Articular gout and suspected pseudogout in a Basilisk lizard (Basilicus plumifrons)

A 9-yr-old male Basilisk lizard (Basilicus plumifrons) with a history of painful and limited mobility for approximately 4 mo, which had seemed to be more pronounced in the front limbs, was presented for necropsy. The animal had exhibited moderate weight loss and anorexia before euthanasia. Postmortem examination revealed yellow-to-white, soft-to-semifirm nodules within the periarticular fascia and musculature of the left and right shoulder joints, hip joints, and stifle joints. Several other joints, including the left and right tarsi, left and right elbow joints, and the left carpus had calcified, white material present on the articular surfaces. Histopathologic evaluation of representative sections of all organs and the joints confirmed tophaceous articular gout and articular pseudogout. The differentiation between articular gout and pseudogout was based on histologic appearance, histochemical staining for calcium, and birefringence under polarized light.