appearance (however, at IF they are polyclonal). IFTA (interstitial fibrosis and tubular atrophy) is virtually absent. Vessels show no lesions.
Immunofluorescence:
No deposits of IgA, IgG, IgM, C3, C1q or kappa/lambda in glomeruli. In protein casts, light chains show a polyclonal pattern.
Considerations:
Kidney biopsy with tubulointerstitial nephritis characterized by plasma cells. No indication for a glomerular disease. Given that the patient has Sjögren’s disease, the findings could be consistent with TIN in association with morbus Sjögren. The inflammatory infiltrates are clearly visible in PAS and HE staining, but could be easily missed in the silver staining.