EPICARDIAL KERATINACEOUS CYST IN A TAWNY FROGMOUTH (PODARGUS STRIGOIDES PLUMIFERUS)

Tissues from a tawny frogmouth that died acutely in a zoo collection w ere submitted for histopathologic examination. A small yellow nodule w as observed grossly on the ventricular wall by the zoo veterinarian du ring collection of tissues. Histologically, the epicardial nodule cons isted of a well-circumscribed, thinly encapsulated cyst, 4 mm in diame ter. The cyst was composed of gradually keratinizing, attenuated, stra tified Squamous epithelium, one to three cell layers in thickness. The cyst was filled with laminated keratin and a few keratinized epitheli al cells. The cyst was separated from the myocardium by a thin layer o f adipose tissue. Based on these observations, the structure was diagn osed as an epicardial keratinaceous cyst.