TABLE 1 Findings under Light Microscope and Polarizing Microscope

From: Evaluation of Crystals in Formalin-Fixed, Paraffin-Embedded Tissue Sections for the Differential Diagnosis of Pseudogout, Gout, and Tumoral Calcinosis

Group Diagnosis Patients (No.) Tissue Blocks (No.) Birefringence Under Polarizing Microscope Findings under Light Microscope
     H&E stain n (%) NAES method n (%) H&E stain NAES method
A Pseudogout 7 9 2a (22) 9 (100) positive birefringence amorphous, pale, basophilic to amphophilic material with or without foreign body giant cell reaction pale, translucent, coarse, rod- to rhomboid-shaped crystals with blunt ends
B Gout 5 8 None 8 (100) negative birefringence feathery, amphophilic material with foreign body giant cell reaction yellow-brown, needle-shaped crystals with pointed ends distributed singly or in groups simulating hay stacks
C Tumoral calcinosis 2 3 None 0 no birefringence basophilic amorphous, globular structures with surrounding giant cell reaction pale, translucent, coarse, globular calcospherites
  1. aScant occasional birefringent crystals difficult to interpret were present. These sections were not from the decalcified blocks. H&E, hematoxylin & eosin; NAES, nonaqueous alcoholic eosin staining.