The patient is a 50-year-old male who presents with a creatinine of 4.2 mg/dL (baseline 1.0 mg/dL). He has been receiving high dose methotrexate for treatment of osteosarcoma. Image 1 shows a normal glomerulus. Image 2 shows moderate interstitial fibrosis. Image 3, 4, and 5 shows polarizable silver-positive crystals within the tubular lumens. This is a case of methotrexate-induced crystal nephropathy.
Methotrexate-induced crystal nephropathy is characterized by acute tubular injury with scattered intratubular and interstitial needle-shaped, golden-brown crystals which are frequently arranged in annular structures. The crystals show birefringence under polarized light and are methenamine silver positive. Methotrexate-induced crystal nephropathy is believed to be an under-recognized entity. It has been reported in the absence of toxic methotrexate levels and the crystals can also be seen in the urine. Methotrexate-induced acute kidney injury is usually reversible and treatment is directed at volume repletion and alkalization of the urine.
https://www.ncbi.nlm.nih.gov/pubmed/26716929
https://www.ncbi.nlm.nih.gov/pubmed/30554834
Quick note: This post is to be used for informational purposes only and does not constitute medical or health advice. Each person should consult their own doctor with respect to matters referenced. Arkana Laboratories assumes no liability for actions taken in reliance upon the information contained herein.
Share this article:
Related Posts
