Fentanyl Overdose after Cystic Ovarian Tumor Removal Surgery in a Hermaphrodite Green Anaconda (Eunectes murinus)

Abstract

Abstract A 27-yr-old female green anaconda (Eunectes murinus) presented with coelomic distention in the posterior half of its body. On examination with imaging diagnostics, a fluid-filled cavity that seemed to be related to reproductive tissue was discovered. Diagnostics of this fluid confirmed cystic fluid, and a fine-needle aspirate of the mass determined that it was ovarian tissue. Ovariectomy and mass removal surgery was performed. During surgery, there was discovery of an additional unrecognized organ near the reproductive tract. Histopathology revealed an ovarian cystic neoplasm consistent with a granulosa cell tumor, and biopsy of the unknown structure was identified as a testis. Postoperatively, the green anaconda was administered fentanyl transdermal patches for analgesia and developed a severe adverse reaction, which improved after administration of the opioid reversal agent naltrexone. This is the first report of hermaphroditism in a snake as well as suspected negative side effects of transdermal fentanyl in a snake.